Turbo Duo game CD audio stops playing

[cr4zymanz0r]

Ok, I just got a Turbo Duo in today that I knew had issues with game discs but I thought I'd touch base here for suggestions before blindly playing with the CD-ROM pots.

Hucards work fine, and music CDs boot up and play all tracks fine without any apparent struggling. The capacitors have not been replaced, but I do have some replacement ones on the way. However, the stock ones in it don't look awful currently.

So, when I attempt to load a game disc it spins up the disc and sounds pretty normal initially. After a few seconds the busy light blinks, then there's a mild "click" noise (either from the laser re-seeking or the spindle motor restarting. not sure which). After the click it goes through the initial seeking/loading, busy light blinks again, click happens again, and this cycle repeats continually until I stop it. It's sitting at the bios with "just a moment..." all while this is happening.

I recorded a video to show what it's doing with the case off and a magnet on the game disc to hold it in place. Please excuse the background noise.

(the initial click noise when the disc starts spinning is me turning on the flashlight).

I'm also using the original power brick and verified it's putting out enough voltage with a multimeter.

[turbokon]

First, you should replace all the capacitors.  Secondly, try using the stock magnetic piece that's sitting on top of the spindle.  Looks like you're using something from another hardware that might not be as balances as the stock's.

[cr4zymanz0r]

The results are the same when it's all put together or when disassembled. I just did the video disassembled so people could see the laser moving.

The caps will probably be in later this week. I'll probably go ahead and start removing the old ones soon.

[cr4zymanz0r]

Ok, got the new capacitors in today and replaced all the old ones after removing them and cleaning up the board. Now the Duo is booting CD games, but there are random issues with CD audio in-game.

Some games seem fine, but in Lords of Thunder sometimes the CD audio never starts playing and occasionally it just stops playing until the music changes. The CD drive seems to be making quiet but high pitched noise when Lords of Thunder is being played (I hear it some in other games, but not near as much). The disc is flawless and works fine on a Duo-R.

I assume I need to adjust one of the potentiometers on the board, but which one would be mostly likely to correspond to this cd audio issue?

[Keith Courage]

sounds like you need to either regrease the lens rails for the CD Drive or make some minor potentiometer adjustments.

[cr4zymanz0r]

I re-greased the lens rails and that didn't change anything.

Next I tried changing the 102 potentiometer, but that didn't change much other than making it not load games if i turned it too far.

Afterwards I tried the 103 potentiometer and this gave the best results. Turning it counter-clockwise only made things worse. Turning it clockwise did improve things. I turned it until the high pitched noise from the laser I mentioned earlier went away.
CD audio in games was seemingly working fine then, but when trying the last track of a music CD there were small issues. I kept slowly turning it counter-clockwise back towards it's original position and eventually found a spot where CD game audio is apparently fine and so was the last track of music CDs.
However the high pitched laser noise is still present in that position. It's not really audible over the game audio. Oddly it only seems to make the noise in Super CD games (particularly Lords of Thunder). I don't know if that's normal or not but at least everything is playing fine in it so far.

[Keith Courage]

If it is messing up near the end of the CD tracks then a minor adjustment of the V101 or V104 would fix the problem.

[Xenogears]

...and if tweaking the Pots does not fix it, then get a new laser. That was the reason for my issue when the sound suddenly stopped .

[wolfman]

You shouldn´t hear the laser at all, only a brief moment when it is "zeroing" in onto the track the moment it is moving to the position. Then there should be an intermittent, shivering low noise indicating a balancing movement. Otherwise the drive should be silent during play.

If you have a high-pitched noise, then your tracking/focus adjustment is wrong. From my experience both should be almost in identical position. These are pots 103 and 104. If they are adjusted correctly, you the noise is gone, so If you move them, move them both into the same position, and from that slowly until the noise is gone.

[override]

I will have to look around but at some point I had the correct settings for the pots, I gathered that info when I used to replace the laser and the adjustments I found seemed to work best all around. Although I would guess to say that your laser is most likely weak. Good news is the lasers can be had for about $30 (if I remember right).

Next thing I know is two chips that I found started becoming a trouble area on some consoles the one for Redbook audio would start to get extremely hot within seconds of spinning up the CD it was the BA6290A chip. Replace that and CD audio always seemed to come back to life. The other chip was the OKI M5205 but honestly I can't remember why I used to replace that chip. I wanna say it had to do with up-scaling the cd audio.