PC-Engine Duo-R: Redbook Audio Problems

[EmperorIng]

I recently purchased a PC-Engine Duo-R from doujindance. According to the description that includes a region-mod, RGB mod, and a new CD lens.

For the most part the machine works well. HuCards are not a problem. There are some hitches with the CD reader:

1) a few games have had occasional lockups and freezes at the startup screen ("Please Set Disc!")

2) this is more random than not (in terms of what games it effects), but redbook audio will occasionally start stuttering, popping, or crackling, often cutting out entirely, leaving only the chip sound effects. I originally thought this problem was localized to my Valis III disc, which is a little scuffed (nothing terrible), but it has happened on my better-kept CDs as well.

As a note, I soft-reset the system before removing the disc, and I do not leave the system plugged in. I use a PS2 slim AC adaptor. Usually, but not always, leaving the system off for a while and coming back to it allows it to play audio without issues, but they seem to creep back as the system is used more and more. Also, chiptune sounds are not affected.

I was wondering if anyone here has experience with Duo-Rs and their potential problems. One person on PCEngineFX has suggested that it might be an issue with the lens needing a re-setting, or a regreasing. Has anyone done this before, and is this a fairly painless procedure?

I have been contemplating sending the machine in to a specialist (turbografxfan on ebay), in order to make sure that the Duo-R is completely fixed and I can enjoy the thing without any more headaches in the foreseeable future.

[mickcris]

It does sound like something with the laser physically out of alignment or needing adjustment probably. I would take the top off of the console and see if there is anything obvious. Something could have been knocked loose or misaligned during shipping.

Also, FYI turbografxfan on ebay is the same person who was replying in your thread over at Pcenginefx.

[EmperorIng]

Yeah, I reached out to him on the forums. Right now I ordered one of those Torx T10 screwdrivers (my pappy's tool shed has none of them gaming tools), so I will try opening up the machine later this week. I hope it's something so obvious that even a dummy like me can fix it!

[niall]

Doujindance has a YouTube video up showing some pots that can be adjusted - not sure if it's at all related to CD-Audio but worth checking them as well in case they are: https://www.youtube.com/watch?v=tNUw4PWy8Q8

[EmperorIng]

I did open up the Duo-R, just to see if there was anything obvious, but I couldn't tell; nothing looked knocked out of place or dirty.



I admit that I was a bit too chicken at the moment to start messing around with potentiometer adjustments, especially when I don't know the machine hardware all that well. I had a few more problems today with other CD games, namely Valis I and Shubibiman 3 with audio skipping and game freezing in the former, and music cutting out in the latter. I'm starting to think that whatever is up with the system might be a bit out of my hands.

[mickcris]

yeah. everyting looks ok there as far as i can tell. you may have to send it to turbografxfan to do a pot adjustment.

[viletim]

There's lots of things that can go wrong in a CD drive assembly. I suggest you first clean the objective lens if you haven't already. Use a cotton tip and some alcohol based solvent (metho, etc). Use the dry end of the tip to clean away any residue left from the solvent.

I recommend against playing with the pots. It's not a user adjustment. The reason they exist is to compensate for variation in laser diodes. If the characteristics of the diode has changed enough that it requires the pots to be changed then the laser diode is near the end of its life and should be replaced anyway. In the best case you'll prolong its life for a few more months.

You're not supposed to make the adjustment blindly. The procedure is to connect an oscilloscope up to the bit stream test point on the board and check the eye pattern for data integrity. You can see whether what you're adjusting is making an improvement and whether the data integrity of the result is acceptable.