According to Sams there should be solid continuity (zero ohms) from pin 3 of the flyback to the Height control. Since there's only 250V at the Ht control, find out where the open is. That .1 cap is not a problem if you already replaced it.

Also see if there's Boost at the screen controls. As jr_tech mentioned, if it's low it will knock the brightness down.

WAG.... the wire/run between the HV cage and circuit board that carries the 670v boost voltage to the screen and height pots is broken or cold soldered... the 250 volts measured on the height pot is actually from the 270 volt supply back feeding through the screen pots. :scratch2:

jr

So... if indeed there's no Boost at the scr. controls, turn all 3 down to minimum before the Boost is restored to them. Otherwise, the CRT will be overdriven and may bloom out, an unfamiliar situation for a noob.

Okay, precautions were taken as suggested. Screen controls were minimized before I started poking around again.

Sure enough, no boost voltage at any of them. In fact, the entire boost line on the PCB was dead.

So I checked the wire. Wire was good, but there was no continuity to the board.

It turns out that the same solder joint for the wire linking to pin 3 on T4 is also used for the connection to the .1uf boost capacitor, which I replaced. Apparently when I did that, the solder didn't flow properly around the boost supply wire and left it essentially hanging in midair. It was hard to spot, but when I was actually looking for problems at that joint, it was obvious that the solder had pooled around it and wasn't actually connecting.

Moreover, I've identified the source of that HV sparking, and it wasn't the flyback. As soon as I pulled the board out, I saw sparks shooting from that solder joint. Apparently they were jumping between the gap and periodically supplying boost voltage, which explains why the picture kept filling out.

So anyway, I resoldered that joint. And sure enough, I have full deflection again!

Now I can focus on a few other issues. The color sounds like it won't be hard to tackle, and I'll plan to focus on that next since I have the board loosened and accessible.

I'm also still concerned about the brightness. It seems like the picture goes completely dark for a significant portion of the control. Not as much now that boost has been restored, but still more than I'd like. Maybe that's the nature of these sets? Or does that sound like a tired CRT? I don't have a tester with me, but should I start keeping an eye out for a replacement?

Now that boost is restored, an old issue has come back. I'm noticing those flashes of bright light again, and they aren't impacted by the brightness.

I've taken a video of the progress at this point. I'd like to fix the color next, but I also made sure to capture the flashes so you can see what I'm talking about. Any thoughts on what that might could be?

Here's the video: https://youtu.be/LEAJsa0N-FU

That type of flashing was usually caused by a defective video output tube. Will not show up in a checker, only way to tell for sure will be to sub the tube.

Tap the tubes gingerly with something like a screwdriver handle. It'll usually show up any intermittencies. Tap around on the board too. The 'tap test' was an integral part of troubleshooting back in the day.

Temporarily disconnect anything from the ant. input just to be sure that flashing isn't 'hitchhiking' in from outside the set.

That 'flak' looks a lot like the RF noise from a motor running picked up by the TVs RF system.

Okay, brief update. I'm pretty sure the video output tube is causing it.

I was able to get the lines to start and stop by tapping the 11BT11. I've gone ahead and ordered a NOS one, so I'll see if that fixes it. I've also been noticing that the sound and video keep dipping and then coming back, almost like the signal is being muffled. Tapping that tube seemed to correct that as well.

As far as motor interference being picked up, this happens regardless of the location in the house, and there aren't any nearby motors. So I think it's internal to the set.

Since another section of the 11BT11 also contains the sound/sync amp, that could also be affecting the sound as you mentioned.

Incidently, see if the contrast control varies the intensity of those flashes (it's located on the furthest-to-the-right end of the back apron).

“I'm also still concerned about the brightness. It seems like the picture goes completely dark for a significant portion of the control. Not as much now that boost has been restored, but still more than I'd like”

Where are the screen controls set?

jr

There doesn't appear to be any kine bias or brightness range adjustment. If it turns out more brt range is needed, there's a little bit of "engineering fudgery" that may improve it. Just jump a resistor from brt. control wiper to ground. I'd start with 2 meg to be conservative. Then work downward in R value till desired range is reached.

What it does is make the CRT cathodes more negative, hence the G1s more positive with respect to the cathodes.

Again a decade box would be handy

So jumping all the way back to this. I went ahead and tested the resistor in question. It's hitting around 140V on each side. I'm not seeing any significant drop in between. I'm gonna recheck that. It's buried very deeply in and difficult to reach with the probe. But assuming that's correct, does that sound correct to you all, or does that seem unusual that there's no significant voltage drop across the resistor, even if there is continuity?

As for the .01 cap, how would I go about measuring that?

I suppose I could also sub a tube to be safe as well. I reverified that there's no voltage on pin 9, so somewhere between that resistor and pin 9, I'm losing voltage. Maybe a cold solder joint? I haven't done any soldering there as of yet, but I've heard solder joint issues are a common problem in portacolors.

