View Full Version : Emerson 609 projection TV


Phil Nelson
05-02-2017, 10:34 PM
So, I'm chugging along, replacing electrolytic and paper caps in a 1949 Emerson 609 projection TV (on the left):

http://antiqueradio.org/art/DuMontRA-102CliftonWithEmerson609.jpg

In addition to the usual wax paper caps, I see about a dozen of these little guys in white cases (ceramic or porcelain?). Some have wax gooping out the ends.

http://antiqueradio.org/art/Emerson609TelevisionCeramicCap.jpg

They have values (1500pf) in the mica range, the kind of thing I'd normally leave alone during the first pass.

Are these paper caps in sheep's clothing, or something more reliable? I would rather not shotgun parts unnecessarily.

Thanks!

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

benman94
05-02-2017, 10:44 PM
Suspect caps; at the very least check a few by lifting one leg and testing it at/near rated voltage.

Plan on replacing them in any case. I'm even finding "normal" mica caps that are shot in '46 to '50 era sets.

Phil Nelson
05-03-2017, 12:31 AM
For what it's worth, they're described as "ceramic" in the Rider's parts list, although I guess that could mean garbage paper dielectric inside a ceramic tube.

All (14!) of them occur in the audio & video IF sections, where they are used for bypass, AGC filtering, and decoupling, according to Sams. Examples: C6/C8, C10/C11, and C13/C14 in this schematic snip:

http://antiqueradio.org/art/Emerson609SchematicAudio-VideoIF.jpg

I'm usually loath to replace a dozen of anything in the video IF, because . . . alignment.

Phil Nelson

Gleb
05-03-2017, 01:31 AM
I think you'd better leave them alone. Even if they're paper types, the leakage should be insignificant with such small values.

Electronic M
05-03-2017, 08:40 AM
I think you'd better leave them alone. Even if they're paper types, the leakage should be insignificant with such small values.
That may be the case with Russian made paper caps, but American made paper caps (and many Japanese caps) are crap...I've seen plenty of papers in that value range nearly dead shorted or leaking heavily even below 50V.

bandersen
05-03-2017, 08:58 AM
I can see "HI-Q" printed on the side. All the vintage caps I've encountered that look like that have been true ceramic and just fine. I'd leave them alone.

Kevin Kuehn
05-03-2017, 11:34 AM
At that point in time I don't believe the state of the art even allowed winding paper caps that small? Well maybe, but they'd of been too expensive for consumer electronics.

Phil Nelson
05-03-2017, 12:08 PM
Thanks, I'll leave 'em in peace for now.

These caps are definitely smaller than any of the TV's paper caps in that general range (.001, .003).

Phil Nelson

Eric H
05-03-2017, 01:34 PM
I've found those in other sets and left them alone, they don't seem to be troublesome.

I suppose you could replace one and bust it open to see what it is inside.

Phil Nelson
05-03-2017, 07:22 PM
Here's the ceramic cap next to the smallest paper cap in this TV:

http://antiqueradio.org/art/Emerson609TelevisionCeramicCap01.jpg

My Dumont RA-102 has a number of ceramic caps about the same size as these, but they have a different profile, more like a dogbone style resistor, and no wax dripping out the ends.

Phil Nelson

M3-SRT8
05-06-2017, 08:26 PM
I see those all the time, and I've always left them alone.

In 30 plus vintage TV restorations I might have replaced one, and I didn't have to.:smoke:

Phil Nelson
05-09-2017, 07:24 PM
After replacing the factory-installed electrolytic and paper caps on my Emerson 609, I'm looking at this big .25-mfd paper cap, evidently added by some sloppy repairman:

http://antiqueradio.org/art/Emerson609TelevisionWidthCoilAddedCap01.jpg

The cap isn't shown in either Riders or Sams. It's hard to trace things in this messy chassis full of long, wandering leads. But as near as I can make out, the guy wired this new cap in parallel with the Horizontal Size adjuster coil (L-8 in Riders):

http://antiqueradio.org/art/Emerson609TelevisionWidthCoilAddedCap02.jpg

Any ideas as to why someone would add this? Tacking stuff onto a width coil suggests an attempt to get more (or less?) width, at first glance . . . .

I normally remove mods and restore things to match the schematic, especially messy work like this, on the theory that the repairman was attempting a quick fix for some symptom that will be cured by the time I'm done recapping, etc. But if someone thinks this is a great improvement, I suppose I could try a new .25 cap there.

You can read the full schematic here:

http://antiqueradio.org/art/Emerson609TVSchematicSmall.jpg

Regards,

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

M3-SRT8
05-09-2017, 08:43 PM
That is a width mod. I've seen .05 uF caps occasionally attached to RCA KCS-20 flybacks to fix a width issue.:smoke:

Phil Nelson
05-10-2017, 05:02 PM
OK, that rogue cap is gone.

In preparation for powering up, I checked out the five-element ballast (Emerson # 397023). Most of the elements test bad. There's a lot of corrosion where the elements join the pin leads. Even if I could coax it back into life, this doesn't seem like a good bet for long-term reliability:

http://antiqueradio.org/art/Emerson609Television397023Ballast.jpg

http://antiqueradio.org/art/Emerson609Television397023BallastDiagram.jpg

I found an eBay supplier with a Clarostat ballast, so let's hope that one works. Can't wait!

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

Phil Nelson
05-20-2017, 01:05 AM
It's alive!

https://antiqueradio.org/art/Emerson609TelevisionFirstImage.jpg

OK, that looks underwhelming, but it's exciting to me. After replacing the ballast and doing, well, a bunch of other stuff, tonight I saw the first coherent image on the Emerson's little 3NP4 CRT. (That's the Xfinity cable TV guide screen, in case you're wondering).

With the chassis spread all over the workbench, there's nothing to project on (the ceiling's much too far away to focus). So peering slantwise down into the Protelgram optic box is the only way to see what's happening.

This set had more problems than I had noticed at first, including an under-chassis meltdown that burned everything around the sockets of the vertical and 1st video IF tubes. But now, the vertical & horizontal are stable, brightness & contrast work as advertised, and the audio is excellent.

There's more checking and tweaking to do, but it's always fun to see the first signs of life.

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

M3-SRT8
05-20-2017, 12:42 PM
Ahhh! Isn't it fun? Even though we've restored countless old tvs, it still puts a smile on your face when another one springs back from the dead.

Well done. Keep us posted. :smoke:

Phil Nelson
06-02-2017, 06:53 PM
After recapping & whatnot, the electronics are working pretty well on my Emerson 609. The optical (Norelco Protelgram) portion . . . not so wonderful.

https://antiqueradio.org/art/Emerson609TelevisionFirstPicture.jpg

Apart from issues like bad horizontal linearity, which is only an adjustment, the image is not only dim, but unable to focus despite fiddling with the electronic and mechanical focus adjusters.

The 45-degree mirror in the optics box appears to be in bad shape:

https://antiqueradio.org/art/Emerson609TelevisionBadMirror.jpg

Is this the mirror that people send out to be resilvered? If so, where?

