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#1
12-28-2007, 04:32 AM
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Montgomery Ward problem
Finally I have a real question to ask…
This guy in my building has this Montgomery Ward TV that’s lost horizontal hold. He told me when he found the set, it had the same problem, he took it to a friend and the guy replaced the tuner. The guy replaced the tuner and the TV set worked but afterward, he said it would lose horizontal hold and come back after being on for 5 minutes, now the set won’t normalize. I went by his place and it’s doing exactly what he described. At first I thought maybe the yoke or horizontal amplifier went, but I notice that the OSD is displaying text on the screen with no problems, that leaves me to think it’s the tuner… The set is connected to the house’s cable, when I disconnected it, it would regain horizontal hold and display snow. The set is 27” branded as Montgomery Ward, however the picture tube is made by Zenith. I’m not sure where to start looking since its showing signs it’s the tuner… 
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#3
12-28-2007, 06:46 AM
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try it with off the air reception...if it works off the air....investigate ground loops in the cable circut.
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DIY Belle's, LSI , Heresy's, Khorns, Marshall 9200, 9100, el20/20, Dyna Mk VI's, MC2000, SF FL2, C1000, EAD 7000 III, MDA1000, Onkyo NAS, MS300;
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#4
12-28-2007, 11:11 AM
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If the OSD is displaying properly even while you're seeing the tearing lines then the oscillator is probably not at fault. Strange condition.
I agree to try it from off air VS cable. You might also look to the sync sections to see if you are getting all sync pulses to the vertical and horizontal oscillators. Great mind bending project to improve your troubleshooting skills, but normally I would just leave a set like that at the curb.
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Jordan
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#5
12-28-2007, 01:31 PM
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I had a cheap 19" Zenith that same age, a curb find. On weak stations it worked fine but tune in a strong one and the horizontal would got out. I touched up the soldering, especially on the coils, and replaced a few caps. The problem never got better and since sets like this are basically worthless now I just tossed it.
I strongly suspect that this is a rebranded Zenith-the cabinet looks like it.
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Bryan
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#6
12-28-2007, 03:34 PM
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That is a rebranded Zenith. It looks like the CRT may be OK; so, it may be worth saving just for the tube.
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#8
12-28-2007, 07:53 PM
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Check the B+
Some sets pull the horizontal off frequency if the B+ is too high. I seem to recall some electrolytics failing and letting the B+ rise. I don't know if your model is one that does this but it might be worth a look. That would also fit the OSD staying in sync when the video is out of sync.
This does look like a rebranded Zenith to me too.
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#9
01-03-2008, 06:40 PM
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I’ve tried the TV with an over the air antenna and its doing the same thing. Today I took the set apart and looked at the main board for obvious problems. Then I plugged the set in and turned it on and a resistor near the flyback started smoking.
 What do you guys make of this? It wasn’t smoking before
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#10
01-03-2008, 06:52 PM
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You have a short causing the resistor to burn. You'll have to follow the foil from the resistor to see where it leads. That diode right next to the resistor would be the first thing I'd check.
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#12
01-03-2008, 07:10 PM
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Quote:
I suspect that diode in your set either feeds the vertical circuit or the 200 volt supply to the video output stage. If it feeds the vertical circuit, the vertical output IC may be shorted.
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Linear Mode
