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NEC TG-16/TE/TurboDuo => TG/PCE Repair/Mod Discussion => Topic started by: stridervm on November 26, 2025, 07:50:45 AM
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Hello noob here about basically everything about PC Engine.
Anyway I got this PC Engine Duo in a Japanese Auction for about $65. Hoping I would be able to be lucky to make it 100% working on burned CD games the same way for my PC Engine with IFU-30 CD-ROM.
I started blindly changing the dials (Bad idea I know) and somehow I got it partially working on some on the burned CD's I made.
However, the wierd thing is that the console needs to be crooked a little to the left in order to read the CD.
https://www.youtube.com/watch?v=T40VtPfZ8Vw
It cannot read any CD when the console is leveled to the table.
https://www.youtube.com/watch?v=-0P5JAoBfws
I wonder what could be causing this? Any suggestions?
After that crooked angle loading is solved when I will try to actually adjust the potentiometers again.
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I'm not an expert on this hardware; I'm just starting to research and learn about it. I don't know if you're experiencing the same issue as with the PlayStation 1 drives. There were usually two problems: a misaligned lens and discs that wobbled too much while spinning. On the CD-ROM2, I believe the VR102 potentiometer is responsible for correcting the focus height between the lens and the disc. I don't know if adjusting it will have any effect on your console. I'm sorry I can't be of more help; perhaps what I'm saying is nonsense.
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Any suggestion is better than going blind. I'll try to adjust it in the evening after work.
Anyway a question about adjusting the potentiometers. In the image from this site.
https://www.retrosix.wiki/laser-tuning-pc-engine-duo
(https://images.archbee.com/9EnOacbhz7Zqgrsars4GT/unPgKYUm2P374qs5xSWs3_vr102.jpg?format=webp&width=800)
I assume this is set near the middle. Just turned a little bit counter-clockwise.
What should be a sensible range of adjustment? What I have been doing when adjusting is from the "middle" , turn the dial 5 degrees counterclockwise, then power on. If nothing changes, do it again, up to 45 degrees. Then reset it to the middle. Then go clockwise then.
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Has the system had it's capacitors changed? This is a big cause for CD reading problems.
Yes, potentiometers can be adjusted to help read CDR discs, although I should mention that I come across probabaly 1 or 2 DUOs a year, that no matter what is done with adjustments or changing out lenses, that the drive just refuses to read CDR discs.
Also, some DUOs only work good with certain types of CDR media for whatever reason. Some DUOs I've worked on might only work good with the cheaper types(light green bottom) and some DUOs require the slightly more costly AZO dye discs(more bluish green bottom discs).
I do all of my lens adjustments with live tesing and making adjustments by ear. So, I can really make any suggestions by seeing pictures of the potentiomers or volt readings from them.
Usually the V102, V103, or V104 may need slight adjustments one way or the other to help with CDR disc usage.
V101 is lens position. So this one usually only needs adjustment if the audio has random audio drops every now and again. V102 also can help with random audio drops.
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I'll try to post pictures of the whole motherboard to show if it's capacitors have been changed (Most likely not). Also the potentiometers as well.
Big issue is I do not have the skills to have the capacitors changed nor know someone who can change it in at least 100 miles. I also have no skills to read the potentiometer voltages as well.
So there can be a case, that no matter how much you adjust it, certain PC Engine Duos will not be able to read CD-Rs. But what happened with mine is that is can read some CD-R. But not all. At least with the current adjustments.
Anyway, have you experienced a similar issue to my console where, to read (some) CD-Rs I needed to run the system in an angled position. Any suggestions?
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That sounds like lens adjustments needed or a worn laser. This is the case for a Black Tg16 and white PCE CD drive when they only work when turned on their side.
Have you been able to test any other CDR media or do you only have one type on hand?
I test like 4 different brands for my cutomers when they send me DUOs for servicing. That way they will know which one works best with their particular DUO. Otherwise, I might get a random message saying, "Hey my DUO won't read CDRs". "You didn't fix it right". This way they will know what CDR works best. So that won't ever happen.