Tom, my spray can of contact cleaner only had about a drop left in it, so I ended up using WD-40 for the time being. I will order some Deoxit. That did seem to make the controls somewhat less sensitive. I can now get a pretty stable pic, but the horiz keeps pulling.

Bill, this set does not use a video det diode. It uses a 6AL5 tube which also is the DC restorer. I tried another 6AL5, but that didn't help. Sometimes the pic is better than others. As far as the voltages on the 6AL5, my Riders says pin 1 SB 32V, and I have about that. Pin 2, however SB -3V and I have about +9.6V.

Doug

See it the Ryders spedifies the condtions under which the voltages were meassured. Things like with no signal or with signal. And possibly with the controls set a particular way.

If the sync seperator is producing marginal sync, that often cuases more probllems for the horizontal than for the vertical. If the video going into the sync seperator is marginal then the sync comming out will usually be marginal too.

All Riders & Sams says is Vol set at min, Focus at Max. Neither day anything about if a signal is applied or not. I think I found the issue in the washed out pic. I had checked the CRT once before and it was ok. This morning I put it on the checker and let it "cook" for 2 hrs as has been suggested in other threads. It showed no shorts but had low emission. I was able to rejuvenate it, and the pic seems a lot more sharper now. Horizontal is still unstable though.

Sync seperator voltages are off. Pin -4V. I have about 9 V. Pin 5 SB 275 & I have about 70. Early versions like mine use a 12SN7 for sync. Later versions use a 6SL7. I did sub a 6SL7 just to see anything would happen. Voltages were the same, and horiz was much worse.

This pic was tkane after the set has played for about 1 hr. Horiz still pulling

do you have a scope? a look at the composite video out of the detector would tell you if you have a good PP.

You can also try a direct injection of the comp video at the grid of the 1st video amp, that would clear the IF/tuner.

to be safe and avoid any DC issues a cap like a .1 should be used to isolate the set. I dont know if it has a hot chassis either so you would want to make sure about that.

What I do is check the chassis ground and the injection point with a volt meter to make sure there is no DC potential. If zero then you are safe to hook up. Just use the video out from the DVD box. Warning if you mess up and hook up to a screen for example (i did that once) you will smoke your modulator on the DVD or converter box. That is when I started to always double check for the DC before pluging in.

I have a RCA type connector cord with a couple alligator clips just for this.

it does not always work since its possible the signal could be inverted from what the receiver wants, and sometimes the PP is not right, but 9 times out of 10 it works.

one other thing to look at include AGC action (if adjustable). an adjustable AGC bias is very helpful to quickly eliminate that as a problem.

Video still looks weak, so, it may be agc problems.
Bill Cahill

Guys, I think I may have solved the problem tonight. Somehow, I have gotten hold of some mislabeled ceramic disc caps. I had 2 in my cap drawer that were labeled as 222. Yesterday, I went to replace an old 220 mica in the horiz osc section and grabbed one of these 222s. When I put it in, the horiz went haywire; no sync whatsoever. I then got out my Eico capacitor checker and found that 222 was actually reading about 2000mmf! I checked the other one in my drawer and got the same result. I had a 251 on hand and was able to get the mica replaced in the horiz osc.

Anyway, tonight I decided to retrace everything I had replaced in the sync section. I was going to check it off of my schematic of what I had replaced. I began looking, and there was another one of those bogus 222s coming off pin 3 of the 12SN7 sync sep tube. I then remembered that I had replaced that cap back when all I was getting was a horiz line across the screen. I took it out, and my Eico checker again showed about 2000 mmf. The closest I had on hand tonight was a 270, so I installed that in it's place. Therefore I actaully had a 2000mmf where there should have been a 220, even though the cap was labeled correctly.

That 220 that comes off pin 3 actually does tie into a 2000mmf which then goes to pin 1 of the Horiz oscil tube. I had never replaced that old 2000 mmf mica, but since I now have 3 on hand, I replaced it. Upon trying it, I was able to get a sharp and in sync pic. I only left it on for about a min. I'm going to give it a good test tomorrow and see if that fixed it. I would have never thought about some caps being mislabeled. I only recently got those too, but I can't remember where or when I got them.

Doug

Perhaps they're not mislabeled. The capacitor code on a ceramic disc is usually 1st digit, 2nd digit then # of zeroes. So 222 would be 2200 pF.

this is why I use my cap tester, everything that comes out gets tested, generally you can get some null reading of the eye,even badly shorted caps can generally get some kind of reading. Leave the dial and range switch alone, then put the replacement cap on the tester. You can quickly confirm two things, 1st that the new cap is good (I have had brand new shorted caps, those yellow tube caps) second that you are not WAY off like 10x due to a misread of the cap markings. Since you left the dial and range switch alone the new cap should null somewhere near the old, and of course confirm the indicated value per the cap tester to what you think it should be.

