Author Topic: PC Engine Duo Pots/Laser Issues  (Read 587 times)

3do_kid

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PC Engine Duo Pots/Laser Issues
« on: December 22, 2020, 11:16:15 AM »
I have a PC Engine DUO. It has been RGB modded and I recently performed the jailbars fix by replacing C923 and C909 with a 4.7 uF capacitor from Console5. The install went well and there are no more jailbars which is great. Unfortunately, after the install, my system had issues reading CDs (original Super Cdrom2 games not CDRs). I tried installing a new laser but the issue remained. I used this topic, https://www.pcenginefans.com/forum/index.php?topic=8926.0, to attempt to tune POTS. I had it working at one point but of course I messed with it again to get CDRs to read and now I can't get anything to read correctly. Currently the game loads bunch the CD music has a lot of skipping and distortion.

I've been trying to set my POTS values to the following as per the sticky thread:

vr101:AB=12.33 AC=10.65 BC=19.55
vr102:AB=7.89 AC=8.11 BC=11.28
vr103:AB=7.25 AC=7.14 BC=18.46
vr105:AB=0.38 AC=0.00 BC=0.38 (0.30 for this one as per later thread comments)


But I'm not sure what leads are what when reading AB, AC and BC using a voltameter. Can someone clear this up for me? Much appreciated

Keith Courage

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Re: PC Engine Duo Pots/Laser Issues
« Reply #1 on: December 23, 2020, 10:20:50 AM »
Was the console working fine with CDs before the work? Also, has the system ever had a full system capacitor change yet? 85% of the time CD read issues are caused by bad caps, not the lens.

3do_kid

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Re: PC Engine Duo Pots/Laser Issues
« Reply #2 on: December 23, 2020, 03:16:55 PM »
Yes it was working prior to my jailbarfix. The through hole caps have been replaced but not the surfaces mounted caps. I will replace these eventually but I did have it working with the new lense until I messed with it.

3do_kid

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Re: PC Engine Duo Pots/Laser Issues
« Reply #3 on: December 27, 2020, 02:45:41 PM »
I got the audio working better but opening cut scenes for cd games are still problematic. If anyone could provide their pots reading with which pins map to what reading that would be a big help.