Search found 7 matches

by mgarnett
Fri May 17, 2019 11:21 pm
Forum: HARDWARE ISSUES
Topic: Atari TT Repair
Replies: 7
Views: 554

Re: Atari TT Repair

Thanks, appreciate the advice.
by mgarnett
Fri May 17, 2019 11:02 pm
Forum: HARDWARE ISSUES
Topic: Atari TT Repair
Replies: 7
Views: 554

Re: Atari TT Repair

Yeah sorry, I mean the PSU is on and there are correct voltages coming out of it and I’ve tested many of the ICs and they appear to be receiving the correct voltages. Just nothing happens on screen, no HDD activity and no floppy activity so something is failing before any of that even starts. Thanks...
by mgarnett
Fri May 17, 2019 10:55 pm
Forum: HARDWARE ISSUES
Topic: Atari TT Repair
Replies: 7
Views: 554

Re: Atari TT Repair

Power supply repaired and the machine powers up, but to a black screen.

Damage was obviously more severe.

Troubleshooting time! I’m going to start going through the service manual procedure but additional advice always welcome if there’s other things I need to watch out for.

Thanks

Mark
by mgarnett
Sat May 11, 2019 8:46 am
Forum: HARDWARE ISSUES
Topic: Atari TT Repair
Replies: 7
Views: 554

Re: Atari TT Repair

For information, have been told by another TT owner that without a PSU installed, the resistance from 5 volt to ground on the motherboard can range from 25 ohms to about 160 ohms depending on what hardware you have installed, so his resistance appears to be normal.

Cheers

Mark
by mgarnett
Fri May 10, 2019 10:51 pm
Forum: HARDWARE ISSUES
Topic: Atari TT Repair
Replies: 7
Views: 554

Atari TT Repair

Hi All, I am repairing a TT after a power supply failure where the fuse exploded and several diodes failed in the supply. Before installing a new supply I wanted to check to make sure there were no shorts on any of the power pins and on the motherboard. I checked the power connector on the motherboa...
by mgarnett
Wed May 08, 2019 9:36 am
Forum: PSU (power supplies)
Topic: Atari TT PSU Repair
Replies: 3
Views: 364

Re: Atari TT PSU Repair

Thanks Exxos,

I’ll replace all the caps, the two diodes, and the switching transistor if it tests bad. I’ve also ordered a new PC111 opto chip as well just in case....I wanted to try and rule out everything before powering it back up and testing it so as not to blow it up again!

Cheers

Mark
by mgarnett
Wed May 08, 2019 8:19 am
Forum: PSU (power supplies)
Topic: Atari TT PSU Repair
Replies: 3
Views: 364

Atari TT PSU Repair

Hi All, I turned on my TT the other day and there was a loud bang from the machine which was the fuse blowing in the PSU. It blew up quite violently, glass shards everywhere. I took the supply out and examined it and I could see that there was some charring on the PSU connector that connects to the ...