Thanks Keith, but it looks like this version (note twin potentiometers). Should I up the voltage to 50mV..? Or wait until the 33uF cap I ordered turns up, fit that, then adjust?

 

 

Further testing shows it is behaving oddly. When loading a CD it fails to read track 1, but select 2 and it will play. Then, select 1 again and it plays that! How come it can't play Track 1 when loaded, but a skip forward and back again and it works? Is this indicative of any known problem?

(By the way, I still have the 47uF Vishay cap at C2103 and the laser voltage at 21mV.)

 

Edit: Also I suspect a loose wire somewhere. On reseating the drive in its normal position it rejects the disk. Back in Service position and it is rejecting the disk. Settle it back down in its proper position and it plays. More testing (different CD) and it is rejecting, than after slight movement of the player mechanism, playing.

 

Edit 2: Scratch that - the servo board was shorting against the chassis (d'oh!) causing the disks to be rejected. It is still failing on Track 1 as before).

Don't touch the potentiometers unless you replaced the laser (or already messed with them).
Most read errors are down to bad (or wrong type) capacitors on the servo board, cracked solder joints at the large filter capacitors in the
power supply module and/or craced solder joints at the large transistors on the decoder board (depending on drive version).

And note that some manuals give a wrong point for measuring the laser "current" - a point that will never reach the stated readout, allowing the laser current to be set high enough to burn the laser.

Martin

Too late, Martin, I set the R3105+R3106 measurement to 1K per the manual and got 21mV across R3102 (previously it was 48mV). Unit is playing better now, but is unable to read Track 1 when a disk is first loaded - but after seek to Track 2 then back to Track 1 it plays. I've been searching the forums all day looking for answers. One post suggested it may be caused by dirt in the laser mechanism and that I should clean it, but I could not find any clear instructions on how to do this. I have cleaned the outer face of the laser lens but that is all I could get at. I've not removed the laser housing / cover yet. Any ideas how to proceed?

 

Edit: But.. there is a small bump stop on the laser carriage that looks to have become slightly dislodged. Its white plastic, like a little dimple that looks as if it slides in a groove. I pressed it home and cleaned it a little. Hasn't really helped, but I found if I load a disk then (when it is trying to play track 1) touch CD, it plays. Maybe it is going to pause when loading?

Just a thought.

When you LOAD a CD, is it supposed to start playing automatically, or do you need to touch CD to make it play? I've just reviewed the instructions, and it seems that LOAD on its own won't make it play. It just closes the door and indexes the disk. Which means that the behaviour I'm observing is normal. If I touch LOAD, then put in a CD, then touch CD it seems to work properly!

I think I've stumbled into a working repair... thoughts?

Hi jonbr,

Yes - this behaviour is normal. Opening the CD door, inserting a CD, then touching the LOAD button will close the door, spin the CD and load the table of contents. The BC9500 displays the available tracks and waits for you to either program a track sequence or just play the whole disc (by touching CD).

Alternatively, once you have inserted the CD, touch the CD control to do all the above automatically (obviously no track programming).

My BC9500 is my most beautiful, logical, well thought-out B&O product that I own.

Lawrence