PC-Engine CD-ROM2 Laser problems?

[yesimnathan]

I'm so glad that I found this post! I spent the better part of this evening trying to tweak the pots on my CD-ROM2 with very little success. When I initially received it, it wouldn't read any discs at all - even audio CDs. It would do one quick burst spin of the disc & then nothing. Popped it open & the middle gear looked fine & the lens carriage moved pretty smoothly. Ultimately, I came to the conclusion that it must be a dead lens.

I bought a Sony Discman D-34 & quickly harvested its lens. After swapping that out, the CD-ROM2 started coming to life. It started to play a burned copy of Rondo flawlessly. It ended up crapping out about 5 mins in. I started playing with the pots referencing cran's post here: http://assemblergames.com/l/threads/please-set-disc-on-turboduo.53989/. After several hours of tweaking, I've got audio CDs playing well now but even legit PCECD games take FOREVER to load and the audio promptly cuts out shortly after starting. I'm beginning to think that this is all moot & no amount of potentiometer tweaking is going to help until I replace the caps.

Anyway, the main reason I wanted to contribute to this thread is to let you know that I have 2 TurboGrafx CD drives that generally work well (one better than the other). They both suffer from the audio cutting out sometimes (again, one more than the other) but they load games pretty quickly. I tried matching the potentiometer resistance measurements form one of those on the CD-ROM2 & it was a total bust. Didn't work at all. Again, I'm not sure if this is related to caps... I'll post the resistance measurements from my TurboGrafx CD drives on here later this evening or tomorrow evening. It might at least be helpful to someone.

[yesimnathan]

I ended up going ahead & measuring my 3 CD drives this evening. Here are the results:

Best working TGCD

Code: [Select]

        AB      AC      BC
VR101   14.16K  7.62K   19.2K
VR102   8.91K   7.31K   10.69K
VR103   5.35K   16.63K  20K
VR104   3.71K   15.66K  19K
VR105   0       470     470

'Meh' working TGCD

Code: [Select]

        AB      AC      BC
VR101   11.02K  11.25K  19.5K
VR102   8.34K   9.16K   11.11K
VR103   5.10K   15.02K  18.2K
VR104   5.90K   14.62K  18.7K
VR105   0       441     441

Mostly non-working CD-ROM2

Code: [Select]

        AB      AC      BC
VR101   13.95K  8.08K   19.1K
VR102   10.44K  9.04K   11.95K
VR103   5.99K   15.53K  19.3K
VR104   6.07K   15.43K  19.4K
VR105   0       367     367

Tomorrow I'm going to experiment with adjusting the 'meh' working TGCD pots to be closer to the mostly working TGCD's pots. I'll also be ordering replacement caps for all 3 drives tomorrow. I'll be sure to report my findings!

[Keith Courage]

some drives may work better with other settings than others due to the lens maybe needing a slightly higher gain. Possibly from being older?

I've worked on many of these drives and I'd say maybe 50% of them have close to the same settings and work great whereas the other 50% end up needing certain things tweeked a bit to run well. I have not noticed any difference with newer capacitors with this issue.

[yesimnathan]

Literally just spent the last 3 or 4 hours trying to tweak the pots on my CD-ROM2 with no luck. This has been by far the most frustrating thing I have done in a long time. I'm basically at my wit's end here. I would be so gracious for any advice. I feel like I'm going mad working on this damn thing.

[Keith Courage]

what is the Drive doing? Does it still work but just not reading very accurately? if this is the case you are going to have to do it by process of elimination. meaning, try changing the settings on one of the potentiometers. If it doesn't make things better then put it back to the way it was and then try another one.

[yesimnathan]

what is the Drive doing? Does it still work but just not reading very accurately? if this is the case you are going to have to do it by process of elimination. meaning, try changing the settings on one of the potentiometers. If it doesn't make things better then put it back to the way it was and then try another one.

Finally made some progress the other day! I had originally replaced the laser with a laser from a Sony D-34 because I thought it was dead. I ended up putting the original laser back in & it became evident that it was not dead! Tuning the pots with this new laser has been much less challenging. I finally got real games playing (slow loading, but they worked). With some more tweaking, I had it playing the audio from burned CDs almost perfectly... but it completely refused to load a burned game. It didn't even seem like it was trying.

I accidentally pressed the "run" button with the disc tray open and I noticed that the console thought it was trying to load the game rather than telling me to close the lid... Keep in mind, I have used this exact interface unit, pc engine, power supply, etc... to play burned games with a different CD-ROM drive and it worked beautifully. Regardless, I swapped the interface unit for a spare that I have and it magically started playing burned games. I still have a few burned games that it doesn't like but burns on high quality media seem to be working very well now.

I'm starting to wonder if a lot of my frustration came from that interface unit that was apparently on its way out. Sometime this week I'll pop it open & see if I can figure out what's wrong with it. Thanks to everyone for the help! =)

[Keith Courage]

a while back I did come across a docking station that had the same problem. I did not try to fix it at the time and cannot remember what I did with it. Wondering if it's maybe a bad capacitor issue or not. the docking station in question would barely read regular discs and would not read CDR discs at all. However, if I move the CD drive over to another docking station it would work perfect.


so are you are not crazy in thinking that the docking station could have been the problem.