Troubleshooting TG-CD player

[kid_rondeau]

Hey all,
I still have my original Turbo CD-ROM add-on, even though it hasn't worked since 2001. I swore to myself that one day, when I was a little better at electronics, I would attempt to troubleshoot the device to see if I could repair it.
Its chief problem? Pressing "Run" on the startup screen caused no response from the CD player. None whatsoever.

Well, this morning I took the old girl apart and was actually able to remove the CD motor and the laser/leadscrew motor!
Using a 9-Volt battery, I checked both motors and they both work perfectly.
It was good to find out that neither motor had burned out, but it was a little disappointing because I REALLY wanted that to be the problem!

So now all I've done is eliminated the motors as culprits. I still have more analysis to do, but I'm a little lost as to where to start.


I'm posting this for two reasons: the first is so anyone who is in my predicament may benefit from my results (or lack thereof). The second is in case anyone who understands the circuitry may be able to guide or advise me.


In any case, most people on these forums tend to be Duo owners; I haven't seen much interest in the TG-CD hardware.


Thanks for listening!

[nat]

Check the "lock" switch on the bottom of the unit and also the lock switch on the side of the unit. Make sure both are in "lock" position. If they aren't, they won't pass power to the CD drive. If they are locked, the switch itself might be bad.

[kid_rondeau]

Hey Nat,
thanks for the advice!
I wasn't clear enough in my original post, I guess...a more accurate description of the problem is this:
When I press Run, the "PC" appears on the CD-ROM unit, but the leadscrew/laser motor never turns on to seek home. It just sits there saying "PC".
When I try to use the CD-ROM as an audio CD player, the display reads "0" and no motor noises can be heard.

But I have made some progress!
I wanted to reassemble my CD-ROM unit to make sure I could get it back together again with no parts leftover (an underappreciated skill!), and just in case my tinkering fixed the problem.

I took my 9V battery and tried the CD motor...it spun freely. But then I tried the laser motor again:
it worked, but intermittently. I removed it from the assembly and applied power again. It worked well enough on its own, but when I put it back in, it would bind and couldn't turn the various gears to move the laser!

Upon closer visual inspection, I noticed two broken teeth on one of the gears!

I manually rotated said gear past the broken teeth and reapplied 9v to the motor. This time, the motor spun until I reached the broken spot on the gear again. And once again, it bound up!

From here I decided to keep turning the gears manually, and I actually ended up stripping ALL THE TEETH off that one offending gear. Arrgh!! 

Still, without a real interim strategy, I put everything back together the way it was. The only difference was the toothless drive gear.


So, after I reassembly, I put in an audio CD to test the device. This time, when I pressed "Play", the display still read "0", but I could actually hear the laser motor spinning freely away, with nothing to mesh with.

My assumption is this (and anyone with knowledgeable input is welcome to advise):
The reason my CD-ROM was unresponsive in the first place was because the laser motor was stuck on the stripped gear.
I further assume that the CD-ROM's programming has somekind of instruction set where it basically says: "Step 1: Laser Home; Step 2: Spin CD motor to 300RPM..." etc. And without being able to move the laser, the CD motor can't spin, and the game can never load.


I'm going to start looking for a replacement laser/leadscrew/motor assembly, because I don't see any way to replace that one gear. But I will update if I find anything useful.

[nat]

That's too bad. I've never taken apart a TG-CD drive, but it seems like there should be a way to replace just the gear.