Hello VK'ers. Man has it been 5 years? Glad to see membership here is free now. I really liked this forum but couldn't afford to renew... I still have the CC II that Strawman gave me.

Well I'm back with a curb find, a Motorola black and white tube TV, made in 1965. I found it curb side, not sure if it works, don't have a variac to plug it into.

I think the set might have low hours on it. I say that because I took the tubes out to clean them up one by one, and some of the tubes are Motorola tubes, maybe the original ones.

Trying to find out a bit more about this set, see if there's anything interesting about it.

Nice find !! All tube set--cold chassis too. Motorolas are NOT all that common after the 1950's..
A keeper for sure

"All 82 channels". Man, that's gold. Great save.

I'm debating whether to put in the time to restore it or find somebody to just give the set to. I don't have things like a tube tester or a variac, and I don't really have much use for a Black and White tube TV. Yeah it's a good conversation piece but I have enough of those.


If I went the restore route, would it be worth the time and besides the wax capacitors, what work would need to be done? I think the UHF dial hasn't been used in decades, it's difficult to turn and it takes several turns before the channel numbers move. VHF dial feels normal.

I'm debating whether to put in the time to restore it or find somebody to just give the set to. I don't have things like a tube tester or a variac, and I don't really have much use for a Black and White tube TV. Yeah it's a good conversation piece but I have enough of those.


If I went the restore route, would it be worth the time and besides the wax capacitors, what work would need to be done? I think the UHF dial hasn't been used in decades, it's difficult to turn and it takes several turns before the channel numbers move. VHF dial feels normal.
The set's new enough to have Mylar capacitors, instead of wax and paper capacitors.
I would try the set and see if it needs further work. The sets were as good as the Zenith offerings of the time. :thmbsp:

I sure like the looks of that, inside and out! Great save.
Kevin

The set's new enough to have Mylar capacitors, instead of wax and paper capacitors.
I would try the set and see if it needs further work. The sets were as good as the Zenith offerings of the time. :thmbsp:


All right... Say a prayer. I'm gonna plug it in and see what happens...

OMFG!! It's alive!!

http://i.imgur.com/kcGwIWn.jpg

(Apologies for crap picture. My phone died, so now I'm using a much cheaper phone with a much cheaper camera.)

So, turn it on, channel indicator lights up, about 30 seconds later sound comes on, another 30 seconds and I got a picture.

So does this mean I can run it for a bit? Maybe hook up a video source and see how it does?

If nothing smells hot you should be Ok, just dont leave unattended.

Amazing catch! It'd be a good idea to feel that big filter can in the upper right-hand corner to be sure it's not heating up.

Right. I'm going to run it for a few minutes. It's connected to my power strip so if it starts doing anything funny I can cut the power instantly.

Gonna go hook my DTV box to it.

Edit: Well, it works better then I expected a 50 year old TV that I found on a curb to work. Vertical hold knob is either missing or broken.

http://i.imgur.com/VjEoYSp.jpg

http://i.imgur.com/T6bsUkn.jpg


And the camera in this phone is so cheap that green horizontal lines randomly appear in some of the pictures it takes. :thumbsdn:

Knobs need deoxit badly. Sound is fine, except the audio gets randomly scratchy... again, probably due to dirty knobs, and I need to see what's going on with the vertical control. Other then that it works.

So yeah... 50 year old TV. Likely hasn't been used in at least 20 years. Sitting on a curb, and it's 90% working.

Edit 2: I'm an idiot. The vertical hold is on the front. the missing knob on the back, well I'm not sure if theres supposed to be a knob there or not.

I'm going to open it up, apply deoxit to the knobs, let it sit a bit, then I'll try it again.

Getting into this TV, I now believe it's been used recently. The VHF knob is fine, it rotates fine, like new even. However the UHF knob barely turns, and the fine tuning knob also barely turns. Both of those knobs haven't been touched in decades.

Also there's electrical tape wrapped around the twin lead wire that's connected to the VHF tuner. Somebody's kludge repair attempt. The tape looks new and is still sticky.


Edit: Cleaned the pots and switches, took apart the tuner and cleaned it. Fine tuning knob works good now. Sound is perfect. Can't seem to get the horizontal working. Adjusting the knob for it did nothing far as I can tell. The rest of the adjustments seem to work fine now.

Decided to test the camera on this cheap phone. Best video setting is 720p, which doesn't look that great but it's better then 640x480 I guess. Here's the video:
http://youtu.be/hmlqe0YwsPg

I'm not sure I want to put more work into this TV as I have no real use for it. I'd much rather give it to someone whose better acquainted with tube electronics.

Almost new camera barely works. No surprise.
50 yr old TV one easy step from working. No surprise.
Speaks volumes about todays quality.........

