Zenith Sentry 2 TV, weird problem with the horizontal.

[MRX37]

My latest find is a 1992 Zenith Sentry 2 19" TV. When I first found it I thought "uh oh, 90's Zenith... CRT's probably shot.

Nope, the CRT seems to be fine. The horizontal isn't right though. The picture looks scrambled.

I want to fix this TV, cos I have a feeling it was probably one of the last Zenith's made with a decent CRT...

I'll provide a model # and images later.

[radiotvnut]

Some of those Zenith's had a 2.2 (IIRC) uf cap going from pin 2 of the jungle IC to ground that would cause horizontal scrambling, tearing, lines, etc.

[andy]

...

[MRX37]

As promised:

The model# is SS5045Y

And here's a pic of what it's doing:



On strong channels, it seems to only do it intermittantly.

[radiotvnut]

That looks like the symptoms of that 2.2 uf cap.

[MRX37]

Okay. I'll start testing caps soon. This TV's actually gone to the back burner, as i found another one that's actually worth something if i can fix it.

[MRX37]

Changed my mind and started testing caps. Found one bad 100uf cap and replaced it... and the problem worsened! The bad cap measured at only 35uf while the replacement was a good cap.

In any case, is the Jungle IC a huge IC, or is it smaller? A pic of what it looks like would help.

EDIT: This TV has mostly black caps. there are a few light blue, which I have repl;aced. No burgendy caps though.

[radiotvnut]

The jungle IC is the rectangular black chip with anywhere between 52 and 64 pins on it. It will probably be located somewhere close to the tuner.

The other big chip is the microprocessor and should be located close to where the front panel keypad plugs in.

What module number is in this set? It should be a 9-xxxx and will probably be printed on a label in the back of the set?

[MRX37]

The module number is 9-1118

So the Jungle IC is a big IC, that narrows it down. That 100uf cap I replaced was near a small IC.

[radiotvnut]

That jungle IC will likely have an LAxxxx part number on it. The microprocessor will probably have some strange combination of letters and numbers on it.

[MRX37]

Originally Posted by radiotvnut

That jungle IC will likely have an LAxxxx part number on it.

Nope. Only two IC's that fit the description of the jungle IC, and neither has a LAxxxx part number.

[andy]

...

[MRX37]

If it'll help, here's what's written on both of the large IC's:

First IC:

221-679
Sanyo J9139 1JE0

Second IC:

221-685-02
130 J9148 (c) ZENITH 91

[radiotvnut]

It's the first IC (221-679). It's the same as an NTE7054. Pin 30 is where the B+ enters the IC for the horizontal oscillator / drive circuit. Check any caps that connect to pin 30.

[MRX37]

O...k... How do I know what pin is Pin 30? I don't remember how they're numbered.