Hey guys, I'm regrettably new but would like to say thanks for letting me join. I often repair systems, and would say my level is at least up to snuff. I recently had a friend ask me to repair his turbo express as the video worked but produced no sound(someone had replaced the caps before and did a poor job, also replaced the fuse). I replaced all the caps on the boards that were SMD cans(not the small rectangular ones) OR electrolytic. Fuse popped when turned on, replaced it. Sound works perfectly, video no longer worked. All I was able to see was a black backlit screen. I did research that suggested the Q900 & Q901 were toast. I ordered 4 new transistors from mortoffgames and installed them. Now i was getting no backlit at all(everything here to the beginning was run off batteries new from the package). I decided to try an Atari lynx power supply to see if the batteries were the issue(the lynx supply isn't far off from the turbo ratings). First Q901 completely smoked and burned, i decided to put one of the original transistors back in place(no more smoking in the area). Now the transistor at Q500 started smoking, but it seems intact still. This sounds like a bad component or 2, or voltage is messed up. I looked around the board and removed the grey goo around the or area(moron who first replaced the fuse scratched the top of the board getting it off, i checked everything i could and traces seem intact) to see if anything was wrong there. I found one of the inductors(L502) is broken and have no idea what that could do or what the replacement would be. I checked VR501 and get a max of about 2.35 V out of it. I need a schematic but it seems this is nonexistent. Short of that, does anyone know 1.) where the power regulator is 2.) what measurements i should get across VR500&501 3.) if the transistor in the Q901 spot is a correct replacement for the stock one I have currently in the Q900 spot 4.) what is the replacement part for L500 or how to test it? 5.) what the replacement for Q500 is called? Any help would be greatly appreciated, and from what I've read thesteve is the most qualified to tell me I'm an idiot. Also what's the best way to show pics of the board through here, perhaps if someone could send me a pm about the pics to not muddle up the topic?
Topic: Turbo express weird issues(after cap replacement) (Read 255 times)
