hmmm maybe better to try feeding the composite video thru a cap like a .5 or so to the base of the 1st video transistor would do it. that transistor is prob on the IF board but not sure. I imagine there is a transistor layout sheet somewhere pasted inside the cabinet. All converter boxes have a composite video, just use a RCA jacked cable connect the shield to the chassis and the center lead thru the .5uf cap to the base of the 1st video amp transistor. You would still need to unplug the tuner IF lead to get rid of any snow. I do this a lot when trying to isolated video problems.

I think what you are saying is to split the composite video connection to both the .5uf cap and the 1st video transistor. I looked at the layout sheet inside the cabinet. I can only find 2nd and 3rd video transistors. I couldn't find the 1st one. I don't know where to begin looking for the capacitor. I think I will just give up and leave the picture as it is. I might take it to a repairshop. If he cannot fix it, he might be able to at least find out what part is bad.

You need a .5 cap, use it as a probe, attach to the base of either of those transistors. The cap is to isolate the composite video source from the TV in case there is any DC potentials on the transistors. connect a .5 cap to the center lead of the cable from the composite video source, the cap will pass the signal but will block DC. You need to be careful around solid state stuff, one slip and you can smoke a transistor, they are not as forgiving as tubes.

The transistors have 3 terminals. Can I connect it to any of those terminals? Also do I leave the transistor hooked up, or do I leave it out?

connect at the base the middle on those. Be careful not to short anything in the process use the cap and start at the base of the 2nd video amp on those. if the ghost is still there go the the 3rd video amp base (center of transistor) if still there then that would indicate that the problem is AFTER that injection point which would leave the video module. If the ghost is gone then the problem is ahead of the injection point, pointing to the IF or tuner. Again make sure the cap lead does not short (momentary contact between the base leg and anything else).

Normally I would just hook up a patter generator and use a scope to examine the video signal but I know you have limited test gear so this is the only way I can think of to try and get somewhere with just a DVD box. You should be using the "video" jack on the box, there are L and R audio but this is just a video test so clearly there will be no sound.

You need to make sure there is no signal coming from the tuner so see if you can unplug the IF lead (should be a cable with an RCA type plug. if you cant find it you can still plug to the test but the snow may make it hard to examine the pic for ghost.

oh and leave it in

How do you recommend connecting anything to the base of the transistor with it still in? Would I have to stick a paper clip in there? Also, is it essential that I do not make contact with the other two terminals on the transistor, just the one in the middle? I want to make sure I don't short it out.

yes it is essential not to make contact with anything else but the middle. as far as how to do is up to you. I would recommend you get one of those special DMM prob tips that you can buy at radio shack the fit on the ends of test probs, and are useful for clipping onto leads. Not alligator clips, but rather a J hook device that retracts into a protective plastic piece.

I concure with an earlier comment re capacitors. Look for smaller electrolytics that show signs of leaking and drying, puffed out, or crusty. A bad cap may look fine as well. In years gone by most of the really strange symptoms on an otherwise working set turned out to be dried out/ open caps. What ever you do do not adjust anything on the IF module.

My gut instinct tells me that I'm going to run into a lot of trouble if I test it this way. I think I will just leave it the way it is until somebody can look at it who knows what they're doing. The TV is almost 40 years old, so at least it still works.

Dave,

Thanks again for fixing the horizontal. The picture does not shake at all since I put in the module.

If you are feeling uncomfortable, then for sure back off. You will find someone help you eventually. My 1st rule is to do no harm.

I found someone to work on the set! He didn't do any complicated test work. He just adjusted a few dials on the back and noticed that the focus adjustment made the picture lighter and darker. The first thing he told me was to replace the focus dial and if that doesn't work, try a different tripler. I am going to try the focus and see if that works. I found one for $5.00.

Hello Guys,
Also go through and remove the boards and use a eraser and clean the contacts the connect the boards they had intermintent problems with these sets I wish I was on the coast at my old home I have the factory service manuals for this set

I did what the repairman said. I tried replacing the focus dial and the tripler. Neither of them worked. That was surprising because he knew quite a bit about this chassis and used to work on these televisions. It seems to have narrowed down to what most people here have been saying, a bad electrolytic capacitor. I don't even know where to start looking for the bad capacitor, and my meter is very innacurate when it is set to ohms. It looks like I will just have to leave this TV as is.

Since I couldn't determine where you are located I couldn't refer you to one of the NESDA member shops who COULD repair the set. There are a couple of members who love working on the oldies.

If you were in WA state, I'd be happy to look at it for you & I still have boxes full of Zenith parts & modules.

I am in the Chicago area. I do know of one repairshop around here that works on these, but it is so heavy, and I don't intend on moving it back and forth. They would probably charge a small fortune to repair it anyway. If somebody nearby is willing to come over and take a look at it, they are welcome to.