Screen on PC Engine GT stays very dim for about 5 minutes??

[8 Bit]

I recently replaced the caps on my PC engine GT and have it working somewhat now. When powering on the GT the screen stays very dim for about 5-8 minutes then starts working great until I power it off for an extended period of time. After that I have to wait 5-8 minutes for the screen to warm up again.
What could be causing this? The brightness dial seems to be working fine, it's as if the back light is just not getting full power until its powered on for 5-8 minutes.

[Keith Courage]

Old capacitor leakage either in via holes causing shorts or old capacitor leakage got underneathe various components causing shorts.

For via holes, the solution is to do what you did to fix your pulled up pad. Run a solder lead through said hole and solder to both sides.

For leakage under components causing shorts, you have to de-solder said part from the board, clean the board and part, then re-solder back to the board again.

There is the minimal chance that it's actually the screen at fault, but that's extremely unlikely.

[8 Bit]

Okay, thank you. Could I use a voltage tester to narrow down which component/hole it might be? Everything looks good visually now, and I only had 1 capacitor that had leakage that I noticed before doing the recap and that didn't seem to have made a mess.

[Keith Courage]

Check the voltages of capacitors before it starts working correctly and after.  That might help you narrow down what vias or components are shorting.