I haven't made any attempt to clean it, having read horror stories in the past about people who destroyed projection TV components by inappropriate cleaning.

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

Eric H
06-02-2017, 07:45 PM
How does the image look directly on the CRT? (I use a mirror to avoid X rays)
I've cleaned these mirrors with soap and water, I even removed the silvering on one and it was really tough to do, that said it will depend on what condition it's in to begin with.

Phil Nelson
06-02-2017, 08:50 PM
The image on the CRT looks good, although it's a little hard to judge when peering in at such an angle. Of course, the smaller the CRT, the sharper things look, too. If I remove the side plates from the optics box, I should be able to inspect the mirrors more closely.

On another note, has anyone ever seen patent documents for the Norelco Protelgram unit? I assume it was patented somewhere, although a quick search of US patents didn't turn up anything.

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

madlabs
06-03-2017, 03:43 PM
Never cleaned a TV mirror but I have cleaned telescope mirrors, which I imagine are affected more by scratches. I use water and soap, a squirt bottle with warm soapy water blasted right on a chunk of smeg will usually get it off. Soak and blast. soak and blast. Garden hose type of pressure washer is good too. Just don't use anything in actual contact with the mirror. That seems to work well with dust/disuse build up.

I have also under duress used a super soft artists paint brush on a mirror that was really gunked. As it turned out the mirror was trashed but I didn't see any scratches from working it GENTLY with the brush.

You can get the mirror redone. If you look for places that make telescope mirrors you can sometimes have them do yours when they are doing another and save some dough. Can take a while that way. I had a mirror I home ground done that way, took two months but was cheap.

pearsonk
06-03-2017, 04:10 PM
Make sure the cardboard/fiber shield is on the crt. From the pics, it looks
like the crt is not as far in as it should be [if memory serves me]. I always
use distilled water on these mirrors to avoid water marks after drying.
I have restored several of these Norelco units and have NOS 3np4s and a resilvered concave mirror........
Currently have a Scott and an Emerson with the Norelco system.

Samuel1981
06-17-2017, 09:03 PM
Update?

batterymaker
06-17-2017, 10:08 PM
Anyone see this? Perhaps a cheaper way to get your mirror re-done

https://www.youtube.com/watch?v=z8iTQwnDaLg

Eric H
06-17-2017, 10:51 PM
Anyone see this? Perhaps a cheaper way to get your mirror re-done

https://www.youtube.com/watch?v=z8iTQwnDaLg

The problem with that is the mirrors in a projection set are on the surface of the Glass, that is behind it.

Tom Albrecht
06-17-2017, 11:16 PM
I had a mirror resilvered (or more precisely, re-aluminumed) for my Philco projection TV. This outfit does a good job, and won't break the bank. You'll see they show prices right on their website: http://www.spectrum-coatings.com/

The symptom of a bad mirror is poor contrast. Too much light scatters off the rough and dirty spots on the mirrors, putting some light into the dark areas of your picture that doesn't belong there. It will not cause bad focus, so that is a separate problem to be worked out.

Here's a thread on ARF from when I got my mirror recoated: http://www.antiqueradios.com/forums/viewtopic.php?f=3&t=67808&p=524069#p524069

Later I made some further improvements to the set, that resulted in better pictures than I showed in the thread linked above.

Phil Nelson
06-23-2017, 03:16 PM
Thanks for the info. We have been away on vacation, but I will probably get a chance to open up the optical box this weekend. I suspect I'll send off the mirror for resilvering.

Apart from that, the TV still needs more work on the focus and horizontal sweep sections.

Regards,

Phil Nelson

Samuel1981
06-24-2017, 07:55 PM
Keep chugging along! This is one of the prettiest of the projection sets.

Phil Nelson
06-26-2017, 08:05 PM
Well, I got the 45-degree mirror out. Kind of a tricky process. First, you remove the side panels from the box:

https://antiqueradio.org/art/Emerson609TelevisionMirrorRemoval00.jpg

After removing four nuts, you can draw out the entire tailpiece assembly (including CRT) from the rear:

https://antiqueradio.org/art/Emerson609TelevisionMirrorRemoval01.jpg

Use care when sliding out this heavy assembly. Judging by some little nicks around the hole edges in the 45-degree mirror, this CRT was replaced in the past.

The spherical mirror must come out first, to make enough elbow room to withdraw the 45-degree mirror:

https://antiqueradio.org/art/Emerson609TelevisionMirrorRemoval04.jpg

You must unscrew the 45-degree mirror clamps from the slanted rails, and then remove the clamps from the mirror. Then with some cautious jiggling and sliding, you can slip the mirror out the side of the box:

https://antiqueradio.org/art/Emerson609TelevisionMirrorRemoval05.jpg

The reflective surface looks pretty bad, so off it goes for resilvering:

https://antiqueradio.org/art/Emerson609TelevisionMirrorRemoval06.jpg

The spherical mirror looks much. much better, so I may try to use it as-is.

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

Phil Nelson
06-30-2017, 02:51 PM
Is there a way to test my 3NP4 CRT? My Sencore CR70 manual doesn't list settings for it.

The CRT is obviously good enough to make some sort of picture, but it's hard to judge its performance by looking at that tiny CRT face, and I can't view the full image at all, while the mirror is off for recoating.

The turnaround time for recoating is something like 30 days, so I'll try to make progress in other areas in the meantime. I hope to be able to address the horizontal issues by viewing scope forms and peeking in at the CRT face.

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

Phil Nelson
07-27-2017, 09:43 PM
The recoated mirror is back from Spectrum Coatings (https://www.spectrum-coatings.com/), and it looks good.

https://antiqueradio.org/art/Emerson609TelevisionPlaneMirrorRecoated.jpg

We're about to leave on a short vacation, but next week I should be able to install it and give the 609 another trial.

Fingers crossed,

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

Tom Albrecht
07-28-2017, 10:54 PM
That looks a lot better!

Phil Nelson
08-08-2017, 06:17 PM
Sigh. I was full of hope when I reinstalled the recoated mirror, and then things began to go south. At first, the only problem was (still) bad focus, and when I changed one resistor in hopes of addressing that issue, the image size suddenly shrank by about half.

You can read more (much more) by looking at this article-in-progress; it includes links to the full Riders and Sams service manuals, as well as a pretty full recap (get it?) of what work I've done so far:

https://antiqueradio.org/Emerson609ProjectionTelevision.htm

Scroll down to the end if you're impatient and want to know where things stand at the moment.

Has anyone restored an Emerson 609 before? I'm fairly confident about the electronic side, but the Norelco Protelgram optical box with its mirrors & lens & whatnot is new to me.

I'd appreciate any advice from someone who has tamed one of these beasts. At this point, my plan is to move all the chassis back onto my workbench and start looking for a cause of the sudden reduction in image size. You can see on the CRT face that the image is smaller than normal, so I assume the problem is on the electronic side, not in the optical/mechanical parts.

Thanks!