On the foil side of the board, look for a crystalized joint where that resistor's lead comes thru the foil, or where pin 9 comes thru the foil. If there is, re-flow the joints or tack a wire between the two joints.

I'm still waiting on that video output tube to come in, but I wanted to check in about something I'm noticing.

When I turn the brightness down, the picture grows much larger and the vertical seems to bob up and down. It doesn't lose sync, but it's significantly impacted for a moment.

Is that normal? Is that a sign of an issue?

Also, a quick update on the color problem.

Since my vertical is finally back, I decided to go ahead and plug in a video source to get the geometry locked again. In doing so, I noticed that I was no longer seeing that color line.

I wasn't happy with how cramped measuring on the top was, so I decided to do a few voltage tests from the bottom. I had to remove an RF shield to get there, but I was able to uncover the pins for the 8BU11. Reverified pins 3 and 10, those are still a little above 200V, but now pin 9 is reading just above 130V. So it looks like whatever wasn't working is now working again.

My current theory is that the tube pin itself was dirty. I never did clean those, probably should but I always get so excited to dig into the obviously bad capacitors that I skip that step. I've removed that tube a few times and I'll bet in the process of removing and installing it, I eventually cleared the block. I'll keep an eye out to see if it comes up again but I'm cautiously optimistic.

So right now my only remaining issues are the bad video output tube, which is on its way, and possibly that brightness issue I pointed out. Once I fix those, I can clean up the cabinet a bit, do some geometry and color adjustments, and this thing should be good to go (hopefully).

So... is the set now producing a color picture, with proper tint control range?

I think so. I at least know all the voltages to the tube match.

I may need to call in someone to verify for me on whether it's "proper" though, since I'm color blind.

How do I tell if the range is proper? Would a video help here?

A brief vid would help, showing what the color and tint controls are doing when rotated thru their full range, preferably including a pic containing flesh tone (since flesh tone is center reference for tint range). That brightness problem would be interesting to see also.

Okay, here's a showcase of where I am. Sorry for the long video, I was trying to capture everything that came to mind.

Highlights are:

The new video output tube seems to have cured the issues with those bright lines and the signal loss.

I'm noticing some odd behaviors on channel 8 and 9. 9 got better over time, but the static seems dramatically different on 8 from how it appears on the other channels. I showcase that in the video, but that may be normal.

There's a lot of noise in the picture even when I have a stable input signal. It appears to be a sort of cycling movement, scrolling up, and then scrolling to the side. I'll check a few more signal sources to see if that changes depending on the source, but someone else may recognize that issue.

As I already stated, the vertical wobbles when I lower the brightness, and the picture changes size.

There's audio buzz that I'm noticing, but that may also be a signal thing. It's not AC hum.

The color is off. I know the screen needs to be adjusted, but I'm noticing that the colors also seem to be out of alignment and following the cycling movements I mentioned before. I'm not sure if that's an alignment thing or a sign of a problem.

This isn't showcasing flesh tones yet. I'll need to grab a DVD player and set that up. I'll plan to tackle that this weekend. Right now I'm just focusing on picture stability and RF noise. I guess at this point I'm calling the picture "stable" but I feel like it could be better.

Video: https://youtu.be/XHZcKReAZ6A

I left comments under your video, copied here:

Dark band on channel 2 with no signal - this is probably a slight oscillation coming from the power supply - nothing to worry about, should disappear when you have a normal signal.

Snowy picture with a signal - needs to be diagnosed and fixed. Could be anywhere from a broken antenna wire, or something in the tuner; not likely to be the IF though there is a tiny possibility.

Range of the brightness control with picture completely black may be normal due to sloppy design.

Change of picture size with brightness or fine tuning bringing up stronger image - probably normal. Just make the vertical size a bit bigger to hide the black edges.

Vertical collapse when changing channel - big noise in the signal momentarily kills the vertical - needs to be diagnosed and fixed.

Where you point to color at the bottom, all I see is reflections from the table.

Not sure what the squirmy noise is from, probalby some other nearby equipment? You may have a bad signal connection, as I said above.

The color interference you point at (which I can't see very well) could be an interfering signal of some kind just like the squirmy noise - need to get a good strong noise-free RF connection before going further.

The coarser, stronger interference on channel 8 with no signal is unknown, but again, no use trying to chase something that likely occurs only in a no-signal condition, until you can show that it occurs with a good signal.

In summary, on channels with no signal, you should expect to see snow and hear white noise. You do see snow, so don't worry about it until the strong signal problems are fixed. However, if you don't hear audio white noise, there is something wrong with the sound section.

Thanks for the suggestions. So I take it as far as the blurry picture goes, I should start by looking at my signal going from the antenna inputs to the tuner? I know the internal wiring from the inputs to the tuner is right where I was doing a lot of soldering for the filter caps. I wonder if it got damaged. I try some alligator clips across it and see if anything changes, perhaps?

