SCPH-1001 intermittent disc reading
Posted: May 18th, 2022, 1:38 am
Hi there, first off I'd like to thank this forum for all the help you guys have given so far. That said, I'm having enough of a rough time with my friend's old PS1 to make an account and post so here goes.
Basically I have an MM3 chipped PU-8 board PS1 that only reads official or burned discs on the first startup after being off for a while. At this point I'm fairly certain is has to do with the laser and pot adjustments, it was reading official discs fine there for a while but after adjustment it has a hard time with those now too. I've worked with a soldering iron in my hand everyday for the better part of 10 years now so I've tried a number of things so far:
- Recapped entire PU-8 board and verified capacitances
- Recapped power supply and verified capacitances
- New spindle motor/laser assembly
- Swapped old working laser into new sled assembly
- Multiple calibration attempts on bias/gain (I tried multiple values between +-0.1V off 1.70V bias and 1.85V gain)
- Vpp = 1 to 1.2V via scope on the laser pot, tried for both official and burned discs but reset back to ~1.1Vpp with laser at mid-disc on an official disc
- Multiple disc re-burn attempts with verbatim CDs (it managed to load Crash up to the level select screen once)
- Verified lens clarity and alignment
I suppose it could be an issue with the modchip but based on what I've read it seems more likely to be a disc reading issue, seems like something is heating/charging up somewhere and once that disspipates it has an easier time reading discs. It'll usually boot a game on the first start but then crap out a few minutes in. Below is a pic of my modchip installation in case anyone sees something wrong or if I soldered to the wrong trace somewhere but seeing as how burned games do boot I doubt it's the issue. I'd attach the full resolution pic but it's rejecting it for size despite it being under 3Mb, weird. I've found so little official service documentation so I've been going off user-reported voltages and tips but I'm kinda stuck for now and I'd rather not buy a disc drive emulator, lol. Any help is appreciated, thanks for reading.
Basically I have an MM3 chipped PU-8 board PS1 that only reads official or burned discs on the first startup after being off for a while. At this point I'm fairly certain is has to do with the laser and pot adjustments, it was reading official discs fine there for a while but after adjustment it has a hard time with those now too. I've worked with a soldering iron in my hand everyday for the better part of 10 years now so I've tried a number of things so far:
- Recapped entire PU-8 board and verified capacitances
- Recapped power supply and verified capacitances
- New spindle motor/laser assembly
- Swapped old working laser into new sled assembly
- Multiple calibration attempts on bias/gain (I tried multiple values between +-0.1V off 1.70V bias and 1.85V gain)
- Vpp = 1 to 1.2V via scope on the laser pot, tried for both official and burned discs but reset back to ~1.1Vpp with laser at mid-disc on an official disc
- Multiple disc re-burn attempts with verbatim CDs (it managed to load Crash up to the level select screen once)
- Verified lens clarity and alignment
I suppose it could be an issue with the modchip but based on what I've read it seems more likely to be a disc reading issue, seems like something is heating/charging up somewhere and once that disspipates it has an easier time reading discs. It'll usually boot a game on the first start but then crap out a few minutes in. Below is a pic of my modchip installation in case anyone sees something wrong or if I soldered to the wrong trace somewhere but seeing as how burned games do boot I doubt it's the issue. I'd attach the full resolution pic but it's rejecting it for size despite it being under 3Mb, weird. I've found so little official service documentation so I've been going off user-reported voltages and tips but I'm kinda stuck for now and I'd rather not buy a disc drive emulator, lol. Any help is appreciated, thanks for reading.