73 Zeno:smoke:

Great find !..

Right. I'm going to run it for a few minutes. It's connected to my power strip so if it starts doing anything funny I can cut the power instantly.

Gonna go hook my DTV box to it.

Edit: Well, it works better then I expected a 50 year old TV that I found on a curb to work. Vertical hold knob is either missing or broken.

http://i.imgur.com/VjEoYSp.jpg

http://i.imgur.com/T6bsUkn.jpg


And the camera in this phone is so cheap that green horizontal lines randomly appear in some of the pictures it takes. :thumbsdn:

Knobs need deoxit badly. Sound is fine, except the audio gets randomly scratchy... again, probably due to dirty knobs, and I need to see what's going on with the vertical control. Other then that it works.

So yeah... 50 year old TV. Likely hasn't been used in at least 20 years. Sitting on a curb, and it's 90% working.

Edit 2: I'm an idiot. The vertical hold is on the front. the missing knob on the back, well I'm not sure if theres supposed to be a knob there or not.

I'm going to open it up, apply deoxit to the knobs, let it sit a bit, then I'll try it again.
The CRT looks really bright. Most of those sets needed a CRT, 40 years ago.
A lot of the Motorola sets used National Video CRTs and were rather short lived. That set might have a different sourced tube.
BTW, there was never a knob on the horiz hold shaft. You seldom had to reset them. :scratch2:

I really should stop working on unfamiliar TV's at 1 AM. The horizontal knob I thought didn't work was another knob entirely. Going to give it another try...

Okay. I readjusted the controls, this time paying attention to just what I was adjusting. vertical and horizontal controls work fine, but I can't get horizontal or vertical to lock in place.

Here's a video of it now:
http://youtu.be/2agduuDwDL4

The control on the back that's missing a knob is labeled 'VERTICAL LIN". Not sure what it does or if it's related to why the image won't stabilize. Perhaps there's a weak tube inside the set.

If it's something easy that I can fix, I might give it a go, but again I'm more interested in giving this set to somebody more familiar with tube TV's.

Not the lin control. Go for the sync separator tube 1st.

73 Zeno:smoke:

Swapped around the V7 and V8 tubes and that almost stabilized the image. Now wondering if I have a weak tube or a component that's drifted out of spec.

Swapped around the V7 and V8 tubes and that almost stabilized the image. Now wondering if I have a weak tube or a component that's drifted out of spec.
It's the V11, you're interested in. 6BL8. Next to the IF strip.
Don't use the horizontal osc tube, in case the tube is dead. The horiz output tube could get damaged by lack of drive. :sigh:

Swapped V8 with V11

Picture collapsed to a line and no sound. I think I found the culprit.

So I need a 6BL8 tube. They're pretty common on eBay, but no $ to spend on one right now.

Anybody in the Detroit area want to donate a tube?

The control on the back that's missing a knob is labeled 'VERTICAL LIN". Not sure what it does or if it's related to why the image won't stabilize..

It's a little hard to tell in the picture, but it might be the kind of variable pot that you adjust using an insulated screwdriver. Or maybe the shaft was broken off. If that's the case, and if it's plastic, you might be able to melt into the shaft stub a phlips head screwdriver, to make a philips head you can then adjust with the screwdriver, once it's cooled.
http://videokarma.org/attachment.php?attachmentid=186886&d=1432232778

Almost new camera barely works. No surprise.
50 yr old TV one easy step from working. No surprise.
Speaks volumes about todays quality.........

73 Zeno:smoke:
Haha, exactly.

Funny thing is I just swapped the tubes back and the picture stabilized. I'm still sure that 6BL8 is bad or at least very weak.

they're pretty cheap on eBay. I might buy one unless a VK'er near me happens to have one they;d like to donate.

Funny thing is I just swapped the tubes back and the picture stabilized. I'm still sure that 6BL8 is bad or at least very weak.

they're pretty cheap on eBay. I might buy one unless a VK'er near me happens to have one they;d like to donate.
Or dirty / loose socket or tube pins. Try this. Works real pissah sometimes.
Get a small pair of dikes ( as in wire cutters ! ). Grab the tube pins one
at a time & run the dikes down a few times on each pin. You are
just gently scraping the pins clean. Spray a little cleaner or even WD40
on the socket & put the tube in & out a few times.
There are ways to tighten a socket but with risk.
BTW you can usually tell a bad tube from a socket or pins by GENTLY
pushing on the tube & watching the pix.

I dont know about you but I am having fun working on this old
big M :banana:

73 Zeno:smoke:

I'm having fun myself. It's something, getting the chance to mess around with a 50 year old TV. Much less one that basically works.

Curbside find... half a century old... In good shape, and it didn't blow up when I plugged it in and turned it on, and it only has minor problems. I really want to know how lucky I am here.