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html[/url]

vts1134
08-08-2017, 06:35 PM
Hang in there Phil, this is the toughest phase of a restoration...pulling the chassis back out :sigh:. We've all been there and it's no fun. Keep at it and you'll tame the beast!

Eric H
08-08-2017, 07:21 PM
At least the CRT looked like it was bright when it was working.

I have an RCA Projection set that I've kind of lost interest in, it's such a nightmare dealing with all the chassis's (Chassi?) in the darn thing, plus having to trying to carry the barrel along with the sweep chassis since they can't be easily separated.

Crist Rigott
08-08-2017, 08:47 PM
Hang in there Phil. Your articles have helped a lot of people. I'm confident that you'll get it fixed and it will be working great.

old_coot88
08-08-2017, 09:19 PM
Since both H and V sweep are reduced equally, seems like the fault would have to be B+ related and pretty easy to nail.

Phil Nelson
08-09-2017, 12:14 AM
Check B+ . . . We hear and obey (tomorrow).

Thanks,

Phil Nelson

Phil Nelson
08-09-2017, 02:13 PM
Ding-ding-ding! old_coot88 was on the mark, as usual. Broken lead between C6 and junction of M3/M4 in the Sams schematic, so no juice coming down that line.

Simple to diagnose (once you know where to look), and a big fat pain to fix. It will take 1/2 hour of horsing around to get all the heavy chassis out of the cabinet and back into the workbench, and about 1/2 minute to repair the break!

While it's on the bench, I'll be able to view the CRT face and judge the focus there.

Later,

Phil Nelson

Electronic M
08-09-2017, 03:31 PM
If face focus is good, look into optical focus. There may be mechanical adjustments for it.

Phil Nelson
08-09-2017, 05:00 PM
Yes, there are several mechanical adjustments, as the Rider manual shows in detail.

I temporarily reconnected the broken wire with a clip lead, which brought back the power supply and full deflection. Now I'm back where I was before, with lousy focus. This is the best I can get using the two electronic focus controls:

https://antiqueradio.org/art/Emerson609TelevisionDeflectionRestored.jpg

The focus on the CRT face looks good to my eye, so I'm guessing that one or both of the reinstalled mirrors is cockeyed. I didn't mess with any of the mechanical adjusters before, such as the tilt adjusters on the base of the box. It's possible that some adjuster was seriously screwed up long ago, but the image that I got before resilvering the mirror was much closer to focus (and correct screen geometry) than this. Maybe I'll spot something obvious after I open the optical box back up.

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

old_coot88
08-09-2017, 06:07 PM
This is a dumb question, but does the resilvered mirror have a protective film that needs to be peeled off?

The reason for asking is, I got skunked that way once with a new camera that was blurry til I figgered out what was causing it.:o

jr_tech
08-09-2017, 07:12 PM
Is the mirror adjusted to be exactly 45 degrees to the optical axis?

jr

Zenith6S321
08-09-2017, 07:48 PM
If face focus is good, look into optical focus. There may be mechanical adjustments for it.

I agree, that with good focus on the CRT, the poor focus on the screen must be due to a miss-alignment in the optical path.

I have not worked on your projection TV model, but I have adjusted Barco projectors that have a Scheimpflug lens mount that allows you to adjust left-right and top-bottom optical focus. If you can tilt either the CRT face, the projection screen, or possibly the lens plane you may be able to correct the problem. See if you can find any mechanical adjustments that will let you tilt one optical element with respect to the others. I suggest you try to get good focus at the center of the image and then tilt the CRT, lens, or projection screen to adjust left-right and then top-bottom focus.

Dave

Phil Nelson
08-10-2017, 01:16 AM
There wasn't any protective film on the resilvered mirror.

I didn't measure the angle of the plane mirror, so that's worth checking. There is very little range of movement for that mirror, once you have adjusted it so that the CRT is centered and clears the hole. There's a bit of elbow room, however. There are no adjusters for the spherical mirror, which is bolted perpendicularly inside the front wall of the box.

The manuals say nothing about installing or adjusting these mirrors, which was outside the scope of ordinary service, I guess. They must have used special jigs in the factory for this task. Due to X-rays, you can't loosen the mirrors and fiddle with them to watch the effect while the TV is playing, so the process might be tedious:

-- Make a little adjustment.
-- Close up box.
-- Turn on TV and view the screen.
-- Turn off TV and open the box.
-- Repeat as needed.

The manual does describe a bunch of adjusters for the optical system, including one on the corrector lens, but I don't want to mess with those until I confirm that the internal mirrors are installed as well as I can manage.

Phil Nelson

old_tv_nut
08-10-2017, 10:35 AM
I think the optics should work in the reverse direction, so it would be possible to put a printed test pattern in place of the screen, illuminate it brightly, and observe the image on the tube. But probably not worth going there if there is little adjustment available.

I think I would continue to verify the internal mirrors are installed correctly and then move on to the described adjusters, as you say.

jr_tech
08-10-2017, 10:53 AM
Or, perhaps shine a laser pointer on the center of the screen and see if it is visible in the center of the 3np4. :scratch2:

jr

Phil Nelson
08-10-2017, 07:50 PM
I pulled the chassis and opened the optical box. I thought that the spherical mirror could only be mounted in one way, bolting onto the rear wall of the box. While it doesn't have adjusters as such, now I see that the holes in the box are bigger than its mounting screws, providing some wiggle room:

https://antiqueradio.org/art/Emerson609TelevisionSphericalMirrorScrew.jpg

Large washers go on both sides of the hole, so clearly some sliding back & forth was contemplated.

With all three screws loosened, you can slide the mirror a bit in any direction. Not foreseeing that alignment would be an issue, I have no record of exactly how it was mounted before I removed the mirrors. Nor do I know exactly where it was mounted when it produced the most recent picture, since I didn't know the screws had any leeway until I had loosened them all today.

I don't have a factory jig for aligning all this stuff, so unless someone has a better idea, I'll mark the box with tape tags showing the center of each mounting hole, and try to remount the mirror dead center in all three holes.

Also on my to-do list is checking the angle of the plane mirror to make sure it's exactly 45 degrees, and to ensure that each of the three side clamps is holding it the same distance from the struts (i.e., even if it's lying back exactly 45 degrees, it's not tilting sideways, either).

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

jr_tech
08-11-2017, 10:41 AM
You need one of these!

http://www.earlytelevision.org/philips_test.html

Perhaps something similar could be fabricated. :scratch2:

jr

Phil Nelson
08-11-2017, 11:52 PM
Wow, that Philips gizmo is clever. It sure would simplify the optical adjustment process, although fabricating one goes far beyond my pay grade.

Meanwhile, I reopened the optical box today. After much fussing & cussing, I readjusted the spherical and 45-degree plane mirrors. Now, the picture is similar to what it was before I pulled those mirrors for resilvering:

https://antiqueradio.org/art/Emerson609TelevisionMirrorsAdjusted.gif

I haven't yet done ANY of the multiple mechanical adjustments, so the picture is blurry and the screen geometry isn't perfect. Presumably things can be improved somewhat that way.

