DIYbanter - View Single Post - Sony MDP-500 Laserdisc shutdown problem.

wrote:

My laserdisc has recently stopped working. It used to be fine but now
it will not power-on completely.

When I hit the power button on the front or on the remote, it turns on
and turns off almost immediately. I hear a click when it turns on and
another click when it shuts down, maybe 1-1.5 seconds later.

I also took the cover off and I can see the laser move out about 1/4"
and then back again in concert with the clicks.

This model apparently has another problem with the loading gears on the
right side of the player, but this doesn't seem to be the cause of the
power-cycling problem. The gears look like they are working fine, and I
can move them by hand. Also, the gear problem is supposed to cause a
shutdown about 30 seconds after powering on, where this player turns
off almost immediately.

I think the player is either responding to a problem and shutting down,
or has a power supply problem.
Maybe the unit is detecting a problem with the laser or the sled
mechanism ( the system that slides the laser from the inner to the outer
edge of the disc )
There could be a problem with a malfunctioning sensor - a drawer sensor
or a laser "home" sensor.
One thing you might try is to move the laser to the outer edge by hand,
with the power off, then turn the power on and see if it reurns to home.
On some players it may be easy to move, and on some it can be difficult,
so DO NOT FORCE IT!!! or you will certainly break gears.
If your unit has belts, one of them could simply be slipping, or broken.
Or maybe some of the gears or some part of he mechanism is jamming
because the grease has dried up. The best solution for that is to clean
off all the old grease with Q-Tips moistened with WD-40, then clean off
the WD-40 with dry Q-Tips, then apply fresh lithium grease such as
Lubriplate. Work with the power disconnected, Don't drip any WD-40, and
apply enough grease to coat gear teeth that will mesh with other gears,
but don't overdo it. Too much grease may fly off the gears when they
spin, coating surfaces that they should not. Or too much grease may
attract dust, dirt, pet hair, etc. causing all kinds of trouble.

If all that fails, I would reccomend you star troubleshooting by testing
that all mechanical parts move through their full range of motion (power
off) by hand. Use a DMM to confirm operation of all sensors.
If power supply has voltages marked, confirm that it's functioning
correctly. If it's not, troubleshoot power supply failure.
If you have no luck after all that, it's time to buy the service manual
if it's available.