The tube sockets feel nice and solid. They don't feel loose. I'll try cleaning the pins on the tubes and spray a bit of contact cleaner in the sockets.

You nailed it Zeno! It's working! Horizontal and vertical lock in perfectly now! TV's playing beautifully!

Check it out:
http://youtu.be/n3hg0GpWqVs

Methinks You're a GOOD Man, Charlie Brown ! Something kinda GRAND & NOBLE about bringing a 50 yr old obsolete, valueless-Practically-veteran back to life... Would that I could do this...But I ain't got Bat Sense when it comes to fixin' this stuff.

Well even if it's worthless, it's still a piece of history and I didn't want it to suffer the fate of being ripped apart by scrappers. Or end up converted into a damn fishtank.

It's entirely possible this TV displayed the moon landings in 1969.
It's possible that it displayed news of the Vietnam war.
The oil crisis of the 70's, the technology boom of the 1980's, the rise of PC's in the 90's. Who knows how long this TV was in operation.

And for it to end its journey at the hands of some scrapper looking to score $2 worth of copper? No. Not if I can help it.

Well even if it's worthless, it's still a piece of history and I didn't want it to suffer the fate of being ripped apart by scrappers. Or end up converted into a damn fishtank.

It's entirely possible this TV displayed the moon landings in 1969.
It's possible that it displayed news of the Vietnam war.
The oil crisis of the 70's, the technology boom of the 1980's, the rise of PC's in the 90's. Who knows how long this TV was in operation.

And for it to end its journey at the hands of some scrapper looking to score $2 worth of copper? No. Not if I can help it.

Perzacly ! We toss the touchstones of our lives too easily in this society...2, 300 yrs from now, I'm thinkin', HOPIN' things like this will be worshipped kinda like Michaelangelos & that sort of stuff is..

Well even if it's worthless, it's still a piece of history and I didn't want it to suffer the fate of being ripped apart by scrappers. Or end up converted into a damn fishtank.

It's entirely possible this TV displayed the moon landings in 1969.
It's possible that it displayed news of the Vietnam war.
The oil crisis of the 70's, the technology boom of the 1980's, the rise of PC's in the 90's. Who knows how long this TV was in operation.

And for it to end its journey at the hands of some scrapper looking to score $2 worth of copper? No. Not if I can help it.
Now you're talkin'.

I wouldn't be surprised if it was Ann Margret's character in Grumpy Old Men who popularized the idea of ruining TVs to make fish tanks.

I decided to make another video... just because I could...

https://youtu.be/rQiWICi4-3k

And the camera on my phone, for some reason records in a 16:10 aspect ratio, yet scales the video to 1280x720 which is 16:9, resulting in a squashed aspect ratio. It also records in a resolution much lower then 720p, so in this video I've corrected these faults as best I can.

Now that the TV works, I should find out its secrets. I'm still hesitant about keeping this TV around, and would *much" rather give it to somebody whose more familiar with tube electronics then I am. However I'm starting to think this is a situation where the thing's adopted me. As far as I know the set's virtually worthless, so selling it isn't happening. Any vintage TV collectors near me likely haven't got the room for a set that's nothing special, and I don't want the scrappers to get it...

So if I'm stuck with this thing, I want to know what I'm dealing with. To that end I plan on replacing the filter cap at the very least. The voltages inside these tube TV's are no joke, and the thought of fifty year old components still handling and regulating these voltages scares me. All I need is for that filter cap or some other high voltage component to go "WELP! I'M DONE!" and cause the set to explode into firey shards and burn my house down...

So, I've grabbed some pics of the chassis. These are the best images that my current camera can take. I'd like to know if there's anything in this TV that should be replaced, and if there are any "OMG replace that now before your set catches fire" components.

Update: I found my old digital camera and got better pictures. Funny how my ten year old digital camera can take better pictures then the camera on a phone I bought a week ago.

http://i.imgur.com/ar5TjBc.jpg
http://i.imgur.com/nGqLGE8.jpg


I've suspected for awhile that the CRT wasn't original, due to the fact that it's not mounted straight. Now I have confirmation:
http://i.imgur.com/uRIFEJy.jpg

It looks like someone cared about this TV enough to replace the CRT in 1978. 2 year warranty. We're well past that now, but the CRT is in great shape regardless.

That chassis is super clean. At most I would change all electrolytics.
As far as going up in flames NEVER give up freedom for safety. The
odds are you will choke to death on a hot dog before this set will kill you.
It may not be worth any money but it comes from a different time &
country when quality & pride ruled. Display it with pride......

73 Zeno:smoke:

I found a power cord that will fit it, so now I can run it with the back off. I got brave enough to do that for a few minutes. I'm pleased to say the filter cap remained nice and cold. I only ran it for about five minutes, but it didn't do anything weird or scary.