It also looks a little bloomy on high-contrast content, as you can see in the animated .GIF. Poor HV regulation? There's no quick/easy way to measure the HV output, as you would in a conventional TV, so this is only a guess.

Speaking of mirrors, I stuck my head up inside the pop-up canopy to inspect the big (final) mirror. Guess what -- it looks bad, similar to the degraded surface on the 45-degree plane mirror. That would explain some of the image weirdness seen in the last photo, which is more than just being out of focus.

Tomorrow . . . .

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

jr_tech
08-12-2017, 12:53 AM
I may be wrong, but I think that the vertical keystone can be improved by a side to side adjustment of the 45 degree mirror. I would not assume that the 45 degree rails are perfect. :scratch2:

The focus looks fairly uniform, I suspect that moving the CRT foreward or backward will sharpen it quite a bit... perhaps put a dab of lubricant on each of the 3 "fingers" that move the CRT mount so the focus action is smooth.

jr

Phil Nelson
08-12-2017, 10:58 PM
Yah, I'm probably not done messing with that plane mirror.

Looking up top, I noticed that the screen's wooden frame is slightly cracked open on one side; thus, that corner of the frame doesn't slide forward all the way when you lock the screen in viewing position. Which means the big mirror is also misaligned.

Note the gap on the right side, between the screen frame and the control panel frame:

https://antiqueradio.org/art/Emerson609TelevisionScreenFrameMisaligned.jpg

I guess these things happen when a fragile, heavy cabinet is trundled around from house to house over the decades :-(

I was planning to remove the canopy anyway, to give the big mirror a close inspection. Now I have two reasons to remove it!

Regards,

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

jr_tech
08-13-2017, 04:06 PM
Wow, that Philips gizmo is clever. It sure would simplify the optical adjustment process, although fabricating one goes far beyond my pay grade.


Perhaps not... jr crazy idea for the day:

Apply some sort of pattern to the face of the tube, transfer letters, decal, felt tip pen, whatever you have handy.

https://farm5.staticflickr.com/4434/36549879575_4e63acd737_z_d.jpg

Install tube in the box and illuminate face with bright flashlight. Fenix MC-10 shown here.

https://farm5.staticflickr.com/4435/36503425976_6485f2cdaf_z_d.jpg

View on screen approximately 31 inches from the corrector plate... Align for best image.

https://farm5.staticflickr.com/4391/36549887605_9e59371f50_z_d.jpg

Of course, the set up could be much better, but this was just a quick n dirty experiment to illustrate the concept, using a washing machine instead of a flat level table as an "optical bench" and a clipboard with white piece of paper instead of a proper screen.

jr

old_coot88
08-13-2017, 07:29 PM
Phil you are da man when it comes to MacGyvering. :D

Phil Nelson
08-13-2017, 09:52 PM
Yeah, something like that flashlight setup might work for aligning the optical box mirrors.

Meanwhile, I managed to extract the canopy with its final mirror & screen. (Hint: this process is a pain; don't do it without a good reason.)

https://antiqueradio.org/art/Emerson609TelevisionCanopy01.jpg

The final mirror doesn't look that bad from a distance:

https://antiqueradio.org/art/Emerson609TelevisionCanopy02.jpg

The closer you get, the worse it looks, showing the same flaws as the 45-degree mirror in the optical box. This isn't dirt; I cleaned the mirror, with no change in the degraded areas:

https://antiqueradio.org/art/Emerson609TelevisionCanopy03.jpg

Yes, this frame corner has popped loose (and so has the adjacent one). This rail would fall out completely if the screen mount wasn't holding it from behind:

https://antiqueradio.org/art/Emerson609TelevisionCanopy04.jpg

I'll pull the mirror from the canopy and send it off for recoating. That will take about a month, and during that time I can do cabinet refinishing & repair (it also has a broken leg). Maybe some MacGyver experiments, too!

Phil Nelson
Phil's Old Radios
https://antiqueradio.org/index.html

Crist Rigott
08-13-2017, 10:27 PM
Hang in there. If anybody can get this thing right you'll be the one.

Phil Nelson
08-13-2017, 11:44 PM
Thanks for the encouragement. I bought this set thinking that a projection TV might be an interesting new challenge. I got that wish, and then some!

Phil Nelson

Phil Nelson
04-24-2018, 12:45 AM
I have been puttering along with this set in recent months. After recoating two mirrors and spending more time with the electronics, it makes a better semblance of a picture:

https://antiqueradio.org/art/Emerson609TelevisionFirstPicAfterReassembly.jpg

As you probably noticed by Sam's stretched head in that pic, the horizontal linearity is pretty awful. This test pattern shows that the vertical linearity is also poor:

https://antiqueradio.org/art/Emerson609TelevisionFirstTPAfterReassembly.jpg

I have gone back through the sweep circuits, replacing a handful of components, without finding an obvious cause for bad linearity in both directions.

If you go back to page 1 of this thread, you'll see that I removed a one-capacitor modification made by a previous owner: that cap paralleled the width coil and the idea seems to have been to affect the width.

Now I'm tempted to reinstall a cap in that position and see what happens . . . .

If I can't solve the linearity problem with the electronics, I'm back to fiddling with the optics, which I honestly don't understand very well. One idea that occurred to me is that maybe I reinstalled the recoated spherical mirror off-kilter. Testing that theory would be difficult, since that mirror's mounting screws are not intended as adjusters. There's a lot of elbow room for the screws in those holes and absolutely no guide as to what is the correct position. In the factory, I supose they set this mirror using a jig.

I've been updating my restoration article as I go along. You can read more details and see more pics at: https://antiqueradio.org/Emerson609ProjectionTelevision.htm .

Regards,

Phil Nelson
Phil's Old Radios
https://antiqueradio.org/index.html

kvflyer
04-24-2018, 07:36 AM
How does the image look directly on the CRT? (I use a mirror to avoid X rays)
I've cleaned these mirrors with soap and water, I even removed the silvering on one and it was really tough to do, that said it will depend on what condition it's in to begin with.

Tom, I skimmed this thread and apologize if I missed the answer. But... is it possible to look directly at the CRT and determine if the picture is in good linearity? I realise that may be a pain to remove or whatever. I just wonder if viewing that picture directly may save a lot of headaches in the process.

Sorry if I am asking the obvious. I really want this to be another success for you!

old_tv_nut
04-24-2018, 10:48 AM
Hard to believe the optics could do all that. Maybe some combo of scan and optics, but I really think scan is most likely the cause of it all.

With all that distortion at 6 o'clock and 9 o'clock, you'd think the range of 7-8 o'clock would be worse yet if it were optics.

Phil Nelson
04-24-2018, 12:23 PM
is it possible to look directly at the CRT and determine if the picture is in good linearity?When the CRT is in the optical box, you can only view the CRT face from the side:

https://antiqueradio.org/art/Emerson609TelevisionFirstImage.jpg

But if you remove the entire tailpiece assembly, you could view the CRT face fully:

https://antiqueradio.org/art/Emerson609TelevisionMirrorRemoval01.jpg

I'm concerned about X-rays in that scenario. At 25KV, X-rays are a factor, so would you get fried if you view the CRT outside the metal box?

