DC Potentiometer issue / Dodgy laser

[mattjeh]

I just bought my first DC recently, 3 games tried and played without issue. SonicAd2, Tomb Raider and MSR. I took it apart to clean, all carefully disassembled and re-assembled. Then, only Sonic works and the others get the ‘please insert game disc’ message.

I’ve been using an Ohmmeter to adjust the POT with mostly poor results. Sonic continues to work through the KOhms range from 0.61 to 1.48 (in 16 steps - 0.61 / 0.65 / 0.75 / 0.83 / 0.89 / 0.97 / 0.99 / 1.00 / 1.01 / 1.03 / 1.08 / 1.14 / 1.18 / 1.23 / 1.34 / 1.48).

MSR booted up once at 1.01 (as well as sonic), but tomb raider still doesn’t. After continuing to test through the range, I returned it to 1.01 and MSR subsequently doesn’t boot once again.

From what I understand, original game discs should be fine throughout this range. Has a (gentle) dismantle and re-assembly possibly damaged something in the laser assembly, as games previously working, suddenly don’t anymore?

I’ve not been able to clarify anywhere the default factory KOhms reading (I borrowed the Ohmmeter I have after I made adjustments so I didn’t record what it was originally, like a dumbass).

Can anyone give me the default reading or advise what I can do moving forward to fix this? Or do you think the laser assembly is full on knackered?

Please help, there are cookies in it for you. Thanks.

[Anthony817]

Damn that sucks. I used to have to tune mine when I had issues over the years, but I never used an Ohmmeter. I am on GDEMU now so can't really help there, but once I lost my position on a DC before when tuning the POT and I had to keep turning back and forth until I had luckily found a range that it could read games at again.

I am so done with discs now and having issues as my last 2 DC's completely were kaput, so I got a GDEMU and haven't been happier.

All I can tell you is to just try and figure out where it was originally. Isn't there some rel lacquer or something on it that would show you the general area it was lined up at before tuning it?

[Xiden]

I just bought my first DC recently, 3 games tried and played without issue. SonicAd2, Tomb Raider and MSR. I took it apart to clean, all carefully disassembled and re-assembled. Then, only Sonic works and the others get the ‘please insert game disc’ message.

I’ve been using an Ohmmeter to adjust the POT with mostly poor results. Sonic continues to work through the KOhms range from 0.61 to 1.48 (in 16 steps - 0.61 / 0.65 / 0.75 / 0.83 / 0.89 / 0.97 / 0.99 / 1.00 / 1.01 / 1.03 / 1.08 / 1.14 / 1.18 / 1.23 / 1.34 / 1.48).

MSR booted up once at 1.01 (as well as sonic), but tomb raider still doesn’t. After continuing to test through the range, I returned it to 1.01 and MSR subsequently doesn’t boot once again.

From what I understand, original game discs should be fine throughout this range. Has a (gentle) dismantle and re-assembly possibly damaged something in the laser assembly, as games previously working, suddenly don’t anymore?

I’ve not been able to clarify anywhere the default factory KOhms reading (I borrowed the Ohmmeter I have after I made adjustments so I didn’t record what it was originally, like a dumbass).

Can anyone give me the default reading or advise what I can do moving forward to fix this? Or do you think the laser assembly is full on knackered?

Please help, there are cookies in it for you. Thanks.

So it could actually be a bad power supply too.. This video may help. I think many people that think they have bad bad lasers, it wasn't actually the laser problem but bad caps on the psu. Make sure your GDRom is even shooting a laser out to begin with.

https://www.youtube.com/watch?v=ilhfndjs6ew

[mistamontiel]

That guy in that YT has NO FEAR! No discharging power no letting them sit few hours before playing with o.0

Very interesting thanx for the share!

[mattjeh]

All I can tell you is to just try and figure out where it was originally. Isn't there some rel lacquer or something on it that would show you the general area it was lined up at before tuning it?

There is a little sort of splodge of red stuff, but nothing to indicate where it was. The increments are so tiny for a small increase or decrease that it's like a needle in a haystack when just looking for it blind.

So it could actually be a bad power supply too.. This video may help. I think many people that think they have bad bad lasers, it wasn't actually the laser problem but bad caps on the psu. Make sure your GDRom is even shooting a laser out to begin with.

https://www.youtube.com/watch?v=ilhfndjs6ew

I'll take a look at it, but it must be possible to rule out an issue with the psu if I can play sonic 2 without any issues at all.

I've pretty much given up at this point and decided to buy another unit. I'll probably end up selling this one on as faulty/for parts.