I still plan to change the electrolytics. Only problem is I'm not sure how many there are. The filter cap for sure, and that big one that connects to it. What about all those brown things that look like they might be capacitors? And that white thing in the first picture, right below where the power cord plugs in?

Also worth noting is I opened the flyback cage and had a look inside. The flyback looks like it's coated in tar and I saw a few cracks in that tar. Probably nothing serious and I saw nothing flaking off, but thought I should mention it.

Great choice of a video to play on it! Love it!

Thanks. I thought it fitting given that I brought it back to life.

In time I plan on ordering new caps for it. In the meantime if someone spots something else that should be replaced, let me know.

Also, how often should I run this set to make sure nothing in it goes out of whack from sitting too long?

From the moment where you changed all caps , set & tune all the adjustments, you're ready to run your set daily MRX37..

Great work for a guy who says he does not mess with old TVs much :) I got my start on a similar Motorola 2 years older

It was not long after 1965 before the quality of most monochrome sets trailed off, this one is a keeper.

Great work for a guy who says he does not mess with old TVs much :)

I didn't say that. I said I don't mess with tube gear often. I've fixed a lot of solid state TV's and recently touched up the convergence on my Chromacolor II, easily the best set I've owned for displaying ruby reds and emerald greens.

Tube gear is still pretty new and pretty scary to me.

I didn't say that. I said I don't mess with tube gear often. I've fixed a lot of solid state TV's and recently touched up the convergence on my Chromacolor II, easily the best set I've owned for displaying ruby reds and emerald greens.

Tube gear is still pretty new and pretty scary to me.
Tube gear is probably easier to tackle than early solid-state.

By the way, if that Chromacolor II has a white 4-lead safety cap, it has to be replaced with the Zenith 800-860 orange drop, stat.

Oh no worries there! When I got the set from Strawman years ago, the first thing I checked was that cap, and it's nice and orange.

And apart from cleaning the controls and the circuit board plug in contacts, and cleaning goo off the CRT anode cap, the sets never given me any trouble.

I found a power cord that will fit it, so now I can run it with the back off. I got brave enough to do that for a few minutes. I'm pleased to say the filter cap remained nice and cold. I only ran it for about five minutes, but it didn't do anything weird or scary.

I still plan to change the electrolytics. Only problem is I'm not sure how many there are. The filter cap for sure, and that big one that connects to it. What about all those brown things that look like they might be capacitors? And that white thing in the first picture, right below where the power cord plugs in?

Also worth noting is I opened the flyback cage and had a look inside. The flyback looks like it's coated in tar and I saw a few cracks in that tar. Probably nothing serious and I saw nothing flaking off, but thought I should mention it.


Those "brown things ARE capacitors, likely some sort of "film type" A lOT like brown devils or such. They DO go bad after 50 years.

the "white thing" is ALSO a capacitor, an "oil type" likely an "el-menco". they are MUCH more reliable that paper caps or those brown ones...but they CAN fail.

I didn't say that. I said I don't mess with tube gear often. I've fixed a lot of solid state TV's and recently touched up the convergence on my Chromacolor II, easily the best set I've owned for displaying ruby reds and emerald greens.

Tube gear is still pretty new and pretty scary to me.

Transistors scared me initially - they could not take transient overloads without destroying themselves like tubes can. You are right to be cautious with the voltages in tube gear.

Those "brown things ARE capacitors, likely some sort of "film type" A lOT like brown devils or such. They DO go bad after 50 years.

the "white thing" is ALSO a capacitor, an "oil type" likely an "el-menco". they are MUCH more reliable that paper caps or those brown ones...but they CAN fail.

I've seen enough bad elmnco and similar white caps that to me they are as bad as paper caps.

I've seen enough bad elmnco and similar white caps that to me they are as bad as paper caps.

The brown tubular caps are the Good-All brand. Not sure if they're mylar or paper. I know the porcelain tube jobs were paper dielectric.
Look at the boost caps in the Porta-Colors. :thumbsdn:

Oh no worries there! When I got the set from Strawman years ago, the first thing I checked was that cap, and it's nice and orange.

And apart from cleaning the controls and the circuit board plug in contacts, and cleaning goo off the CRT anode cap, the sets never given me any trouble.
I've seen that goo in several Chromacolor sets including mine. I thought it might have been an indicator of high hours, but my Chromacolor CRT tested almost new, so who knows.

Yeah those CCII CRT's were probably the best rectangular tubes Zenith made. They just keep going and going. The later System 3 CRT's just don't hold up as well. Then you got the 90's ones which die after 2 years.

And for displaying color, The CCII could even give the Merril a run for its money.