Somewhere, I saw a statement from bandersen that more X-rays are generated from HV rectifier tubes than the CRT itself. Can anyone verify that? In this set, the HV rectifiers are sealed in their own little metal box, so if the CRT itself isn't a big emitter, maybe viewing it outside its box wouldn't be so dangerous . . . ?

Phil Nelson
Phil's Old Radios
https://antiqueradio.org/index.html

Electronic M
04-24-2018, 12:50 PM
I t should be fine.... If you're still worried and have one of those TV magnifier accessories for 10/12" sets place it in front of the CRT and stand back a few feet...X Ray's are exponentially attenuated by air. Even if the CRT were a strong emitter once you get about 4 ft away the dose should be well within safe limits.

Another worry wart option would be to grab the leadded safety glass off of a color set and place it between the CRT and you.

old_coot88
04-24-2018, 01:09 PM
If there wuz anything to the Xray scare, all my kids should have two heads and six fingers.

:):D

old_tv_nut
04-24-2018, 05:28 PM
25kv is starting to produce X-rays, and unlike color CRTs, that one most likely does not contain enough lead or thickness to reduce them. As said above, standing back several feet should be good enough protection. Also, X-ray effects are cumulative, so if you just have a quick look to see the shape of the circle, no problem. As an additional measure, you can turn down the brightness and run at much lower beam current for direct viewing.

WISCOJIM
04-24-2018, 05:47 PM
What about trying to view the CRT image in the reflection of a regular mirror. Can you get one in position to do that?

.

old_tv_nut
04-24-2018, 06:13 PM
What about trying to view the CRT image in the reflection of a regular mirror. Can you get one in position to do that?

.

X rays do not beam straight out the front. They spread in all directions.

WISCOJIM
04-24-2018, 09:22 PM
X rays do not beam straight out the front. They spread in all directions.
I was thinking of giving him an angle to see inside, such as using a hand mirror.

.

EdKozk2
04-24-2018, 10:35 PM
Hi Phil,
Your picture of the egg shaped vertical test pattern reminded me of the issue I had with my Stewart Warner 9100 mirror lid set. In order to correct it in my case I made a change to the RC time constant in the plate circuit of the vertical blocking oscillator. The original per Sams' was a 0.15mfd cap and a 2200 ohm resistor. I ended up using a 0.1mfd and 330 ohm resistor to get a balanced ellipse vertically. Increasing the width adjustment then made the the image circular.
You made great progress.:thmbsp:
Ed

Phil Nelson
04-26-2018, 07:22 PM
If you go back to page 1 of this thread, you'll see that I removed a one-capacitor modification made by a previous owner: that cap paralleled the width coil and the idea seems to have been to affect the width. Now I'm tempted to reinstall a cap in that position and see what happens . . . .

Well, putting a cap (something from .33 to .66) across the width coil increases the width and lets you adjust for somewhat better horizontal linearity.

For comparison, here's the previous test pattern:

https://antiqueradio.org/art/Emerson609TelevisionFirstTPAfterReassembly.jpg

And here's today's pattern:

https://antiqueradio.org/art/Emerson609TelevisionTPAfterWidthCoilMod.jpg

Not a great improvement, but something. It still feels like the horizontal circuits are just "off" in general -- the adjusters for horiz drive, horiz linearity, and horiz size are all maxed in one direction.

The worst horizontal linearity is not at the far left edge, but in a band that starts maybe 20% in from the left edge. If you squeezed that band horizontally, you'd have a pretty watchable picture.

Strangely, now it's easier to adjust for better vertical linearity.

Phil Nelson
Phil's Old Radios
https://antiqueradio.org/index.html

kvflyer
04-27-2018, 04:03 PM
Have you ruled out optics and are now focused (pun intended) on the sweep circuits? I know that you were reluctant to view the face of the actual CRT.

Username1
04-27-2018, 08:42 PM
Kindof a slow evening, and this thread caught my attention....

" Not a great improvement, but something. It still feels like the horizontal circuits are
just "off" in general -- the adjusters for horiz drive, horiz linearity, and horiz size are
all maxed in one direction. "

I wonder, Could you post a picture however bad it may look with all those knobs
set at mid-point...?

Another goofy thought..... Is there any chance that the metal housing with all
that optics has been magnetized...?

I guess a quick answer might come if you looked at the picture outside all
that optics..... But then I did read about your worry of x-rays....

With both H and V off in linearity, are the V lin and V height also maxed in one
direction ?

Seems like a voltage rail common to both H and V would be a good place to look.

Looks like that will be a neat tv !


.

Phil Nelson
04-27-2018, 10:03 PM
I decided not to mess with the optics until I have more faith in the electronics. Looking back at my notes, I saw several components still unchecked in the vertical & sync circuits. Plus, I want to check voltages in the sync & sweep circuits. The Sams manual doesn't show any oscilloscope waveforms, but the Riders manual includes a few, so scoping is also on the list.

Time to finish my homework, in other words, before I look for more exotic causes.

The first resistor I checked today was a 3W dogbone style. It's spec'd at 10K and it measured at 24K (!). At first glance, you might think it's wirewound, but this just looks like a fat carbon rod with leads attached to the ends. Way out of spec, anyhow.

I believe the vertical linearity control was also maxed. Not vertical size, though.

Hope to spend more time on this over the weekend.

Phil Nelson
Phil's Old Radios
https://antiqueradio.org/index.html

Josef
05-02-2018, 07:43 PM
I'd reverse the vertical and horizontal deflection wires and see what happens. If the pattern is mirrowed the defect comes from the electronics, if it stays the same the optics are faulty :scratch2:

Tom9589
05-02-2018, 09:15 PM
I don't think that will work as the horizontal and vertical yoke windings are quite different in resistance and inductance.

Phil Nelson
05-02-2018, 09:42 PM
I thought Josef meant swapping the horizontal wires (pins 5 & 7 in the schematic) with each other and then swapping the vertical wires (pins 2 & 6) with each other. (In other words, not swapping the pair of horizontal wires with the pair of vertical wires.) Or am I misreading one or both of you?

Phil Nelson

https://antiqueradio.org/art/Emerson609TelevisionScanSchematic.jpg

EdKozk2
05-02-2018, 10:23 PM
Hi Phil,
Just reversing the two horizontal wire connections within the same circuit is what makes sense. The same would go for the vertical connections. One thing to watch for is if the picture is reversed. Lettering or words on the final viewed image will be incorrect. Just like putting a slide in a slide projector backwards.
Ed

Josef
05-03-2018, 02:09 AM
Hi Phil,
Just reversing the two horizontal wire connections within the same circuit is what makes sense. The same would go for the vertical connections. One thing to watch for is if the picture is reversed. Lettering or words on the final viewed image will be incorrect. Just like putting a slide in a slide projector backwards.
Ed

That's exactly what I wanted to point out. Sorry for causing misunderstandings- I'm not native speaker.

