Original Pc Engine Duo Cd Laser Alignment Questions

[xybots]

Hi every one I was wondering if any one on this forum could help me please, I have my original Pc Engine Duo which I bought back when it 1st came out, But the laser isn't playing any original games anymore, I have ordered a new laser for it and awaiting it.

Before I recap it and do a RGB Mod on it, I just wanted to ask does any one know the following please.

The pot values of 101,102,103,104,105 for the Duo even though ive marked mine before fiddling I just want to know the values of them I can only see the values for the Duo-R are they the same ?

Also the pot value of the CD Laser pot the white one on the laser. and which test points I have to use or a picture of them please.

Also I am using a multimeter set to Ohms, obviously it plays hucards fine.

thank you in advance for your help and ill let you all know if I resurrect it.

 

[Keith Courage]

https://www.pcenginefans.com/forum/index.php?topic=8926.0

[xybots]

Thanks I have read this back to back, I just need to know if any one knows the test points for the Laser Pot and the values please

[Keith Courage]

Hopefully someone else can chime in. I do all my lens adjustments by ear. I've done so many of them I can tell by sound and loading times.

[xybots]

Thanks I hope someone on this forum can help me, when I put a game in the pc engine duo, and press start I’ve adjusted the Pots to let the cd spin but it spins really fast then I get “set disk” come up I hear the
laser head move up and down.

That’s why I need the measurements so I can use a multimeter.

Thanks

[Keith Courage]

If it spins up really really fast. Generally adjusting the V102 will fix it. If it doesn't, it means the lens is bad. 

[xybots]

Hi All

Ive got my new laser and replaced it, but original games still won't load up, I think the pots are messed up, I tried the laser on a different Duo and it worked and loaded straight away.

can any one help me further please where to go next.

thanks

[Keith Courage]

I would set the adjustments to same as the other DUO you have that works as a starting point. Then you can adjust as needed from there. There is one larger notch in each of the potentiometers that you can look at for reference.

[xybots]

I adjusted the pots back to the duo I have that works and I still can't get it to work, I tested the laser again in my duo that works and the laser is fine, any other suggestions would be grateful.

I was wondering if a cheap Oscilloscope would help me, if so what would I look for Mhz etc, I've seen on eBay these ones would they work

https://www.ebay.co.uk/itm/Oscilloscope-Assembled-Sample-Rate-With-Indication-Automatic-Pocket-Digital/264746211551?hash=item3da41a98df:g:Cd0AAOSwhl1e0Asn

any help and pointers are great

thanks

[Keith Courage]

So before the replacement lens or adjusting, it wasn't reading games anymore? Has the system been recapped yet? Bad capacitors can also cause CD reading issues, not just sound problems.

[xybots]

No this hasn't played cd games for years, I've ordered caps to try and recap the machine, but thought a new laser would do the trick, do you not recommend a Oscilloscope to help me along the way before i try and recap this duo.

thanks

[Keith Courage]

I would just recap it first. 85% of the time, caps are the cause of CD reading issues in DUOs. Most people just think lens first because that's usually the case with other common game consoles.

[Dylanward]

Hello,
Here’s a list to do first before adjusting pots.
1. Clean system
2. Put new capacitors on the system all of them.
3. Clean rails, gears and the inside of the laser holes then regrease with white lithium grease.
4. Recap your PSU.
5. Test system.
6. Check for damaged traces and components.

If audio is fully working on hucard son both speakers. Try CD game and audio CD.
If it’s not spinning, playing audio, skipping etc. Then refer to the pot adjustment guide here. If you want a better more professional fix. Get a oscilloscope and I can tell you how to set it up. After that you would want to be gentle and play with a combination of the first three pots on the list to guide yourself to be able to play all discs.