There are 2 kinds of goo. One the factory put on. Dont
remember which sets but several brands had it. When
the sets got older it turned into a filthy mess that we
cleaned off & didnt replace. Other sets had aftermarket goo.
They came from houses that had a lot of greasy cooking.
Covers everything in the HV. You can tell a lot from
the crap on a chassis. Example a thin white coating is
from a humidifier. A thick white powder is talc & the set
is a bedroom set. Can also tell cat or dog, wood stove,
smoker etc. A nice thing abt SS sets is the chassii
were always cleaner. Some tube jobs had inches of crud that
we took out side to blow out.
And yes 1970's Zenith delta jugs without question were
the best. But in-lines get a bad rap because the delta were so good.
More failures but they came in short runs. Example we saw
many M1970P with bad tubes at 3 yrs but they all came from
one batch of 12 we sold. A call to Zenith got a free tube IF
we agreed to not charge labor. Needless to say we only did
that for "our" sets...
The 90's were different. Those jugs were pure junk.
Zenith did extend them up to 5 yrs. The higher end the set
was the longer they extended it.

73 Zeno:smoke:

73 Zeno

Ah the joys of demonstrating 50 year old electronics. Got a new problem.

Know how when the TV image first comes up, it's large and dim, but then shrinks to proper size and brightens? Now it's not shrinking or brightening, and adjusting the brightness control makes the image go dark at both ends of the knob's range.

So the TV has a large, zoomed in image. It has been sitting I haven't messed with anything on it. What could have happened to it?

Bad HV rectifier tube is one possibility, particularly if the picture looks okay otherwise.

Turning the brightness up puts an extra load on the tube, if it's weak it can't supply enough HV and the picture blooms and darkens.

Yeah the picture looks fine otherwise, maybe slightly distorted?

Could it perhaps be a loose socket? Do rectifier tubes just decide "WELP! I'M DONE!" and fail immediately?

No, HV rect tubes can lose emission, resulting in voltage sag under load and 'blooming'. It's a not-uncommon problem.

Wouldn't that be a slow process though? This just happened instantly after a few months of sitting unused.

EDIT: decided to reseat the Hv rectifier tube and what I assume is the shunt regulator tube, and now there's no HV. Perhaps i should take a look at those sockets.

Black and White TVs DO NOT contain HV regulator tubes or HV regulation.

Wouldn't that be a slow process though? This just happened instantly after a few months of sitting unused.

EDIT: decided to reseat the Hv rectifier tube and what I assume is the shunt regulator tube, and now there's no HV. Perhaps i should take a look at those sockets.
Did you check the B+. The brown voltage doubling cap under the chassis, might be going bad. The B+ should around 265-270 volts DC.
The set uses a 3AT2, HV rect, 6AL3 damper and a 6JN6 or 6HE5, horiz sweep output.
Hopefully, the flyback didn't pick up moisture and short the winding. Motorola flybacks were probably one of the most reliable, but could fail after 50 years. :scratch2:

I have a hunch.

The tube I reseated was not the HV rectifier tube. I learned from working on the Sylvania that the HV rectifier is hidden inside the flyback cage, and sure enough I found it inside the Motorola's flyback cage as well. I pulled it out and one of the pins was coated in goop. So I cleaned it and the socket with contact cleaner and put it back in. Now just waiting for the residual to dry. It's supposed to be non conductive but I always give it an hour to dry to be safe. I'll update this post with the result soon.

EDIT: Aaaand... nothing. So where's this voltage doubling cap and how do I measure B+ off it?

I have a hunch.

The tube I reseated was not the HV rectifier tube. I learned from working on the Sylvania that the HV rectifier is hidden inside the flyback cage, and sure enough I found it inside the Motorola's flyback cage as well. I pulled it out and one of the pins was coated in goop. So I cleaned it and the socket with contact cleaner and put it back in. Now just waiting for the residual to dry. It's supposed to be non conductive but I always give it an hour to dry to be safe. I'll update this post with the result soon.

EDIT: Aaaand... nothing. So where's this voltage doubling cap and how do I measure B+ off it?

You don't measure the B+ from the voltage doubler cap, you'd measure it from the first terminal of the large electrolytic cap.
If you look at the tube location diagram, you'll see the terminal points, where the focus taps are. It shows, B+, grnd and boot. Motorola always referred to boost as boot or bootstrap voltage. Be careful, measuring the boost, as I might be 1KV or higher. I wrecked a few meters checking boost voltage. Right now, all you're interested in is the B+ voltage.

Lets try and simplify this, well, for me anyway. I'm still very new to tube electronics, and I'm learning as I go. Please bear with me.

Now that I have a decent camera again, here's a full, high resolution shot of the chassis:
http://imgur.com/JFDq0nP

If you'd be kind enough to point out where I need to put my meter leads, and maybe some other areas where I should test voltages, that'll cut down on the number of stupid questions on my end.