I don't recall ordering any 2200pf, but believe I did order some 220s recently. From now on I'll use my checker for verificatin. Thanks for the info.

Doug

Ceramic disc caps used in sync, and, horizontal osc. circuits isn't going to be very reliable.
For one, they tend to be +-80 percent. That means one,of two things, or, both.
First, when produced, they may be that high, or, low in actual value.
And, if not temperature co-efficient, that as they warm up, or, cool off, the value will change drastically.
These circuits are crittical.
Bill Cahill

Low-value caps like 220pF are likely to be NPO. It's the larger values that have the bad tempcos.

Dave Wise

Well my success was short lived. I turned the set on Thurs morning and had no horiz or vertical sync whatsoever. So far I've tried subing the 12SN7 sync tube, I got my substitution box and subbed capactors for the two I had replaced Wed (220mmf and 2000mmf), and that had no effect. I've replaced almost everything in the sync circut, and what I haven't replaced ( a couple of resistors) checks good. For me to get any type of pic the horiz freq con horiz hold have to be maxed out, and even then sometimes that's not enough. The pic I get shows multimple images moving side to side. I've uploaded a pic.

Doug

Have you worked through the full procedure in Sams for adjusting the horizontal frequency? Page 19 in Sams 78-7.

As Bill noted earlier, your picture also looks pretty washed out -- dim, with poor contrast. If you're photographing with a flash, that will wash it out, of course, but if not, your video section may need attention. Have you ever tested that CRT? A very weak picture tube can also look dim; cranking up the brightness & contrast controls won't give you a picture with deep contrast, and it may even result in a sort of negative image.

What are you using as a signal source? A weak signal may result in weak sync, causing problems in horizontal and/or vertical sweep. Some old TVs behave quite differently with different sources, especially if the automatic gain control (AGC) section isn't up to snuff.

Just a couple of quick ideas . . . .

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

Phil, I have not tried the Sams adjustment yet. Thanks for letting me know about it. I tested the CRT a few days ago, and it was low on emission. I was able to rejuvenate it howerver, but I think I'll put it on the checker again. Yes, I am using a flash on my phone when I take the pics. The pic on the CRT actually looks better than what I upload. My signal source is my cable. I've quit using the VCR except in the very early stages of testing a set where I don't expect to much in results. After going thru a hassle with that VCR when I was restoring my Motorola VT-73, I learned it's better to use the cable rather than a VCR.

I'll go thru the Sams tomorrow and post the results.
Doug

Also, on most of these old sets the contrast control is in the agc circuit. If you turn down the contrast, it will lower the agc signal to the set.
Looks like you may have a horizontal oscilator problem.
Tube might have gone bad, or, leaky micas, or, bad resistors on horizontal oscilator tube.
Bill Cahill

I fought with it for over an hr last night and gave up until tonight.
Bill, your theory on the horizontal oscialtor makes sense, but I have replaced all micas and paper caps in the horiz osc. I've replaced all resistors except 2, and they check good. I've tried a couple of other 12SN7 tubes in the oscilator. There was one cap that I has missed, a 1200mmf, and I replaced it last night, but that didn't help. My voltages on the horiz osc tube are all fine. Pin 5 Sb about 240-245, and I have about 220 according to my VTVM. I can't check that with my digital meter.

I read the horiz freq adjustment in my Sams, as Phil suggested. According to it, the pic needs to be in full horiz sync, then touched up with these adjustments. However, I can't get it in sync for more than a second before it loses it. It's just several images on the screen moving side to side.

I still think the problem may be in the sync circut as I can't get the vertical to lock in either. I've got all caps and resistors replaced the the sync circut, but have some voltages on the 12SN7 sync tube that are way off.

You use the horizontal adjustments to get the point that it syncs, or comes close to syncing, to be at the center of the range of the horizontal hold control. If you can adjust the horizontal hold to the point that it almost syncs, and that is not at the end of the range of the control, then there is no problem with the horizontal oscillator.

If neither the horizontal or the vertical will sync, then the problem is in the sync separator.

Tom, the horiz hold has to be at the end of it's range for me to get any type of pic, even multiple images moving across the screen. After the set heats up, I can't get any horiz sync at all.
The block diagram shows that the Video output tube 12AU7 feed the sync seperator. I checked the voltages, and they are ok, but sync voltages are way off.

Then you can adjust the frequency adjustment to move that almost sync point to the center of the range of the horizontal hold control.