PC ENGINE DUO "PLEASE SET DISC!"

[elartur77]

Hello everyone.

Hope someone can help..

I got this DUO some months ago no working, I replaced all the caps, cleaned the laser and then worked like new.. I could play anything I threw at it original and backups, I used it for around a couple of months working great, but then I just leave it for a month or so, and yesterday that I wanted to play a little more it just dont wanted to read anything!!.

I just got the mesage "PLEASE SET DISC!" with every disk I tried, orginals, backups, music CD etc..

It start to spin at normal speed, nothing seems wrong at all, no weird noises, but then after a few seconds trying to read it just stop and appears "PLEASE SET DISC!"

The HUCARD part works great! but the CD part dont..


I open the thing and tried all this:

-Clean the lens.

-Reseat the laser and the harnes cables.

-Try another harnes from other unit.

-Change the laser with a brand new one.

-Check continuity on the recently changed caps and reflow the solder.

-Messed with the pots but nothing helped.

-Checked VCO with a multimeter and gaves me 4.33 Mhz when starts to spin, but still stops and "PLEASE SET DISC!"

So I really dont know what else to do, Im lost here, the system didnt fell off or got wet , I put it in a well ventilated area..

The only thing I can think of is that the board is a little messy with the solder flux i used, maybe a via got cloged?

I dont know, please could someone can give me some advise?

Thanks

[Keith Courage]

Something to try which might sound weird, but I come across maybe 1 duo a year with an issue where it has to be used for 3-4 minutes before a disc will start working sometimes on a cold start. I would assume this is caused by a bad trace or connection on the board but I haven't been able to figure out where.

Anyways, just for the sake of trying it, Just hit run to start up a CD over and over again for about 5 minutes and see if the DUO magically starts reading discs again.

[elartur77]

Something to try which might sound weird, but I come across maybe 1 duo a year with an issue where it has to be used for 3-4 minutes before a disc will start working sometimes on a cold start. I would assume this is caused by a bad trace or connection on the board but I haven't been able to figure out where.

Anyways, just for the sake of trying it, Just hit run to start up a CD over and over again for about 5 minutes and see if the DUO magically starts reading discs again.

Thanks Keith for your reply, I'm going to try your recommendations..

Just to add, I did some other tests:

-I washed and cleaned the whole board inside a plastic container with IPA and a toothbrush (now the board looks like new)

-I replaced some caps that I knew were low quality.

-I kept playing with the pots.

-Tested with diferent power supply (original and a generic one)

But after all this, it still shows "PLEASE SET DISK"

And then I was lucky enough to get another DUO which worked great and I did some tests, the pickups on both lasers worked great on the new DUO, and both lasers didn't work on the old DUO, only "PLEASE SET DISK" showed up on both..

So the problem is definitely the old board.

But I can't detect anything wrong with the board by eye, no corroded vias, leaking caps, no dark areas, etc. I checked all around the laser and under the board but nothing, I don't know where to start..

Or maybe is power related that why I tested with diferent power suply and the voltages of the regulators was 5v output..

Which part of the board should I check that could give me "PLEASE SET DISK" if anything is wrong?

Thanks

[Keith Courage]

"Please set disc" can be caused by a lot of different things. A bad lens, bad lens cable, poorly adjusted potentiometers, a bad potentiometer, a stuck gear, a weak lens motor, a bad trace, bad/shorted via hole connection, faulty chip on the board, etc.....

So if your positive the Lens is fine and the lens adjustment potentiometers are fine, then I would start by looking at the Via hole connections just to the right of the CD loading light. The 47UF caps typically leak there and can short the vias.

[elartur77]

Thanks Keith.

I try everything but still got "PLEASE SET DISC" 

Ill leave it for now Im tired of this board.. and retake it later..


Ill update if I found a solution..

Thank you very much for the advice ...