Cat + PC Engine Duo = Bad

Macross_VF1 · 12/12/2018, 05:04 PM

I've only just finished repairing my GT and I'm already looking into another console. This time it's one of my PC Engine Duo consoles. As the thread title suggests it had a close encounter with my cat many years ago where she managed to make the unit take a nasty fall. The Hucard slot still works fine but the CD player refuses to read disks. Could it be as simple as the reader being out of alignment or should I just replace the entire thing?

NightWolve · 12/12/2018, 08:11 PM

You'll have to provide more details on the exact problem if you want help to try something there before shipping it to one of our repair guys.

Do you get a boot screen, does the CD spin up ?? What error does the boot screen say ? The other things to check would be with the top open, but the sensor switch pressed down and booting in the dark to check if you see a red laser or not, and if the laser lens can move up/down to focus.

If laser is dead, will likely need replacement but if not, the 3 CD potentiometers will need adjustment. The laser is known to break with mishandling during shipping, happened to one of thesteve's customers.

Macross_VF1 · 12/13/2018, 04:00 PM

The console starts up to the normal Super CD ROM 2 system boot screen. However when I put in a disc and press the run button, the CD drive doesn't spin up and after a short while I get an error message 'Please set disc.' The laser itself does start up as I can see the red light from it but again, the drive doesn't spin so it doesn't seem to matter much. I can't tell whether the lens can focus or not.

dshadoff · 12/13/2018, 06:20 PM

Well, if the CD doesn't start spinning, you aren't seeing a laser-alignment problem (although I can't guarantee that you don't also have one).
I have seen some old systems fail to spin up, but I don't know enough about the electronics to know whether it could be explained by old/dead capacitors (probably could...).

Keith Courage · 12/14/2018, 03:31 AM

Of course it's worth trying to fix first. Your lens might even just be stuck. Those gears can jam up from time to time. Especially if dropped.

NightWolve · 12/14/2018, 03:59 PM

Quote from: Macross_VF1 on 12/13/2018, 04:00 PMThe console starts up to the normal Super CD ROM 2 system boot screen. However when I put in a disc and press the run button, the CD drive doesn't spin up and after a short while I get an error message 'Please set disc.' The laser itself does start up as I can see the red light from it but again, the drive doesn't spin so it doesn't seem to matter much. I can't tell whether the lens can focus or not.

Ah, so the spin motor won't start. *Maybe* there's a chance for you to fix it yourself since the laser shows life.

You need to see if the motor gets power, maybe the board area that supplies the power was hurt by the fall or the motor itself.

I'd disconnect the power cable to the motor, bring a 5VDC source from elsewhere to power it, see if it spins. If not, the motor broke, you'd have to see about replacement... Perhaps even before that, try to boot it and measure the voltage at red/black wires at the motor (you'll have to hold the switch down to make it believe the lid is closed).

I dunno if any of our repair tech heads ever mentioned that motor failing, they certainly have spare laser units to sell and sprockets that are also known to fail.

So, if the motor works with external power, you gotta find out what went wrong where it connects to for its normal power supply. A crack in the board area that supplies it perhaps, maybe a reflow of solder on the power connection pins that the cable connects to, that sort of thing with any luck! You'd have to fully free the motherboard, have a look underneath.

That's about it, seems you might have a shot, but if you give up, Keith is right here to ship it off to and let him try, good luck either way!

Oh, and if it hasn't been recapped, that should be part of the repair deal!

Macross_VF1 · 12/14/2018, 05:51 PM

While I haven't been able to power the disc motor separately yet, I did do something else. Since I have two Duos, and the other works as intended I figured I could swap the entire CD-drive unit between the consoles and eliminate a lot of troubleshooting in one go. If the 'Good' drive worked in the 'bad' Duo, I would immediately know that it's not something on the motherboard of the 'bad' Duo that's broken but instead the fault lies with the CD-drive. As it turns out it does, which makes the possibility of a broken spin motor far more likely.

However during the swapping I noticed a new problem, separate from the motor issue. The supposedly properly working CD-drive unit no longer plays any CD-audio tracks, no matter if it's mounted on the 'bad' or 'good' Duo. Any other audio works fine.

*Edit* Just read one of the repair guides and the sound issue is most likely capacitor related.

Macross_VF1 · 12/15/2018, 07:28 AM

Now I've tried power the motor and it spins as it should. However I've discovered that I do not seem to get more than 0.03V on the appropriate lines going to the motor and it also doesn't fluctuate when I try to run it. That might instead mean it's the BA6290A chip (IC108) that's faulty. When measuring the chip it does seem to receive the proper voltage but it doesn't output on the proper pins.

Just to be sure I also measured the lines going to the motor that moves the lens assembly (sled?) back and forth and that shows a marked difference despite being connected to the same chip. Higher voltage and fluctuates when it is supposed to receive commands.