On Dec 7, 1:59*pm, wrote:
Hi,
* * * I am a service technician for many years. *This Aiwa Z-L500 stereo is
my own.

* * * From time to time, I can not eject a cassette. *Both units (dual
cassette) have this issue. *I replaced the belts, but that did not solve this
problem.

* * * More often this occurs when you use FF or RW and the tape
reaches the end. *A solenoid (part of auto stop system) activates (click,
click, click), but the head assembly does not go down (disengage). *It remains
up in the cassette.

This is almost certainly the belts still. You probably need some which
are a bit shorter or a bit thicker.
Did you clean the motor pulley and capstan flywheel surfaces with
alcohol before fitting the new ones? This is essential to remove old
deposits and grease which cause slippage under load.

It could also be that the cam and its follower arm /associated
sliders, racks etc. have old grease on which has hardened and is
causing things to bind. Only cure is a full strip down, clean, and
regrease. However, this is not likely in a cassette deck like this.

In particular problem cases, I have found that roughening up the
plastic on the grooves where the belts go helps give it that bit more
grip.

HTH
regards
B.