Any thoughts where the "big noise in the signal" might be coming from? Could that be a tuner tube developing an issue? Or maybe a dirty tuner?

I am hearing static audio on the channels with no signal, by the way. I just had it turned down during recording. Beyond the filter hum when I started, I haven't had any audio issues with this.

The problem is most likely in the antenna leads, but I suppose the signal from your source could be weak - do you have another good TV to try it on as a quick sanity check?

The "big noise" is normal switching transient when you change channels. Even though the sync separator circuit may see it as a momentary erratic sync signal, it should not cause the vertical to collapse. This would lead me to check components between the sync separator and vertical sweep section, as well as components in the vertical section itself.

Thumbs up on the audio noise!

Yeah, right next to the workbench actually. I'll do that the next time I'm down there.

That's the 8BU11 again. That's been giving me some strange behavior. I've got a spare coming, I wonder if the tube itself is acting up. I say that because the vertical collapse is a new issue, and that tube only recently started giving me trouble.

When you get your DVD player hooked up and ready to display actual color pics, first you need to set the B&W tracking or 'grey scale'. With the color control full Off, and brightness set very low, adjust the Screens so all three extinguish at exactly the same point.

Okay, here's a big update post.

Of the problems I listed last time, several are now fixed.

I replaced the 8BU11 tube, which has the sync separator. Sure enough, the vertical is no longer collapsing when I change signals. Picture is much more stable.

I also figured out why there was so much interference in the video. My matching transformer had a broken lead. I swapped a new one and the picture has cleared up.

I had forgotten my DTV converter box can play video from USB, so I went ahead and added a clip to check the colors. I haven't done a full greyscale alignment or anything, but I was able to prove that the color and hue controls work, and get the display pretty close to what I'm looking for. So I'd say my color is working fine now, minus the adjustments I need to make.

There's a few outstanding issues. I've taken a video to show them: https://youtu.be/5xGn8A43S5A

There's a lot of buzz in the audio. I can get it to come through clear enough to understand it, but even with fine tuning the buzz never goes away fully. Is there an adjustment I can try somewhere? Maybe in the audio IF?

I'm also noticing a slight ghosting issue, especially when the images are static. It's almost like there's a second image slightly to the side of the color one. I've read about a delay line issue causing that, but I'm not sure how severe that would look. Alternatively, could it be a convergence problem? I tried to showcase that in the video.

Also, what I didn't show on the video, and I can go back and try to find this, is that when my signal isn't tuned in quite right, I often end up with a good image that's only in black and white. I can reliably get the color image adjusting the tuning. This isn't something that happens regularly, it only happens if the signal isn't tuned in properly. Once I lock it in, it's rock solid. I don't know if that's normal or not, but I figured I'd check.

Greyscale adjustment is done. It wasn't far off, but it looks even better now.

I touched up the geometry too. Vertical is much more stable as I adjust brightness. I may do another round later.

I noticed it was a little stretched to the left, though. Does anyone know how to adjust the width?

First off keep in mind what a Portacolor is & isnt. It was built to
sell at $220, later $199. As a rule everything was the cheapest
possible with the lowest parts count. Brand new they "worked"
and thats it. Do not expect perfection from it, GE didnt.
GE stands for "Good Enough" dont you know.....

One thing we found was a PC, especially a first gen like yours after
a few yrs needed a lot of work If we changed one low level tube at a
time you could see improvements with each one. Bad news is
compactrons cost $$ even in 1970. So they were fixed to "work"
again & no more.

Notes
Audio. Put it last. Buzz is detector stage, hiss is audio IF stage.
Vert collapse not normal.
"Blooming" change in pix size probably normal for this set. It is not
highly regulated like in expensive sets.
Tuners have 3 bands. VHF low ( ch 2-6) VHF high ( ch 7-13) &
UHF ( ch 14-83). When the UHF is used 3 things happen.
1) UHF tuner gets power. 2)The VHF osc gets turned off.
3) The RF amp & the mixer in the VHF tuner are turned into two more
stages of IF amps.
So you can get very different performance on different bands with weak tubes. But it can give you clues.
BTW they will usually test good.

IMHO your best next step is to get a good stable source of a color pix
pref a DVD with an RF out.

enuf fer now
73 Zeno:smoke:
LFOD !

I say "width" but on second thought I think horizontal linearity would be what I'm looking for.

Though to be fair, I wouldn't be shocked if there wasn't a way to adjust that. This may be one of those "good enough" things.

0) Glad you found the broken wire

1) Losing color with fine tuning wrong is normal. Nothing to fix except adjust the fine tuning.

2) Things you point at in still pictures are hard to see in a video due to the coding artifacts on YouTube. Post some still pics here and we will be able to see what you mean much better.

