PC Engine GT problems...

[PCEngineTrev]

Hey people,

Im new to the forums here, and Ive only recently got into the wonderful world of the PC Engine, I cant believe Id overlooked this awesome console for so long! Ah well, better late then never I guess....

Apologies for making my first post about a technical issue which may have been brought up a million times before, but my own research has failed to give me a firm answer.

I have a GT that I managed to buy off a friend with little interest in keeping old consoles. It has a couple of issues, one being the typical low sound issue, but this is also combined with purplish black screen when turned on. Reading previous posts on the forums showed this to be a common problem, but I managed to work around it by using an adjustable power adapter and setting the voltage at 12V. When running off the 12V setting, the GTs screen works perfectly, albeit with the low sound. I know GTs normally only need 7V of power, yet mine seems to require 12!? This of course means that I cant use batteries on it at all, this wont provide enough power anymore and just leaves me with the low sound and the purplish black screen.

What has caused the GT to require 12volts now? And does this mean that my GT is on its last legs??

Any insight would be appreciated guys, thanks....

[grahf]

Welcome. The GT board itself is probably fine, but the screen module is on its last legs. Since all the ICs run on 5v, power for the board runs through a small SMD voltage regulator. It only requires 7v, so feeding excess voltage into it will cause it to produce more heat as a byproduct (as is the nature of linear regulators). An extra volt or two shouldnt be a problem, but I wouldnt trust it because it doesnt have a heatsink. Its merely mounted to the board, and dissapates heat onto the PCB.

I havnt done much testing, but from poking around it appears the screen gets unregulated power. There is a transformer on the main board that ups the voltage to the high level that the light in the screen needs. Feeding a higher initial voltage into the regulator is producing an even higher output voltage. Its seems your screen may need a little more jolt to work, if the bulb is going bad.

This is all just speculation since I dont have anything in front of me to test. Your first step should be to try finding another GT or Express and swap the screen module. See if another screen works off of the normal 7v input. If not your problem may lie with the transformer on the board, or a supporting capacitor, etc.

[PCEngineTrev]

Yeah that sounds pretty reasonable to me. This sound issue isnt really a problem, and it plays hucards fine, even the unit itself is in pretty good cosmetic condition. The screen is the main problem, with its power demands. I dont want to keep running the GT with 12volts as this is surely bad for it over a prolonged length of time. I have a friend who repairs electrical applicances, so I might hand it over to him and ask him if he can see anything wrong with the screen and how it handles power.

Could the screen issues have something to do with the power supply the previous owner used with it?

Thanks for the feedback by the way, v.helpful!