PC Engine DUO - CD-Sound Issue

[Xenogears]

Hello out there, I am in need of help. My PC-Engine Duo looses CD-Audio during play. What I already did:

- renew the laser
- recap all Electrolytic Caps
- renew the Pots
- adjusted the pots in serveral ways

CD-Rom  and Super CD-ROM start playing. If I use an Audio Disc there is NO issue. Every Track is played smooth from beginning to the end.

If I start a game, the CD-Sound collapses. What I found out - it happens, when the CD-ROM goes in somewhat, seeming to be a standby mode. The CD "idles" and when that happens, the Sound is gone until a next Level starts.

I tried to adjust the Pots a Little more, but things are not getting better.

Does anyone have an Idea ?

Update - I managed to force the issue. If I measure Voltage/ground on the second Pin from the right on P7 (the white plug on the far bottom-right side) the CD does this issue... Voltmeter reads 2.02 Volts +

[toymachine78]

My TG16 CD does this sometimes too.

[turbokon]

You just need to keep adjusting every pots until you find that perfect spots.  There is no easy to do this except with time and patience.

[Xenogears]

Well, I measured the pots and adjusted them, compared the laser Pot to my second perfectly working duo - Laser set to 0,784 kOhm, pots Settings were copied and pasted and then optimized a Little bit...

[Xenogears]

I tweaked, tiwstet and measured every Position, I could imagine. What the System does: it reads Audio-CDs perfectly and also plays WINDS OF THUNDER. The Duo refuses to Play other games. My Suggestion - it´s not the laser, as it plays CD and also Winds of thunder. Are there any other Options, I could check ?

Sad . . . Dan

[NightWolve]

PM a member here called 'thesteve' with your thread. I was gonna bring up the issue of the relubrication of the slider poles, dunno if you did that when you installed the laser. That solves the problem when you're playing a game and the redbook audio plays for a while, skips, and stops until you cause a scene change to load a new track. The laser needs to be agile and if its got 20 year-old mostly dried-up lithium grease leftover, it's not gonna work well. I added motor oil to that drive motor as well when I did mine. So, this might be an FYI for toymachine's problem, why I mention it. Anyway, your problem sounds more like those pots aren't quite right. :/

[thesteve]

The CD chipset runs 2 modes
In audio mode (music cd) it has error correct and recovery
In data mode (game) every read error puts the drive in idle waiting for next command
Your system is having read errors, which is either snags in the sled movement or pot adjustments

[Xenogears]

Pots are set as follows:

Laser: 0,78 kOhm
VR 101 - 6,73 kOhm
VR 102 - 8,09 kOhm
VR 103 - 14,5 kOhm
VR 104 - 16,58 kOhm
VR 105 -   297,8 Ohm

Thanks to thesteve - this is a very useful hint. Actually I am not at home, have to wait for the weekend - my Idea is maybe the sled. I twisted the Data-Cable twice, so it´ s forced to stay down, when a CD runs without cover. So it might be, that the cable works as a pullback-spring... and if it´s ony a few Nanometers, this would be enough, wouldn´t it ?

So please stay tuned on friday night - I will Report.

@ thesteve - is there a chip-leg that could be pulled high / low to toggle between CD / Data-Mode just for testing ?

[Xenogears]

There was a Problem with the lasers. They all were malfunction. I ordered new ones that where covered in Brown industrial looking boxes. The new broken ones were delivered in light blue and yellow thin boxes. I will never buy those lasers again.

Pots are fine. Now everything is read correctly...