Vertical Collapse on Sanyo EZ20

[zinger]

I recapped that monitor and I now have the dreaded vertical collapse problem.



So far I have checked all the caps, fixed one bad solder issue (which is likely the culprit), replaced TR402, TR403, replaced the IC LA1464, and replaced a bad resistor at R216 which looked like it exploded.

I'm looking closely at the schematic that controls vertical and have a bunch of things to still check. Looksl like R414 is interesting one to look at next. Any other ideas?

[behrmr]

Have you checked to make sure your test switch on the chassis isn't in the test position?

[zinger]

Yeah, that was the first thing I looked at. It's in the "normal" position. I tried flipping it to the service position to see if anything looked different and it doesn't.

So now I'm looking at all the obvious stuff in the circuit.

[zinger]

I started testing all of the resistors and actually found a bad one at R473. Replacing this fixed the problem! Now the monitor seems ok but now I'm not getting anything from DK board. It seems there are two caps on the DK board that have gone bad. I wonder if these could have gone bad when the Sanyo smoked and maybe caused a spike across the video signal cable? I'm not hearing any audio either.

I could really use a pattern test generator right now just to verify the monitor is good.

The follow pic looks good in person. That's the vertical refresh and I also have the brightness turned up.


Here's the bad resistor.

[zinger]

Just following up here with latest image on Sanyo monitor after fixing multiple issues with it (e.g. it being dead and then having vertical collapse). After fixing that and then the data bus issue on my DK board (bad LS240 IC at 4N) then I could finally see a proper image for first time on this monitor! 



I have another Sanyo that is completely dead too. I'm going to try and bring that one back to life now.