Nanao MS8-26SU Vertical Issues

[MonMotha]

I'm attempting to repair an MS8-26SU from a Daytona USA.  Initial symptoms were some foldover at the top and occasional vertical collapse.  The top half seems much more susceptible than the bottom half.  In fact, I'm not sure I've ever seen the bottom half go away.

It seemed to be possibly susceptible to vibration, so a cold solder was suspected.  Upon inspection of the vertical area, several possible cold joints were found and touched up.  Now it powers up with the top half totally collapsed, but the bottom half works.

The area around the vertical transistors has obviously seen some heat.  Can anyone comment if this is normal or potentially another symptom?

I'm beginning to suspect a possible bad transistor, but other thoughts are welcome.

[grantspain]

most common issue on these monitors
check/change the following
C433 R433 R436 Q401 Q402 C437

[mgb]

definitely like said above.
this seems to be a most common area of repair on these.
I had vertical collapse on one and it was the two resistors that were it R433 ( 2.2K 1/4w ) and R436 ( 15K 1/4w )

[MonMotha]

I'll check these, thanks.  Anybody have a schematic I can use as reference?

[mgb]

If I remember correctly this was a tough monitor to get a manual on.

[MonMotha]

Well, I can do it blind if I have to.  I've got a bunch of Toshiba monitors from the late 90s that I'm in a similar boat with.  I've slowly been cribbing up notes on good test points and expected voltages.

Anyway, I'll check those parts.  It sounds like people know this particular fault reasonably well.

[mgb]

Yes, when I had one of these with a similar problem, every thing I found online talked about the same parts and those 2 resistors did it for me.

On the klov forums, there's info on this from Modessitt, who has dealt with this a few times