"EADGBE" wrote in message
...
On Jul 25, 12:05 pm, "Arny Krueger" wrote:

Why bother fixing it?

I got it for free; it seems like a (fairly) nice CD player; just
curious about the sound.

I really don't know if I actually need the schematic. I'm pretty sure
it's a bad op-amp. The CD spindle motor won't activate, even though
the motor tests fine and so do the transistors responsible for
supplying the motor voltage.

It's just something to tinker with on a rainy afternoon, that's
all......


The fault you describe really is a bit "my car won't start even though
there's fuel in the tank. The engine cranks so the battery is fine. I
suspect it might be a bad radiator ... "

Sorry to put it that way, but very few problems with discs failing to spin
up, are ever anything to do with the motor's drive electronics, *unless* the
motor was faulty in the first place, in which case, occasionally, the motor
driver IC, where one is used, will be damaged. Where the drive is from a
four transistor bridge, it's very rare for them to have failed, bad motor or
not. The disc failing to spin up, when it's definitely *not* a motor
problem, is almost invariably because the system control is not releasing
the motor servo into a 'run' condition.

First checks should be :- If you move the laser down its track manually,
then open and close the drawer, does it then home ? Does the laser burn ?
Does it attempt focus ? With a disc in, does it achieve focus ? Does it
attempt to rotate the disc at all ? Are any pots in it way off centre (if
you don't know its pedigree, the phantom pot-twiddler may have been in there
before you ... ) d;~}

Collect a bit more info, then let us know, and we'll see if we can suggest
some more things you can look for.

Arfa