My tubular HV caps arrived and I've spent the last two days finishing (I hope) the chassis work. I replaced or repaired everything questionable. Most of the previously replaced components would have worked, but the solder joints had to be redone and the leads had been cut too short for proper placement.

https://lh4.googleusercontent.com/-pycHTHJ1bew/UFQLNE8TZfI/AAAAAAAAKD0/PbUJL53pkDc/s800/Job%25201%2520Done.jpg

Several circuits had been modified. Since I don't have the expertise to assess the functionality of those modifications, I tried to put everything back to agree with the schematic. You might understand why the circuits had been changed, but I haven't got a clue. This shows the previous modifications in red and my reconstruction in blue:

https://picasaweb.google.com/lh/photo/P-mr7FHEBTIS2ikbLFpypdMTjNZETYmyPJy0liipFm0?feat=dir ectlink

I don't have a Variac, so I hid behind a chair when I powered it up. Nothing exploded, no flames, no smoke, and after a minute of warm up, this image appeared.

https://lh3.googleusercontent.com/-0b_74VyfcN8/UFNeXX6WQeI/AAAAAAAAKCI/kccZigJ7vFU/s640/felix.jpg

Well, OK…that image didn't appear. I was delighted to get anything on the CRT, and with my test pattern videotape this is the best I could do:

https://lh3.googleusercontent.com/-UBd4SZYfH6g/UFPKqyYoNvI/AAAAAAAAKDg/fhCZUIRMpL8/s800/17T12%2520CRT%2520Image%2520091412%25201.jpg

There actually is an image in there. With a movie video I can see ghosts moving around. I feel some satisfaction in taking it this far. Nevertheless, I'd like to improve the picture.

Any suggestions about what I should next?

- Winky

Looks like you should try adjusting the H & V hold controls to see if you can lock the picture in. Once you do that you can try the other controls on the back to get everything to look like it does in the test pattern.
Your work under the chassis looks good.
Good Luck,
Cliff

It looks like your horizontal frequency is off, you have multiple pictures side by side.

I don't know if the 17T12 has a fine horiz frequency coil or not, I don't see one on the ETF schematic but if it does adjusting the slug may bring it into range.

If the only horiz frequency control is the horiz hold pot then you may have a component out of spec like a badly drifted resistor or you have put the wrong value cap in the horiz oscillator circuit, i.e a .01 where a .001 should be (done that more than once).

Thanks. I did exhaustive adjustments of all nine pots to achieve this result. I'll look for wrong value cap first, reading and checking values against the schematic, then rechecking values with the multimeter. Then, regarding the horiz frequency, I see what I can figure out from the alignment instruction.

Appreciate the help.

- Winky

Houston, we have Lights...(grin)

Yah, the horizontal frequency is way off, but you may be closer to a coherent picture than you think.

Your horizontal circuit is much like the 19A12 that I recently finished. The manuals say little or nothing about adjusting horizontal frequency because there is nothing to adjust, apart from horizontal hold and horizontal size. This simple circuit does not have a coarse frequency adjuster, horizontal drive adjuster, etc., such as you'll find in fancier TVs.

The best you can do is to make sure the components are correctly connected and have the right values. I replaced several resistors in that area, perhaps a couple more than absolutely necessary, but now the horizontal works well.

Interesting parts to check: R42, R43, R44, C36.

In addition to the Wallace Teleaide schematic from ETF, you can look at the Riders 19A1 manual there. It uses the same part numbers as Wallace.

Originally, the output of the sync amplifier was coupled to the horizontal oscillator with a single capacitor. Riders describes a sync filter circuit that was inserted in place of that cap for later versions (C61, C62, C63, R90, R91, R92). If your set has that circuit, those components are candidates for checking. If the signal coming from the sync amp is distorted, the horizontal oscillator can't work correctly.

Riders also says that C37, a .001/1KV mica cap, is there for horizontal "symmetry and wave form correction." Another one to check. Micas are reliable but they do break down sometimes.

On the positive side, a simple circuit has fewer components to check than a complex one. You may be very close . . . .

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

It seems pertinent that the one adjustment that gave me a barely discernible image was the horizontal hold--and it had to be close to full rotation in one direction or the other.

Coincidentally I was checking C37 this morning. Couldn't get a reading without taking it out of the circuit and was reluctant to desolder it. But I will tonight.

I also located all the coil screw thingies (you call them slugs) and noted which sections they worked with.

I'll look over the Rider 19A1 manual and see what I can figure out.

