Beginning guide for fixing Duo not playing cds issue!

[override]

Hello,

Recently bludgeon sent me a Duo that needed a sound fix, I did a full cap replacement and to my demise while testing (Lords of Thunder) the sound made a horrible scratching noise and died (ALL OF IT)....Thats right everybit of sound died, so I proceeded to check the laser with out a cd, when it was dipping down to focus it would dip crooked so that was my suspect....I also notice tho one of the chips was getting really really hot, to a point that I touched it and it burnt my finger (ouch!). So now I had two suspects....Needless to say I popped my Duo-R apart and swapped the laser out with mine. Tested and it worked great! I also recieved soviets board from here the other day with his confusing cd issues and was able to fix his system in a matter of 30 minutes or so......So now that you know the story, I will proceed to the guide portion.

Issues:

Not playing CD's
Sound is staticy/CD sound dies in the middle of game
Laser making a whirring/squealing noise

Im sure there are more, feel free to comment....

Testing:

Pop the top off your duo and grab a piece of electric tape and tape the CD door switch down. Start up the duo and without a CD press run. Laser should dip down or pan up to try and focus for a CD, check and make sure the Laser is doing this motion straight up and down. If nothing happens what so ever check to make sure the sled gear, motor gear or motor to sled gear are intact and in good condition. On the motor gear I have seen before that the gear itself has come loose and the motor spindle spins freely in the gear so check that aswell.

Also check to make sure the two BA6290A chips are not getting to hot. These chips will get hot but excessive heat (say from testing or trying to get the CD player to work after its died) will A- Be hot to touch almost burning your finger or B- Over time have gotten so hot the chip itself burned up. The chips will heat up pretty fast, Id say about 30 seconds to a minute they will be to hot to touch.
Either way if it's the laser or a dead chip one will get excessively hot, if not both.
If you think the laser is bad and have a spare laser then swap them out and test it with a known working laser, if not then you can order one here.

If you suspect the chip(s) are bad you can order them here.

I will come back with a more comprehensive guide with pictures and more in depth explaining on step by step how to do either of the two things above. I also plan on pinning out the chips to what capacitors or anything else is run with them and the CD player aswell! I will also provide pics of this!

For now I hope this helps people having this issue!
I am always open for repairs and mods, lemme know and we can talk about what needs to be done, send me the system and Ill fix it for ya!
Thanks and hope this helps!
Anyone who has anything to add feel free!

[kattare]

Hey, nice.  We really need a wiki or something to collaborate on these repair guides!

https://www.pcengine-fx.com/forums/index.php?topic=7115.0

[Sensato Black Lion]

Hi, I have a Duo with audio problems. I replaced 39 caps and the problem is still there. I swapped the laser and the audio is alright now. So it seems I a faulty laser on this Duo.

Before replacing it, I'm wondering if there isn't some adjustments which can be made, like the strength , tracking and focus of the beam? I'm going to do a few tests with that Duo today and post back the results.

edit: Ok, I just went through the Laser Power Issues and Pot adjusment topics... didn't realise they existed before posting.

[override]

Hi, I have a Duo with audio problems. I replaced 39 caps and the problem is still there. I swapped the laser and the audio is alright now. So it seems I a faulty laser on this Duo.

Before replacing it, I'm wondering if there isn't some adjustments which can be made, like the strength , tracking and focus of the beam? I'm going to do a few tests with that Duo today and post back the results.

edit: Ok, I just went through the Laser Power Issues and Pot adjusment topics... didn't realise they existed before posting.

I just replaced the laser in bludgeons system which was one of them that helped me kinda start this guide, I adjusted the power of the laser with no known changes in reading the disc other than when I took to much power away it cause the laser to be off track. I have not messed with the post any but honestly I dont believe that replaceing the laser with an exact replacement would cause you to need to adjust anything, the best you could do is check your pots against a known working system and make sure yours are in that range. If not tweak them a bit and see what happens. Be sure to mark then where they are set at before you start adjusting.

[kattare]

Just wanted to add to your experience override, I recently did a laser replacement.  Unit here: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=330354072462 The unit after the laser swap would not even spin the discs.  I thought I got a bad laser at first.  I tuned the focus offset though and eventually got the disc spinning.  15 minutes and a bunch more tweaks later, I got it to reliably read every CD-R I threw at it.  It's like a Duo possessed with the spirit of a Duo-R.   

And now you know why I'm charging so much for it there on ebay, it really is a rare unit... I have 6 other duo's here in my shop and that one is the best of the bunch.  Though... what I'm asking for it seems to be a fraction of what some of the other sellers ask.  heh.  I wish I could sell the things for $500 - $1000!

Anyhow, just wanted to throw that out there.  There's a lot of variety in how these things come out of the factory (do they even all come from the same manufacturer?  I've seen like 3 different packages with different company logos, etc.) ... I think that's why the pots were necessary on the board in the first place.  The folks in the factory must have had to hook into each unit and tune 'em before boxing them up.

Cheers.