See if you can show the TOP of the chassis for me....it will help me to figure it out better.

So far...I THINK...I see where you need to check. Looks like the main filter cap is on the extreme right....partially under the bottom of the cabinet. I only see a BIT of it...and need to see the TOP of the chassis, to tell if there are MORE caps...that need to be checked.

Scratch that....I checked an earlier post...and now see the chassis.

Better top chassis shot, if it helps:
http://i.imgur.com/zm3r8Pd.jpg

Looking at the chassis tube layout...I see where you need to check for B+. You can either reach it on TOP of the chassis or UNDER It.

Next to the H-put tube...is a terminal strip. The THIRD terminal post is B+. CHeck this to GROUND...and see what it reads. you can ALSO measure this under the chassis, the third termnal is under that black capacitor.

I see what look like a diode under the chassis. It is under that red cap...above the brown tubualr cap--which is likely one of the doubler caps....ASSUMING...this set uses a doubler. The other doubler cap is likely part of the can cap on the right of the chassis.


IF this is a doubler power supply...you should have at least 275-285 volts B+ If NOT a doubler....only 140-150 volts.

And as others have said....do NOT measure the "Boot' or Boost voltage...UNLESS you have a meter than can read 1KV or so....it could eb that high. Measure ONLY the b+ right now..I suspect it is LOW....from your symptoms..

B+ voltage starts off at 310 volts, then drops to ~265 on warm up. Seems like it's in range according to DieselJeep's post.

That sounds fine. NOW...you need to see if HV is up to snuff... For that you will need a HV probe.... a set like this should be producing at least 15-20KV... NO lower than 15KV..

That's where I hit a wall... HV probes aren't cheap, and I'm flat broke.

That's where I hit a wall... HV probes aren't cheap, and I'm flat broke.

Hit up a repair shop or ebay for a cheap used one.

Well for now lets assume there's little to no HV. I think the image blooming out before it totally failed is enough evidence to suggest that

Lets also assume that the HV rectifier tube is okay, seeing as those should gradually fail and the last time I ran the set, the image was clear and bright.

And lets assume...hope to god... that the flyback didn't decide to up and quit on me.

What else could be causing this lack of picture issue?

The HV rect. could be the problem......It could be that the previous issues were a weak HV rect, and the filament opened since then killing the tube. A good way to tell in absence of a tube tester is to ground the blade of a flat edge screw driver, with the set off lift the top cap on the rect enough that some of the metal is exposed, turn the set on and try to draw an arc/corona off the HV rect top cap. If all is well with the fly etc. you should be able to draw a 1.5" or longer arc from the HV rect. top cap. On some of the rubber tire fly roundys one can draw 1/2" of spark off the fly tire.

Not enough room in that flyback cage to get a blade under that top cap. Also I wouldn't trust myself to attempt this as I'd probably jump at the arc and the screwdriver might go somewhere it shouldn't.

I think it's worth locating a replacement tube to try, because I'm getting the feeling if it's not that, then it's probably the flyback... in which case might as well junk the set.

Could I visually inspect the rectifier tube and see if I can spot an open filament?

if the filament is intact, you will see continuity across those 2 pins on the tube. What tube does the set use?

A continuity check at the heater pins of the unplugged tube should tell you a good bit about it's health, now that I think about it.

It is easy for a set with a good fly not to produce HV.....It could be caused by a large number of things such as the H osc. not working to spec., the H output tube being weak or miss-biased(any element too far off could kill HV and or cause redplating), horizontal stage fuse being blown, yoke bad or unplugged, HV rect tube bad, or it's heater winding shorted to ground, bad damper tube, etc., etc, etc.....

Don't give up. Get a schematic for it if you don't have one, and check measurable listed voltages in the horizontal section of that schematic and look for discrepancies.

You should put a tube tester on your list of equipment to get. They won't find all problems in horizontal stage tubes, but they will keep you from putting tubes in your set that are DEFINITELY not going to work, and you can never be sure a NOS tube is good without testing it.

...A good way to tell in absence of a tube tester is to

GROUND THE BLADE

of a flat edge screw driver, with the set off lift the top cap on the rect enough that some of the metal is exposed, turn the set on and try to draw an arc/corona off the HV rect top cap.
O jeezus. Not this old chestnut again.:eek: Yikes. There is no need to ground anything. If the fly is working OK, the screwdriver will draw a healthy 'air arc' a half-inch or so long. (Of course the screwdriver needs to have a well insulated handle to hold it by.)

Striking a direct-to-ground arc off the HV secondary is compounded by the fact that the winding is forced to carry B+ current plus the excessively high RF component. Please don't tell noobies to do this.