Thanks,
Winky

I checked out everything Phil mentioned, including the sync filter circuit, and I took all the components out of the circuit for testing. Everything checked out pretty close to the specified values. I reassembled it all and, just for grins, replaced the horiz oscillator 6SNGT with a spare NOS tube. This is what I got:

https://lh5.googleusercontent.com/-COKkzcyrsig/UFaLtMH2g9I/AAAAAAAAKEE/-y-bvS-y2X8/s800/2012%252009%252016%252017T12.JPG

You're looking at Lee J. Cobb. Or maybe it's Henry Fonda? Well, it's one of those 12 Angry Men.

This is better than the previous picture, BUT…then it started going out of focus, and randomly flickering into focus every few seconds. And now it's remaining unfocusable.

Is there any point in fooling with the alignment without equipment or knowledge?
Gee, I wish Mr. Grimes was here.

- Winky

Don't mess with alignment. Without proper equipment (and expertise), that would likely make things worse.

Have you double-checked every one of your replacements against the schematic? It is distressingly easy to make a wiring mistake. Everyone reading this thread has done it at one time or another. A wiring error can sometimes create a weird symptom that's hard to debug. Instead of the classic repair situation where you're trying to track down a failed component, you may have a case where every component is good but you accidentally connected the neckbone to the kneebone.

Incidentally, if you are checking capacitors, they need to be checked at their normal working voltage. A modern digital multimeter can't apply enough voltage for a meaningful test. My cap checker only works up to about 500V, so for anything beyond that -- say, the 1KV rated cap mentioned earlier -- the only way I can test it is by substitution: installing a new one.

Phil Nelson

I recognize that my multimeter capacitor testing isn't good for much other than confirming a nominal value. I thought about trying to substitute for the 20pF caps, but the best I could do with materials on hand was 50 .001mfd caps in series. I ordered an assortment of 10pF-500pF caps today.

I think the focus problem is fixed. A focus pot lug was nearly touching a lug on the adjacent pot. I pushed them apart and ran the set for 30 minutes with no focus problem.

I rechecked my circuits multiple times, but if I've done something that I thought was right the first time, then it's hard to recognize it as an error. I'll try tracing the circuits backwards from the way I would usually look at them. I may even experiment with reversing some of my "corrections."

Thanks for addressing my many issues.

- Winky

Last night while puzzling over what could do bad things to the horizontal frequency, I made a fortuitous accidental discovery. While checking some voltages I inadvertently touched the probe to the case of the horizontal centering pot and heard a "Zap!" Yup, the metal cases of both the horizontal and vertical centering pots were energized with big voltage.

https://lh6.googleusercontent.com/-39xSXpV8Fr0/UFi22N9ZJmI/AAAAAAAAKEc/aeDjT8x2-Bw/s640/17T12%2520H%2520Cent%2520Pot%2520Short.jpg

I disconnected and removed both pots, on the horizontal pot found a short between a lug (not the wiper) and the case. Couldn't see anything wrong on the outside. Disassembled the pot expecting to find a stray big of solder or wire fragment. Didn't find anything.

https://lh3.googleusercontent.com/-CUAE_9UtJb0/UFi2zbGltgI/AAAAAAAAKEU/1HOCJZVdJqk/s640/17T12%2520H%2520Cent%2520Pot.jpg

Reassembled the pot, and there's no short, and the resistance range seems to be a normal 100 ohms to 1.9 Meg. So I'm gonna put it back together and see how it works.

BUT…the wiper lug is about to break off. It would be difficult to fix it in its normal position, but could I just solder it to the metal case? The metal tabs on the case are continuous with the wiper terminal, so if I soldered one of the tabs to ensure a good connection, then I could use any part of the case for the wiper connection. Would that work?

- Winky

Put a new wiper lug on the horizontal centering pot, then reassembled and reinstalled both the horizontal and the vertical pots. Checked that there were no shorts between the wipers and the other terminals. Hoped that this would somehow cure the horizontal frequency problem, but no-o-o-o! And then I checked the pot cases and found that they're still hot. Bummer! I assume the metal cases should shoot sparks when they're grounded, but I can't find anything wrong with the circuitry.

https://lh5.googleusercontent.com/-_aZAoYzJgPc/UFuW15HKVrI/AAAAAAAAKEw/RYGHFc1O-PI/s640/17A12%2520Pot%2520JB%2520Weld.jpg

Other than retracing all the circuits for the fortieth time, I'll try switching out one or more of the presumed-good mica caps. I don't have the parts for that yet, but I expect the dog sled from Just Radios to arrive any day now.

- Winky

Perhaps those pot cases are hot by design. That would explain why they're mounted on an insulating phenolic board rather than on the metal chassis. The nylon shafts also insulate you from Bzzzt.

Mica caps can and do fail, especially in high voltage and/or high frequency situations.

Phil Nelson

I'm constantly amazed at my own ability to overlook the obvious. And I just rechecked the focus pot which I thought wasn't hot--but it is hot, too.

Thanks,
Winky

The more I fix it, the broker it gets. When I fried the horizontal size pot I noticed that I'd lost some horizontal dimension--couldn't get it to fill the screen. I thought the horizontal size would go back to normal when I replaced the pot. But after the replacement the size continued to diminish. The next time I powered up the set, the horizontal size was even narrower. I started rechecking voltages and found that the low voltage rectifier filament was getting no voltage (previously it was 275 VDC as specified).

https://lh4.googleusercontent.com/-wZ9alqospVs/UG05K7sb5UI/AAAAAAAAKGE/i_NKHXHC5mQ/s640/T6%25205Y3%2520Schem.jpg


So I guess I have a problem with the transformer. I hadn't noticed before, but the transformer is missing four out of six bolts, so maybe someone has taken it apart before.

https://lh6.googleusercontent.com/-fp_eBhtU_r8/UG061gs6_xI/AAAAAAAAKGM/v7-0IVzjT0g/s640/T6%2520Screw%2520Loose.JPG

So, I'm requesting advice on these questions: Why did the transformer fail? Is it worthwhile to disassemble the transformer? Is there anything fixable inside? Is there a work-around for a single dead secondary coil (keeping the other two functional)? Finally, should I just go back to working on radios? I have a nice Atwater Kent that I haven't broken yet.

For background, this is a link to the full schematic which shows the wiring as I found it in red and my rewiring to conform with the original schematic in blue.

https://picasaweb.google.com/lh/photo/P-mr7FHEBTIS2ikbLFpypdMTjNZETYmyPJy0liipFm0?feat=dir ectlink

Always appreciative of your guidance,
Winky

'Scuse the dumb question, but is the 5Y3 filament lighting up?

I'd like to just say, "um-m, nevermind." But to take full credit--yes, the filament lights...and I just misread the instructions and was looking for 275 V across the filament instead of 5 VAC. Now I'll go back and look for the horizontal size and see if I can find out what smell like it's burning before my wife walks by and asks, "Are you burning something?"

Thanks much.
Winky.

Speaking of horizontal, weren't you going to replace a mica cap or two in that area (C37, C39, perhaps)? Or maybe that has already been done . . . .

Phil Nelson

I got to the point where all my "fixing" was just introducing new errors, so I walked away from the project for a few days. In fact, I was going to drop this project and move on to something else, but, "As soon as I think I'm out, it pulls me back in." I can always find one more thing to try.

Yes, (Phil) I did try replacing those mica caps. Due to an unfortunate lapse of attention, I forgot they were 1KV caps and I replaced them with 630V caps. That's how I burned up the horizontal size pot. I have since replaced both the caps and the pot.

Then I made one last change in the wiring. My set, Phil's recently restored 19A1, and the Sams 19A1 photo all show this connection to the horizontal size pot, so I left it like that even though it didn't agree with my 17T1 schematic.

https://picasaweb.google.com/lh/photo/olL5SHHmRYD7dw8A6idjk9MTjNZETYmyPJy0liipFm0?feat=d irectlink

That's how it is in the Sams schematic, but the Wallace and Riders schematics are different, so I rewired it according to the Wallace 17T1 schematic.

https://lh6.googleusercontent.com/-eOulKhxbWHI/UHSDlrAvDuI/AAAAAAAAKGc/btK23KTwRIk/s640/001%2520Sams%2520R41%2520R55.jpg

The outcome didn't change much even though I imagine I can see a better image. It still comes up short on horizontal size.

https://lh6.googleusercontent.com/-UhIO0Sa-OtM/UHSDomQbsuI/AAAAAAAAKHA/nVD97VXX4MI/s640/001%2520Screens.JPG

I think I'm done replacing caps and resistors and I've rewired to entirely conform with the schematic. Now I have to ask about the significance of these voltage readings (actual voltage in red). My last bit of rewiring from the sync amp plate (pin 2) reduced the voltage from 125V to 77V. I have no idea if the voltage variance from the HV rectifier (corona ring) to pin 5 on the HV oscillator means anything at all.

https://lh5.googleusercontent.com/-xFo8cVAMZEk/UHSDrZlHMeI/AAAAAAAAKG0/DiGHUePam98/s640/001%2520V11%2520V12%2520Anomalies.jpg

Anyone have a clue what could be doing bad things to the horizontal hold and horizontal size? Here's a link to the full schematic:

https://picasaweb.google.com/lh/photo/6CIqfCBNDwq1g-Jx08_pvtMTjNZETYmyPJy0liipFm0?feat=directlink

Is it time to put this set back on the shelf? Thanks for your attention.

- Winky

I'd check the resistors and caps and coils between the first 6SN7 triode V11A (of the diagram in your post) and the video amplifier tube. The sync signal may be getting lost or too weak between these tubes.

Examining the sync may be worthwhile. Your most recent photos look like you have both vertical and horizontal problems. The image is repeated horizontally (wrong frequency) and the vertical looks stretched out, with too much space between lines.

Compare this photo of my RCA 721TCS at a point when I was partly done recapping.

http://antiqueradio.org/art/RCA721TCSFirstPicture.jpg

That case also showed the image repeated horizontally, with the images stretched too far vertically. Notice how much space there is between scan lines.

The sync section affects both vertical and horizontal, so it may be a logical place to start, as wa2ise suggested.

Phil Nelson

Thanks. I'm working on it.
- Winky

As advised, I've checked every cap, resistor, and coil from the sync separator through the horizontal and vertical output. I also replaced several mica caps just because I had no way to test them. Everything there seemed to be OK, so I continued the testing back through the video amp and video detector and found one peaking coil to be defective.

https://lh3.googleusercontent.com/-J5lzp5Rb9zY/UHvRXe12ZgI/AAAAAAAAKIQ/-hnXrIsJZWA/s640/L8%2520schem.jpg

If you look close, you might see what the problem is:

https://lh6.googleusercontent.com/-BmnLPp6MlWY/UHvChwO7GKI/AAAAAAAAKH4/g_iND3fTQYg/s800/L8%252012Kohms.JPG

I don't think that has anything to do with my horizontal/vertical sync problem, but I'll fix it anyway. The resistor looks to be 50% too high, so I'll replace it as well. It's a 516 uH coil, and Mouser a 510 uH axial rated for max 124 mA (is that enough for this application?). I managed to get my meter leads across the coil, and it's still about 16 ohms, so I'll attempt to repair it. I only have about 1 millimeter of coil lead to work with, and it's very fine--maybe 600 gauge. I have an idea how to do this, but does anyone have suggestions on microsoldering?

https://lh5.googleusercontent.com/-R7qz-66TKjI/UHvRVxymw3I/AAAAAAAAKII/fMLqyFFpqa0/s640/L8%2520Size.JPG

Back to the horizontal/vertical sync: I picked another couple of used 6SN7's, and I'll switch them out just to see if it makes any difference. My understanding of the electronics doesn't go much beyond replacing components, so I hired a gnome to help me out.

https://lh5.googleusercontent.com/-bEnv3HthSck/UHuGIYB8v7I/AAAAAAAAKHo/R7_TM-UnmTo/s640/Nipkow%2520Gnome.JPG

He tells me that the sync amp inverts the signal to correct polarity. Could polarity or out-of-phase error cause my kind of problems? The gnome seems to know what he's talking about, but he hasn't shown me any credentials.

Video output is not your major problem, but as long as you found this bad coil, you may as well deal with it.

I am not an expert on soldering very fine wires, but I have succeeded with caveman technique a couple of times. Sacrifice an old cable like a microphone or headphone cable that has very fine stranded wire for shielding or whatever. Use one strand to bridge between those stubs. Wrap each end of the bridging wire a few times around the stubs using a tweezer or jewelry pliers. Don't heat the joints any longer than needed to flow the solder.

It may not be beautiful and it won't survive a hard yank, but if you can make a secure connection between those stubs, it should work. I wouldn't worry about insulation until you know whether it works. Later on, you can dab some liquid tape or corona dope on the bare wire, if you like.

Re the horizontal/vertical problems, previously, I puzzled over the modifications done by your previous owner and didn't really see what he was driving at. (Who knows, maybe he didn't, either.) When someone has done modifications or made oddball repairs, there's always the possibility that he did one more Weird Thing you haven't yet noticed.

You have a reasonably bright image (thus, some HV and not-too-awful video output). A signal is getting through the RF and IF stages. You have vertical and horizontal deflection. But both the vertical & horizontal sweep are out of whack, so either you have two problems, one in each sweep section, or possibly one problem in the sync stage that feeds both of them.

This should not be that hard. Some test instruments (oscilloscope, generator that can supply horizontal & vertical drive signals) would simplify debugging, but that's empty advice if you don't have such gizmos.

Yo, smart people -- any ideas?

Phil Nelson

I've done everything within my capabilities for the Admiral 17T12, so it goes back on the shelf until I gain some sophistication in technique and equipment.

In the meantime, I'll get back to the Atwater Kent Model 37.

Just for grins and giggles, I repaired the broken peaking coil. It took a couple of hours, but I saved the $1.75 I would have had to pay for a new inductor from Mouser.

https://lh6.googleusercontent.com/-X77nR6Ax1Fs/UH45oz98_tI/AAAAAAAAKIk/QWhF0jYSJTE/s640/L8%2520Repair%252001.JPG

https://lh5.googleusercontent.com/-SzuhgAhe3p8/UH45sd0p-qI/AAAAAAAAKIs/YKUdAQMkAGM/s640/L8%2520Repair%252002.JPG

https://lh6.googleusercontent.com/-eVxX9WO6geI/UH45v3BcpSI/AAAAAAAAKI0/e63kUfUbK_g/s640/L8%2520Repair%252003.JPG

Added 33K resistor parallel to get resistance, now 12K, close to the specified value of 8.2K.

https://lh3.googleusercontent.com/-2fernzjHbBM/UH-WoiUVf0I/AAAAAAAAKJI/JGJ1pD1NopY/s640/L8%2520Repair%252004.jpg

Sincere thanks to everyone who helped me with the Admiral. Even though it's not yet a success, it's been fun. If anyone is driving through Boise and happens to have an oscilloscope and a generator in the back seat, please give me a call.
- Winky

Winky Dink,
I am working on a 19a1 set and had the exact same screen you had. I could get a 3 inch wide image with careful adjustment but anything else caused it to break up horizontally and then it looked like yours. Turned out these sets are sensitive to the type of 6sn7 you put in. Mine doesn't like the two new testing GE 6sn7GTB's it had. 2 old used 6sn7GTs made the sweep work fine.
Also, if you want to test the horizontal sweep circuit without the sync components there is a cap that goes across V12. It is labelled as C35 and goes across pins 2 and 4. If you disconnect this cap you will let the horizontal run free (no interference from the sync circuit). This should result in a full horizontal sweep that you can momentarily sync using the horizontal hold. It would be a good way to make sure that the horizontal circuit is working OK without the sync input.
Hope this helps.

Did you ever check the resistance on the T3 blocking transformer? You have to lift (and I recommend replacing) the resistors. This transformer and C36 (double check that it is .01) seem to set the basic frequency of the horizontal circuit.
After I changed all the resistors in the horizontal circuit (there are only 3 or 4 fixed resistors) the horizontal hold and size are nicely centered.

How do the voltages and resistances check out? That could quickly highlight areas of failure and monkeywork.

1. Thanks for the guidance.

2. I just got a couple of used 6SN7's, both GE, which I will try tonight.

3. Regarding T3: The Sams numbering is different than the Rider or Wallace Telaides. I assume this is the transformer between the sync amp and horizontal oscillator (Rider T3). I have lifted the 39K resistors, and they check out OK, and the resistance across the coils is also right.

https://lh5.googleusercontent.com/-xFo8cVAMZEk/UHSDrZlHMeI/AAAAAAAAKG0/DiGHUePam98/s640/001%2520V11%2520V12%2520Anomalies.jpg

The voltages at V12 pins 2 and 4 don't look right, but I don't know what that means. Even though all the resistors in the horizontal circuit are within 10% tolerance, I'll replace them as David suggests because, if nothing else, I enjoy the soldering.

4. The C35 linking V12a and V12b has been replaced in my model with this chain.

https://lh5.googleusercontent.com/-c2dmXd39EiY/UIC5jNC8rBI/AAAAAAAAKJw/5bM4Kj9NrVA/s640/V12%2520A-B%2520link.jpg

Even though the caps are ceramic, I replaced them just in case.


5. After doing the above, I'll experiment with disconnecting the sync. I say "experiment" because I don't know what to expect--I'll just play with it and see what happens.

Just because Phil mentioned the oscilloscope, I'm showing this photo with the sine wave down the middle--interesting because it's not visible when watching the screen, but is captured with the digital camera. All of this reminds me of the first episode of the original "Outer Limits."

https://lh6.googleusercontent.com/-b0GXicu8n04/UIBmqRZoD0I/AAAAAAAAKJk/KPn43XhQE7s/s640/O-Scope.JPG

Thanks again,
Winky

Bummer, dudes. Disconnecting the sync did nothing--same restricted horizontal sweep and could not not sync with horizontal hold. Replaced the transistors in the sync-horizontal oscillator link and on T3 and anything else I thought was in the horizontal sweep arena. No change except (and this is a little wierd) now when I adjust the vertical hold, in addition to stopping the vertical roll, it changes the vertical dimension just like the vertical sizer control.

Failure of horizontal sweep with the sync disconnected--does it mean something?
-Winky