Help needed with CD focus adjustment

[Mark]

I'm trying to fix a Aiwa micro system that won't recognise a disc.

Going by the repair faq I'm monitoring the focus bias test point but I
get a fixed 2.4v signal irrespective of how I adjust the focus offset
potentiometer.

By adjusting the potentiometer I can get the disc to spin up and
provide a TOC, so it must be having some effect.

Just wondering why I get no change on the focus offset test point?

Thanks

 

[Andy Cuffe]

I'm trying to fix a Aiwa micro system that won't recognise a disc.

Going by the repair faq I'm monitoring the focus bias test point but I
get a fixed 2.4v signal irrespective of how I adjust the focus offset
potentiometer.

By adjusting the potentiometer I can get the disc to spin up and
provide a TOC, so it must be having some effect.

Just wondering why I get no change on the focus offset test point?

Thanks

The Sony optical pickups in those Aiwa systems fail a lot. I would
just replace the pickup since they're not that expensive. Modern CD
players hardly ever need alignment.
Andy Cuffe

[email protected] <-- Use this address until 12/31/2005

[email protected] <-- Use this address after 12/31/2005

 

[Arfa Daily]

The Sony optical pickups in those Aiwa systems fail a lot. I would
just replace the pickup since they're not that expensive. Modern CD
players hardly ever need alignment.
Andy Cuffe

[email protected] <-- Use this address until 12/31/2005

[email protected] <-- Use this address after 12/31/2005

If you want a quick easy way to set the focus bias, when you've replaced the
laser, or done whatever you need to get the player going ( and yes, I agree
that laser failure in Aiwas is VERY common ), just set the focus gain up
higher than normal, and play a less than perfect disc. Stick your ear down
close to the laser, and you will hear the tracking noise from the surface
scratches. Now carefully swing the focus bias pot either side of centre, and
listen for the null in the tracking noise. Set the pot to this point, and
leave it. The tracking balance pot can be set in the same way, but you have
to listen a little more carefully. Set the tracking gain and focus gain pots
just on the high side of centre.

In the absence of the proper instructions, this rule of thumb setting
procedure, will work for any four-pot player, and give reliable results.

Arfa