Phil Nelson
05-03-2018, 05:12 PM
No problem! It's a clever idea. I may get a chance to try it in a day or two.

Regards,

Phil Nelson
Phil's Old Radios
https://antiqueradio.org/index.html

Phil Nelson
05-04-2018, 07:10 PM
I'd reverse the vertical and horizontal deflection wires and see what happens. If the pattern is mirrowed the defect comes from the electronics, if it stays the same the optics are faulty :scratch2:Josef's test shows that the defect is in the electronics.

I reversed only the horizontal wires (pins 5 and 7 in the previous schematic). That should answer the basic question. Here, they are connected normally:

https://antiqueradio.org/art/Emerson609TelevisionReversingHorYokeWires.jpg

Horizontal wires connected normally:

https://antiqueradio.org/art/Emerson609TelevisionHorYokeNormal.jpg

Horizontal wires reversed:

https://antiqueradio.org/art/Emerson609TelevisionHorYokeReversed.jpg

The distortion flips horizontally, so clearly the big defect lies in the electronics. Thanks for suggesting this simple test, Josef!

That's actually a relief. Although I don't have an immediate solution for the electronics, that sort of problem-solving should be easier than trying to fiddle optical parts inside the Protelgram "black box" without the factory jigs originally used to align them.

Now I will put the three chassis back onto the workbench and resume my homework (testing voltages, etc.).

Regards,

Phil Nelson
Phil's Old Radios
https://antiqueradio.org/index.html

Phil Nelson
05-30-2018, 04:26 PM
I finished my voltage-testing homework, checking all the voltages against the chart in the Sams manual (https://antiqueradio.org/art/Sams%2090-6.pdf). This spreadsheet shows the test results (ideal = voltage from the manual, actual = measured voltage):

https://antiqueradio.org/art/Emerson609TelevisionVoltages.xlsx

The tests were done with the line voltage held at 117VAC on a variac. I turned down the brightness and audio volume controls; the horizontal & vertical hold controls were set for a normal picture.

Not surprisingly, given that most of the TV works fine, most of the voltages are in about the right ballpark. The filament voltages look somewhat low everywhere, measuring about 5.7 - 5.8VAC rather than 6.3 volts. None of the other results looks like a big red flag, although possibly I'm misinterpreting something.

I'm back to seeking a cause for the bad horizontal linearity. As mentioned earlier, adding a cap across the width coil increased the width and somewhat affected the linearity, but it wasn't a miracle cure. I suppose I could go back and fiddle with different values for that cap.

There isn't much else to tweak in that circuit, although I see two caps on either side of the horizontal linearity adjuster (C-65 and C-64 in the Riders schematic below). Those wouldn't be difficult to change, if there's a reason to try that.

Any other ideas?

Phil Nelson
Phil's Old Radios
https://antiqueradio.org/index.html

https://antiqueradio.org/art/Emerson609TelevisionScanSchematic.jpg

old_tv_nut
05-30-2018, 05:13 PM
What type of caps and values are C-64 and C-65? If you have no way to test, substitution is surely a good idea - after all, that coil they're attached to does say H lin.

Phil Nelson
05-30-2018, 09:25 PM
The originals were 600-volt rated paper caps, which I replaced during the first recapping pass. C64 is .035 and C65 is .05, which look like pretty standard values for those caps in my old TV books.

I replaced them with modern film caps (the brown chiclet style) rated for 630V. I paralleled two caps to make up the .035 cap.

I guess it's possible that one of the replacement caps is bad or that I (shudder!) installed a wrong value. I can disconnect and test them.

Phil Nelson
Phil's Old Radios
https://antiqueradio.org/index.html

old_tv_nut
05-30-2018, 09:42 PM
I have less confidence that they are the problem, since you replaced them, but it doesn't hurt to double check. There seem to be two things going on: left and right not the same width (usual sort of linearity problem), and sides much wider than the center. I don't understand the circuit well enough to point to a possible cause or causes.

Did you replace C-76 and C-77?

Phil Nelson
05-30-2018, 10:28 PM
C76/C77 are 1000-mfd/15V electrolytics, which I replaced with new 25V-rated electrolytics. All paper & electrolytic caps have been replaced.

Phil Nelson

Electronic M
05-30-2018, 11:08 PM
The originals were 600-volt rated paper caps, which I replaced during the first recapping pass. C64 is .035 and C65 is .05, which look like pretty standard values for those caps in my old TV books.

I replaced them with modern film caps (the brown chiclet style) rated for 630V. I paralleled two caps to make up the .035 cap.

I guess it's possible that one of the replacement caps is bad or that I (shudder!) installed a wrong value. I can disconnect and test them.

Phil Nelson
Phil's Old Radios
https://antiqueradio.org/index.html

On other sets of the day that were based on the RCA 630 those caps on the linearity coil were 1000V IIRC. Are you sure the 600v ones you found in it were original?

Phil Nelson
05-30-2018, 11:44 PM
They are specified as 600V in both the Sams and Riders parts lists, for what thatís worth.

Phil Nelson

old_tv_nut
05-31-2018, 12:28 AM
C76/C77 are 1000-mfd/15V electrolytics, which I replaced with new 25V-rated electrolytics. All paper & electrolytic caps have been replaced.

Phil Nelson

OK, they are just huge filters to bypass all AC. I was guessing that, but wasn't sure if they could be smaller values that could shape the waveform. Never mind.

Phil Nelson
06-20-2018, 12:33 AM
There isn't much else to tweak in that circuitIn the damper circuit, there is a 25-watt wirewound filter resistor (R86), which turned out to be open!

https://antiqueradio.org/art/Emerson609TelevisionDamperSchematic.jpg

It's one of those guys that stands upright inside the high voltage cage.

https://antiqueradio.org/art/Emerson609TelevisionDamperFilterResistorBad.jpg

https://antiqueradio.org/art/Emerson609TelevisionDamperResistorNew.jpg

Replacing it cured the worst horizontal geometry problems, but then the width was insufficient. Earlier in the project, I had removed a .25 paper cap that someone tacked in parallel with the width coil (L8).

https://antiqueradio.org/art/Emerson609TelevisionWidthCoilAddedCap02.jpg

I experimented with a decade box and found that .25 was indeed about the right value to bring the width back into range.

https://antiqueradio.org/art/Emerson609TelevisionWidthExperiment.jpg

I guess the guy who added that cap was onto something :)

There's more tweaking to do -- there is still a very slight crushing of width on both far edges -- but I have a watchable picture for the first time in this project.

https://antiqueradio.org/art/Emerson609TelevisionDamperResistorReplaced.jpg

Yay!

