After a bit of hair-pulling, I was able to remove the E-clip holding the
assembly. Relubed it w/ white lithium grease, but it didn't make much of
a difference.

Regarding the motor, yes it uses 20v (outlined in the service manual) &
has a rubber plug on the bottom, but I can't figure out how to get it
out. W/ a voltmeter across the motor, & running w/ no load, I get a
steady 21.2V. Would the voltage vary if the motor had speed issues? It
does do so, under load, in time w/ the audio fluctuations. But I can
also make the voltage drop under no load by pressing down on the pulley.

Another possible problem is that the center of my capstan is quite worn
smooth. A website (8trackavenue.com) suggests "roughing" it a bit w/ a
scouring pad inserted into the front of an empty cartridge. Gonna give
that a try, too.

Strangely, the deck will play w/o any trouble if I turn it over sideways.

On 10/12/2015 7:54 AM, Bruce Esquibel wrote:
wrote:

Lubrication issues? Sounds like the capstan might be wobbling in the bushings.
If the belt turned to crud you can be certain the lubes are bad too.
Sony is notorious for using lousy lubricants even in $100,000 broadcast
machines.

Not sure about this but figured I'd toss it out.

Didn't most of the 8-track players use a self-regulated dc motor?

I don't remember what the exact name was but they were 12v dc motors that
had a built in regulator/speed control and you normally applied 14~20 volts
to them.

Usually on the flat side (opposite the shaft out side) there was a label
covering up a hole for a pot, to set the speed.

Although after all these years it probably is a bering/lube problem but the
fact that it worked a week or so before this symptom cropped up, seems a
little strange.

Kind of have a feeling it's something with the regulator circuit board
inside the motor, which even back in the day means the whole motor needs to
be replaced. Seemed like trying to take them apart pretty much destroyed
them.

Just a thought.

-bruce