The HV rectifier tube is a 3AT2. let me know what pins to test and I'll pull it and see if there's continuity

heater is pins 12 and 1, each side of the heater is connected to multiple pins
http://www.mif.pg.gda.pl/homepages/frank/sheets/123/3/3AT2B.pdf

Okay, looking at various tube diagrams, it seems that holding the tube so the gap is at the 6 o'clock position, pin 1 is always on the left. So going by that logic I connected leads to pins 2 and 12, and get about 2 ohms. (Just saw the updated post, and did pins 12 and 1 too, same reading)

I think the tube is good.

Now, Electronic M mentioned that the horizontal output tube could also cause HV loss, as can a bad damper tube. Before I totally lost picture, I did remove and reseat the horizontal output tube (I mistook it for the rectifier tube) and the damper tube (mistook it for a shunt regulator... yeah I know...)

Can i do a continuity test on these tubes as well?

yes, but that doesnt tell you much, if the tubes light up, the heaters are obviously good.
more informative would be measuring the voltages on the tubes, to see if they are in the ballpark. Trouble with those stages should show up in weird readings. Folks on here should be able to interpret the results and tell you what to test next. A good filament also does not mean a tube is good overall. Just that the filament is OK. all the stages in the horizontal section, HO output tube, H. Oscillator, Damper, and HV rectifier all work together to generate HV, and all stages need to be within spec. One leaky cap or shorted flyback winding can kill the picture, or let out smoke...

UPDATE:
http://i.imgur.com/7Hvsygs.jpg

This is why I didn't have a picture! Must have knocked it off when I reseated the Horizontal tube!

Picture's back, but it's still bloomed out. Horizontal tube is obviously good. Where do I go from here?

Edit: decided to test B+ again now that the yoke was connected properly, and it actually went up slightly. It's now in the 265-267 range which is where it's supposed to be.

I guess unless you guys can think of something else, I'll see about procuring another 3AT2

UPDATE:
http://i.imgur.com/7Hvsygs.jpg

This is why I didn't have a picture! Must have knocked it off when I reseated the Horizontal tube!

Picture's back, but it's still bloomed out. Horizontal tube is obviously good. Where do I go from here?

Edit: decided to test B+ again now that the yoke was connected properly, and it actually went up slightly. It's now in the 265-267 range which is where it's supposed to be.

I guess unless you guys can think of something else, I'll see about procuring another 3AT2

I have several 3AT2 tubes in my tube caddy but the only problem is that I don't know where you live and I don't exactly trust the postal service with my mail (especially not my mail carrier).

I have several 3AT2 tubes in my tube caddy but the only problem is that I don't know where you live and I don't exactly trust the postal service with my mail (especially not my mail carrier).

Your state borders mine. (I'm in Michigan)

if packed well, tubes travel just fine via post office. I received a 12HLT today from California and it made it fine.

Your state borders mine. (I'm in Michigan)

if packed well, tubes travel just fine via post office. I received a 12HLT today from California and it made it fine.

Whereabouts in Michigan? we could meet halfway and I could just give you the tube for a little gas money.

Like I said I have quite a few of those 3AT2 tubes in my tube caddy and probably will never use them and as far as I know they're NOS tubes.

UPDATE:
http://i.imgur.com/7Hvsygs.jpg

This is why I didn't have a picture! Must have knocked it off when I reseated the Horizontal tube!

Picture's back, but it's still bloomed out. Horizontal tube is obviously good. Where do I go from here?

Edit: decided to test B+ again now that the yoke was connected properly, and it actually went up slightly. It's now in the 265-267 range which is where it's supposed to be.

I guess unless you guys can think of something else, I'll see about procuring another 3AT2
When you see the blooming out image, does it look like an irregular shape?
If it's an irregular shape, it might a yoke problem. As a result, the set will not produce sufficient high voltage. :sigh:

I think the no signal box looked very slightly distorted. Attached is a picture of it. It's about twice as big as it should be.

Also noticed that when turning the brightness knob up, the image blooms out even more and shrinks when i lower it. Definitely low HV. question is... is it a bad rectifier tube, a bad damper tube, a bad flyback or a bad yoke?

Or something else?

I think the no signal box looked very slightly distorted. Attached is a picture of it. It's about twice as big as it should be.

Also noticed that when turning the brightness knob up, the image blooms out even more and shrinks when i lower it. Definitely low HV. question is... is it a bad rectifier tube, a bad damper tube, a bad flyback or a bad yoke?

Or something else?
At this time, I would first try a new 3AT2.

Yeah they're cheap enough on ebay. When I get a few bucks together I'll order one.

I think the no signal box looked very slightly distorted. Attached is a picture of it. It's about twice as big as it should be.