Phil Nelson
Phil's Old Radios
https://antiqueradio.org/index.html

EdKozk2
06-20-2018, 12:48 AM
Hi Phil,
Your picture looks really good now.:thmbsp:
Ed

irext
06-20-2018, 12:58 AM
I've been watching this thread with great interest. Very well done. Just goes to show "never give up". Working rear projection sets would have to be as rare as rocking horse poo.

decojoe67
06-20-2018, 04:45 AM
Very nice work. Interesting to see how these sets performed. They must've really impressed people back then with their, for the time, huge picture.

old_coot88
06-20-2018, 09:34 AM
:D:banana::banana:

Phil you da man.

jr_tech
06-20-2018, 11:29 AM
Wow, lookin good! :thmbsp::thmbsp::thmbsp:

Do you intend to experiment with other values of R-86 to address the slight crushing that you observe?

jr

old_tv_nut
06-20-2018, 11:52 AM
Always great when black magic turns into problem solved!
Looking very watchable!

old_coot88
06-20-2018, 12:52 PM
...rare as rocking horse poo.
Gotta 'member that one. :lmao:

Phil Nelson
06-20-2018, 12:58 PM
Do you intend to experiment with other values of R-86 to address the slight crushing that you observe?Unfortunately, I don't have an assortment of 25-watt resistors on hand. I had to mail-order the replacement that I used.

The symmetrical edge crushing is slight, but noticeable with a test pattern. In a crosshatch pattern, the edge-most two or three columns of squares are narrower than the rest.

Any guess as to what range of values might be reasonable to experiment with? The stock resistor is 7.5K. One local store sells 25-watt resistors in values as high as 5.6K. For an experiment, I can wire resistors in series to make other values, of course.

Phil Nelson
Phil's Old Radios
https://antiqueradio.org/index.html

old_tv_nut
06-20-2018, 01:13 PM
Does the .25 cap affect both overall size and the edge squeeze? If I follow what's happening, will you need a joint adjustment of the cap and the resistor for best overall result?

Phil Nelson
06-20-2018, 01:25 PM
I didn't keep a library of screen photos while testing, but I believe changing the .25 cap value did affect the squeeze somewhat, to a lesser extent than the width.

Experimenting with both the cap and resistor values is a possibility, if I get a little assortment of 25-watt resistors to play with.

Phil Nelson

jr_tech
06-20-2018, 01:57 PM
For a quick test you could bridge the 7.5k with a much lower wattage resistor, perhaps starting with something like 20 to 50k and observe the change (if any). Also a lower wattage resistor, something like 500 to 1000 ohms could be added in series for a quick test. :scratch2:

jr

old_tv_nut
06-20-2018, 03:09 PM
You can't do it with the high wattage components, but if it were lower power, simultaneous adjustment with both a capacitor decade box and a resistor decade box could make short work of a problem like this.

This has been deprecated in the past as "dec-box engineering" because there is no pre-calculation of the correct values. But it need not be looked down on if two things are true:
1) You already have a reasonable starting point
2) You are observant enough to understand which aspect of performance is changing as you make the adjustment.

In a hypothetical example, you might note that a small resistor change modifies overall width (and is it larger or smaller) without much change in edge compression, while the cap affects both width and compression, and adjust first the cap in a small step to get better edges, then the resistor in a compensating small step to get the right width, and so on.

NOTE: you also have to be aware whether the transient condition of an open circuit while switching the dec box could cause a destructive fault. In your case, you already know nothing is being destroyed even with the components open-circuited.

old_coot88
06-20-2018, 10:37 PM
Phil, it might be worth trying the old "seven seconds off & back on" test. Does the raster come back at full width, or is it slow filling out? If unusually slow, are there any peculiarities with the lin during fill-out?

old_tv_nut
06-21-2018, 10:52 AM
Phil, it might be worth trying the old "seven seconds off & back on" test. Does the raster come back at full width, or is it slow filling out? If unusually slow, are there any peculiarities with the lin during fill-out?

This is interesting to me. Does slow recovery point to weak tubes or other things as well?

old_coot88
06-21-2018, 11:50 AM
This is interesting to me. Does slow recovery point to weak tubes or other things as well?
Exactly. It's an old 'quick & dirty' field test for borderline-weak tubes like hor osc and 3.58 osc. (slow achieving sync), hor. out (slow fill-out), vert. out (slow fill-out), RF amp (slow clearing snow), etc.

Same principle as the Life Test on a tube tester which drops the heater voltage down.

This was followed by the 'tap test' of each tube to show up any arcing (like the damper), intermittent shorts etc.

Made service calls more effective with less chance of call-backs.

Phil Nelson
06-21-2018, 02:20 PM
OK, I'll try the seven-second test later today and observe the results.

I spent some time yesterday playing with different values for R86, using a handful of 25-watt resistors that I picked up locally. It is a cumbersome and very slow process, to clip a resistor (or series-ed resistors) into place, slide the chassis back into position, turn the set back on, observe the result, and try to compare the pattern to what you saw before. I tried taking photos with the camera on a tripod, and noting the resistor values for later comparison.

Subbing the capacitor values was so much easier with a decade box, where I could keep my eyes on the screen and flip between different values, back and forth, looking at different parts of the screen, etc.

Anyway, yesterday's results were not very informative. When I put a crosshatch pattern back on, I realized that the linearity wasn't quite as good as I remembered.

I also realized that I had begun with the TV in a somewhat random state -- that is, with the various controls set to produce an image with best horizontal linearity & centering. I had also left in the .22 cap across the width coil. What kind of baseline is that? Perhaps it would make more sense to remove that .22 cap and center ALL of the pertinent controls, then repeat the rigamarole of subbing the cap and resistor values, looking for changes that make sense.

There are lots of variables in this equation. In addition to the horiz width and linearity adjusters, you have the horiz centering and horiz drive adjusters, all of which affect width and linearity to some extent. Not to mention the mechanical centering adjusters on the optical box.

Does anyone have a clear idea what changes you would expect to see on a perfectly-linear set when changing the value of this damper resistor (R86)?

Phil Nelson

Electronic M
06-21-2018, 05:49 PM
Does anyone have a clear idea what changes you would expect to see on a perfectly-linear set when changing the value of this damper resistor (R86)?

Phil Nelson

On a perfectly linear set no. I did mess with that and parallel capacitance on a Hoffman that had width and linearity issues a year or two ago.

Some sets that used that big damper resistor (RCA 630?) had taps on the resistor to rough in one of the horizontal adjustments (forget if it was the width or lin) so the control of that name would be in the correct range to work.

Phil Nelson
06-21-2018, 11:57 PM
Some sets that used that big damper resistor (RCA 630?) had taps on the resistor to rough in one of the horizontal adjustments (forget if it was the width or lin)Yes, now I recall seeing a tapped damper resistor in one of my old TV books.

The 630TS factory manual says this is a coarse linearity adjustment:

"If repeated adjustments of drive, width, and linearity fail to give proper linearity, it may be necessary to move the tap on R209, which is located in the high voltage compartment. Adjustments of drive, width, and linearity must then be repeated."

The parts list describes R209 as:

"Wire wound resistor, 5300 ohms, 20 watt; 500 ohms, 2 watt; and 500 ohms, 2 watt."

