Hi all,

I was given a 14" colour SANYO CTP3620N from the 1980s by Nathan Brown, which was working pretty good. I decided to clean it up today, and hosed/scrubbed the case, vacuumed the layers of dust off the circuit board, and wiped the tube/yoke with some cleaner and a rag.

However, ever since that, it's been constantly playing up, with different symptoms when I adjust it. The most prominent issue seems to be horizontal convergence, colour/purity issues and green/red stripes and shadows on the image.

Does anyone have any thoughts on how to fix this, as it is a great little sets and now one of my favourites. I've never had this issue after cleaning a set before, so it's left me dumbstruck. No trim pot/pot adjustments or convergence/focus ring adjustments seem to cure it.

Here are the details:

SANYO
Model - CTP3620N
Service Ref. No. - CTP3629N-00
Serial no. 34902403
Chassis - 83P-D14
Gen details - ~240V 50Hz, PAL B/G

Chris

Bad caps maybe? And have you finished work on that monitor?

‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾
"I'd rather have a CRT than nothing" - me
"people just throw working CRTs out, it is NOT FUNNY!" -me

Yeah, I've almost finished. I have a theory as to screen resolution being the cause of the decreased horizontal deflection, but I've yet to test it out (too much school work, too little time).

Chris

It's certainly not happy looking but it's hard to pin down by your pictures.

The first test to do on any colour TV with colour problems is to turn the colour control to minimum (colour turned off).
This will let you see what the set does with only a black and white image. If you still see coloured fringing and streaks chances are you've messed up the CRT convergence somehow.

If you have a perfect B&W picture then the CRT is fine and the problem is on the PCB somewhere.

The colour still shows with the colour pot turned down, but the convergence adjustment rings on the neck of the set only improve the vertical convergence - the horizontal convergence is still messed up pretty badly.

Chris

Hmm, looking like a convergence problem then. At this stage make sure the wedges under the yoke (if fitted) are still in tight. If any are loose, you may have disturbed the yokes position.

I'll read up on PIL CRT convergence procedure again and post back later.

Thanks for that, I'll take a look inside it now.

Chris