3) Nothing wrong with using the USB player for test material. I have one (I think the same model) and it works fine for me

Regarding the buzz, there are two sound coils, the !F and the detector ('quadrature') coil. They're both located right close to the 12BF11. The detector is the one you want to try tweaking first. it's the one located more 'inboard', while the IF is the one out near the corner of the board.

But get the best color picture tuned in first. Then peak the detector for least buzz, and then adjust the IF a bit for best sound. Sometimes you gotta juggle the two a bit.

Sometimes you can minimize buzz with the AGC adjustment too.

As far as picture goes, I'm happy with it at this point. It looks like most of that ghosting went away when I adjusted the greyscale, and I'm thinking that most of that is just the nature of the set. This still has one of those early tubes with much lower resolution.

I'll try adjusting the audio, and if that works I think I'm about ready to declare this set finished, minus a few cabinet cleanups.

Played with both coils. Wasn't able to get things much better.

Would it be worth trying a new audio tube? How reliable is the audio diode?

I tried to grab a few more pictures of that bleed/shadow image. Hopefully these show up. It's kind of hard to see. There's a dark shadow to the right of each image.

Still playing with the audio buzz, but no luck. I can't get it much better than it already was. I've ordered a new audio detector and output tube to check whether that's causing it, but maybe there's another coil I could adjust? It definitely seems like it's impacted by the video.

The buzz may be from your source. Remember when this was built
there were no add ons like VCR, DVD, games, cable boxes & most
old sets dont like them. AGC & fine tune can affect them also.
The DVD with RF out is the best choice but even at that lettering will drive you nuts with buzz & streaking.

Fine tuning acts like this, I will go clockwise the way most do.
First you get a poor B&W pix & weak sound. As you go CW the
pix & sound get better. A little farther & the color pops in.
If you keep going you start getting a wormy pix then it will go away.
If you keep going you will you usually hit the next channel up.
If a set has AFT, AFC or auto color buttons turn them OFF
before FTing. You dont have them, it "works" without them.

73 Zeno:smoke:
LFOD !

I suppose that's possible. Maybe I can swap in another input source and see if the buzzing changes. It still feels like I should be able to get it better than it is, though.

The buzz could possibly be the 'nature of the beast', owing to the highly unusual sound take-off scheme. Both sound and sync are combined in a single triode section of the 11BT11. The actual takeoff point is the plate of the 3rd IF stage, rather than right after the video detector as in conventional designs. It looks like GE's way of going el cheapo and still make it 'work'. It may indeed have worked passably in the days before digital players, digital converter boxes etc.

You might still try subbing the 11BT11 just for the heck of it.

I just swapped in a new 11BT11.

I've heard some tubes have manufacturing variances, though. Maybe I'll swap the old one back in and see if the audio changes? The old one had video issues but I could at least figure out if there's a problem with the new one.

Okay, so, no luck with the 11BT11. Although swapping back and forth allowed me to double verify that the video lines and flickering were coming from that.

However. My environment has changed since I started on this. Over the weekend I finally got my home tv transmitter started. I've only got two channels up at the moment, but I decided to see what happened using that. Sure enough, it improved the audio home dramatically. So I'm going to call this done for the most part. Here's the set working where I plan to use it. https://youtu.be/s2wph0EkvUg

There's a few odds and ends I'd like to wrap. There's a slat broken off on one of the vents in the back. I'm planning to have a replacement 3D printed. Unless someone has a spare. I'll attach a picture.

I'm also having a few issues with my transmitter. Namely, I'm noticing that any television I have hooked up where my portacolor is (this is only happening in one location at home) experiences vertical loss and bouncing periodically. Nowhere else in the house is that happening, and it's only happening on over the air transmissions.

I may start a new thread for that, but does anyone have any experience with that happening?

“ I'm noticing that any television I have hooked up where my portacolor is (this is only happening in one location at home) experiences vertical loss and bouncing periodically. Nowhere else in the house is that happening, and it's only happening on over the air transmissions. “

Sounds like the portapottie is generating a bit if rf interference that is bothering the other tvs... likely in an area of the house with the weakest signal from the modulator. :scratch2:
Might try a snap on ferrite filter on its line cord, it might be helpful to bypass its power supply diodes with high quality caps, 10 nanofarad or so.

jr

First off that set is running very good, about how I remember
one back in the 70's. Well done !

The vert collapse issue is bizarre. Both the vert & horz osc should
be free running at about the right freq without a signal. Only thing
I can imagine is the vert sync pulses from your source arnt right
& the vert is trying to lock way off freq. I do remember a few sets
that "blinked". It was always a bad cap in the vert feedback
( parts running from vert out plate to vert osc grid).

Now that this is wrapped up hows about finding another set for us
to work on :thmbsp:

73 Zeno:smoke:
LFOD !