Not sure what to make of that description. Why only 2 watts for the 500-ohm segments?

In the schematic, that resistor is drawn with three taps, and the default connection made at the center tap. I interpreted this to mean it's a 5300-ohm resistor, which you can adjust to either 5800 or 4800 ohms by moving the tap. Am I guessing wrong about the resistor construction?

Phil Nelson

old_coot88
06-22-2018, 12:15 AM
The parts list describes R209 as:

"Wire wound resistor, 5300 ohms, 20 watt; 500 ohms, 2 watt; and 500 ohms, 2 watt."

Not sure what to make of that description. Why only 2 watts for the 500-ohm segments?

Assuming a constant current through the resistor, a 500 ohm section will have roughly 1/10 the voltage drop across it as the 5300 ohm section, hence 1/10 the wattage (actually it'll be slightly less than 1/10).

(If the 5300 were 5000, the figures would be exact.)

Tom9589
06-22-2018, 08:01 AM
[QUOTE=
The parts list describes R209 as:

"Wire wound resistor, 5300 ohms, 20 watt; 500 ohms, 2 watt; and 500 ohms, 2 watt."

Not sure what to make of that description. Why only 2 watts for the 500-ohm segments?
[/QUOTE]

Power in each segment uses the formula P=(I^2)R. Since the resistor section are in series, the same current would go through all resistor sections. The 500 ohm sections are approximately 1/10 the value of the 5300 ohm section; hence, their power handling capacity would need to be only 1/10 the wattage of the 5300 ohm section.

old_tv_nut
06-22-2018, 11:01 AM
I think it means the first section is 5300, in series with a 500 and another 500, so total is 6300. Power is I squared times R, so if the current is approximately the same magnitude for all settings, the smaller resistors in the series string need proportionally smaller wattage. So, one tenth the R --> one tenth the watts.

Phil Nelson
06-22-2018, 12:57 PM
Ah, another forehead-slap moment. Lower resistance means lower wattage, duh.

I reviewed the photos that I took while experimenting, and it's clear that increasing the resistance stretches the left half of the image, while decreasing resistance squeezes the left half.

Changing the resistance also changes the overall width somewhat. And it does not really cure the non-linearity I'm seeing. The far left edge is still squeezed, etc. And there is an additional variable -- the value of the .22 cap added to increase the overall width.

Finding the best setting looks like a very iterative process:

-- Try new resistor value
-- Adjust the width, horizontal linearity, and horizontal drive controls for best linearity
-- Try another resistor value
-- Adjust all the etc.
-- Repeat, repeat (maybe also adjusting the value of the .22 width-coil cap to see how that effects everything)

That would be simpler with a direct-view TV, which you could plop onto the workbench and easily view while adjusting. Not so much fun when you are crouching on the floor to make adjustments and peering around to view the results in a little serviceman's mirror on the other side of the cabinet.

OK, enough whining already! I hope to make some progress this weekend.

Phil Nelson

Phil, it might be worth trying the old "seven seconds off & back on" test. Does the raster come back at full width, or is it slow filling out? If unusually slow, are there any peculiarities with the lin during fill-out?

P.S. I did try the seven-second test suggested by old_coot88. The raster comes back at full width. You can hear that the HV spools up slightly after everything else, so there's a brief interval with no raster. But when it reappears, the image is at its full width.

Electronic M
06-22-2018, 03:35 PM
Ah, another forehead-slap moment. Lower resistance means lower wattage, duh.

I reviewed the photos that I took while experimenting, and it's clear that increasing the resistance stretches the left half of the image, while decreasing resistance squeezes the left half.

Changing the resistance also changes the overall width somewhat. And it does not really cure the non-linearity I'm seeing. The far left edge is still squeezed, etc. And there is an additional variable -- the value of the .22 cap added to increase the overall width.

Finding the best setting looks like a very iterative process:

-- Try new resistor value
-- Adjust the width, horizontal linearity, and horizontal drive controls for best linearity
-- Try another resistor value
-- Adjust all the etc.
-- Repeat, repeat (maybe also adjusting the value of the .22 width-coil cap to see how that effects everything)

That would be simpler with a direct-view TV, which you could plop onto the workbench and easily view while adjusting. Not so much fun when you are crouching on the floor to make adjustments and peering around to view the results in a little serviceman's mirror on the other side of the cabinet.

OK, enough whining already! I hope to make some progress this weekend.

Phil Nelson

My favorite way to think of it is if you want to replace a 5000 ohm 10W with a series pair of 2500 ohm units those need to be 5W a piece, if you want to replace with 4 1250 ohm 2.5W a piece, 8 625 ohm units at 1.25W each and on down*...If your changing the main resistance only slightly things should be safe doing the calculations based on the present current/voltage going through it, but if you change the resistance a lot the current flow may change enough to require recalculation of wattage.
*My college only stocked 1/2W resistors so when the maths for a circuit design called for a 10W+ resistor that needed to last 30min of various measurements and tests without burning up we had to get creative with series-parallel combos to get a safe wattage...And the professors and parts room folks always wondered why there were so many off tolerance resistors in stock. :screwy:

What kind of connectors does the main chassis use to hook into the cabinet projection system?... If it is just a set of octal and or Fat-pin tube base/socket connectors (and maybe a CRT socket/HV lead) why not make 5'-12' extender cables so you can keep the cabinet next to the bench and have the chassis on the bench connected to the cabinet for easy adjustment and testing....I did just that when I was working on my 21CT55 to make things easier for me.

Phil Nelson
06-22-2018, 11:15 PM
Extender cables would be handy, although not super-easy.

Two of the three cables would be do-able. The yoke connector is 9-pin, roughly the size of an octal socket with a ninth pin near the center. A second cable goes to the HV power chassis with a 4-pin connector. I don't have such connectors on hand, but I suppose you could scrounge them somewhere.

The CRT cable looks tricky. It uses a funky 5-pin connector of a type I haven't seen before. The cup has terminals on the inside and it slides over the butt end of the CRT, which has little metal tabs around its edge.

https://antiqueradio.org/art/Emerson609TelevisionCRTConnector.jpg

Weird,wild stuff, as Johnny Carson used to say.

You wouldn't need an extender for the HV cable to the CRT second anode, since that doesn't come from the main chassis. It only goes between the two boxes of the Protelgram unit (HV power chassis and optical box holding the CRT).

Phil Nelson
Phil's Old Radios
https://antiqueradio.org/index.html

Electronic M
06-22-2018, 11:56 PM
CRT base appears to be a euro tube connector...I once was at a swapmeet where someone had some really old Brittish or German tubes with that style of connector...Some had a different number of 'pins'. I had the same impression when I saw them there for the first time...

In your shoes if I did not much like the set, badly wanted/needed service convenience, or had a situation where the wiring to the interconnects was damaged or otherwise unoriginal I'd be tempted to cut the harnesses and insert some other connector that I could easily make (or use an existent) extender for...In any case it's your set, your back/knees, your call.