Also noticed that when turning the brightness knob up, the image blooms out even more and shrinks when i lower it. Definitely low HV. question is... is it a bad rectifier tube, a bad damper tube, a bad flyback or a bad yoke?

Or something else?

You have full width so 95%+ chance its the 3AT2. I learned
many years ago NEVER say 100%.
You can 99% eliminate yoke, FBT.
Tiny chance its the damper or hoz out. H out are almost
always VERY expensive.

73 Zeno:smoke:

Oldcoot 100% on this. DO NOT draw arcs to ground.

The ONLY time to use ground is to discharge the CRT with the set
UNPLUGGED ! And not at the plate cap. That wont work.
Go under the anode button.

73 Zeno:smoke:



O jeezus. Not this old chestnut again.:eek: Yikes. There is no need to ground anything. If the fly is working OK, the screwdriver will draw a healthy 'air arc' a half-inch or so long. (Of course the screwdriver needs to have a well insulated handle to hold it by.)

Striking a direct-to-ground arc off the HV secondary is compounded by the fact that the winding is forced to carry B+ current plus the excessively high RF component. Please don't tell noobies to do this.

Well I might be getting a generous donation of a 3AT2, and a tube tester, the latter of which would be a big help to me.

In any case, a new 3AT2 is the next step.

Thanks to a generous donation from Captainclock, I received a new 3AT2 tube, AND a tube tester! :banana:

Put in the new tube, and it seems to have solved the problem! I'll need to do a longer test later when I have time but the raster came up bright! :yippy:

And it looks like the tube tester survived shipping with no issues. I tried the new 3AT2 (after looking up the proper settings in the manual) and it read full emission, and the old one got up to the ? between good and bad... So I think it was marginal and finally quit.

Well, now that I have a tube tester, there's really only one thing to do:

http://blog.centresource.com/wp-content/uploads/2014/09/TestAllTheThings.jpg

Looks like most of the tubes in that Motorola are in excellent shape! I do have a 6BL8 that came up on the lower end of the good range, but it's still good.

Decided to make a quick thank you video:
http://www.youtube.com/watch?v=Z1Y6t9Vqi1g&feature=youtu.be

And thank you all for the assistance!

That chassis is super clean. At most I would change all electrolytics.
As far as going up in flames NEVER give up freedom for safety. The
odds are you will choke to death on a hot dog before this set will kill you.
It may not be worth any money but it comes from a different time &
country when quality & pride ruled. Display it with pride......

73 Zeno:smoke:

Very well said...... Maybe even quote of the year.........

.

Looks like most of the tubes in that Motorola are in excellent shape! I do have a 6BL8 that came up on the lower end of the good range, but it's still good.

Decided to make a quick thank you video:
http://www.youtube.com/watch?v=Z1Y6t9Vqi1g&feature=youtu.be

And thank you all for the assistance!

Those TVs looked very nice in the video, kind of makes me wish even more that I could get mine going, but I think mine is going to be really tricky to getgoing again, especially since I found out that my HV wire terminal going to the picture tube plug is broken and have I no idea how I'm going to fix that sucker. :sigh:

You mean the connector that's under the rubber cup and the wire for it?

Heck, you could probably get something suitable from a junked 13" or smaller portable TV. I doubt the year or model would matter as long as it was the right size.

if all else failed you could probably craft one from a little piece of sheet metal and solder it to the wire.

You mean the connector that's under the rubber cup and the wire for it?

Heck, you could probably get something suitable from a junked 13" or smaller portable TV. I doubt the year or model would matter as long as it was the right size.

if all else failed you could probably craft one from a little piece of sheet metal and solder it to the wire.

nope, something like an actual pinout on the actual tube socket itself, this TVs picture tube doesn't use an anode cap, the high voltage anode is built into the tube socket itself, like shown in the pictures below.

Heck that looks like it can be fixed with a bit of solder, and maybe a dab of epoxy for good measure.

Heck that looks like it can be fixed with a bit of solder, and maybe a dab of epoxy for good measure.

I thought about that but I don't have any way to hold the two pieces together for a clean solder job and I also don't have any epoxy left either...:sigh:

Try one of these beauties:
http://www.ebay.com/itm/Helping-Hand-Soldering-Stand-With-LED-Light-Glas-Clip-Magnifier-Magnifying-Glass-/131483056320?hash=item1e9d0038c0:g:oHIAAOSwqu9VJ5S r

And epoxy's cheap.

Try one of these beauties:
http://www.ebay.com/itm/Helping-Hand-Soldering-Stand-With-LED-Light-Glas-Clip-Magnifier-Magnifying-Glass-/131483056320?hash=item1e9d0038c0:g:oHIAAOSwqu9VJ5S r

And epoxy's cheap.

I would like to get one of those but that's kind of out of my price range for the time being... :sigh: