PC engine GT help needed

[shak1ra]

Hello all long time TGrafx owner and fan. I am currently working on a turbo express and a pc engine GT. the questions here are related to the pcgt. I have replaced all the caps with smd caps. I have double and triple checked orientation and all connections appear good. Problem i am having is the console will not power up. I replaced the fuse witch was bad and i now have power at the plug going into the board. But thats all. I back probed the fuse solder points and i have continuity thru the fuse. But i have no measurement of voltage. Any ideas? I have read thru the forums but have not found anything that could help me with this. Thanks in advance

[shak1ra]

I have around 9v at the plug going into the board. I plugged the ac adapter and still does not power up but the voltage at the fuse comes up to around 2.5v. Hope this helps.

[Keith Courage]

I had this problem once. Turned out one of the the 100UF 16V caps for the video had a broken trace. Use a multimeter to make sure all the caps have voltage.

[shak1ra]

Hi thanks for the response. Here is where I am at now. I only have .25v at cc101 and .20 at cc102. I have no voltage at any other caps. I now have 9.5v at the fuse and 1.25v at the rear if the ax adapter. Hope someone can help further feels like I am close but.... We will see.

[Keith Courage]

.25v? I hope you accidentally put the decimal point in the wrong place. That is way too low. Most of the caps on the board push 5V. Others range from 2.5V to 7v.

[shak1ra]

Nope I was right all other caps are asleep. How do I trace where he power goes once it leaves the fuse?

[turbokon]

Try swapping out the controller board with the working express..

[shak1ra]

Sorry to sound like a idiot but what exactly do you mean by controller board? thanks

[shak1ra]

K never mind the above post. I took the controller board from the Turbo Express and replaced the cap and installed it and nothing. I also did the same with the PC Gt board that cap was absolute crap. Same thing nothing.
Kinda starting to feel like these guys may be dead.

[shak1ra]

So after continuing investigation into this matter I found something this morning. Apparently there is a resistor that was blown off the board when the caps were being removed. Does anyone know the value of resistor r723? Thanks

[turbokon]

That is just a jumper resistor to ground pin 29 on the turbo express. The GT won't have that.

[shak1ra]

wow thanks so the board on a GT will be blank there right?
still not working tho. is there a list here of what the cap voltages are supposed to be? I am bound and determined to save these systems.
thanks.