Hi, Hope everyone is doing well! I'm just wondering if anyone has any thoughts on these issues before I give up on them?

Thanks,

Greg

Don't give up on a CDX sir!!

In both your cases,the laser seems to be functioning as the disc wouldn't turn if it had failed.

Both cases seem to be due to the same thing-corrupted data from the disc,so the decoder is "dancing in the dark"?

The notorious griplets become oxidised within the solder,so I alway's drill through them,then wire through too,to make sure that the connection is good.

It's worth replacing the blue Philips(use the same type BC/Vishay)capacitors(33uf) on the little U shaped laser servo pcb mounted next to the laser assembly.Don't touch the presets there though!!!

If the capacitors on the decoder pcb are Nichicons,they will almost certainly still be ok,but if they are Philips,change them(22uf).

That lot should keep you busy?

Wonderful machines,well worth some tlc!

Keep us posted,

Nick

Hi Nick, thank you for the reply. I agree that these CDX machines do sound wonderful! I did de-solder and  feed thin wires through the griplet points and confirmed continuity from top to bottom of the boards so I don't think that's the issue.  I'll check the capacitors and report back.

Thanks,

Greg

Ok, so I replaced the caps on the u-shaped laser servo PC boards (even though they checked OK) and still have the same problem with both units. As mentioned in my original post, the first unit spins the disc but won't read it and then gets the "?" error on the display. The second unit plays fine for about 5 tracks, then starts skipping and having tracking issues. Any more ideas?

Thanks,
Greg

It could be an alignment issue with the door switch. I had a CDX that would not read and play when I loaded a CD and pressed play. I finally learned that I could gently press down on the glass door (on the left side) when it closed to help the switch engage and then the laser would read and recognize the disc. I don't know if that problem relates to you but it is something to check. 

Also, when you are test playing the disc is the CDX still apart or do you have it reassembled?  I had another CDX that wasn't loading and playing when I tested it all opened up but when the cabinet was all put back together it played great. 

They are cool little CD players but a little quirky.

-sonavor

The machine that is misstracking towards the centre of the disc,may need alignment of the disc motor lower bearing?This affect's the height of the turntable and so the focal length of the laser.It's quite a critical adjustment,but explained in the manual.

You don't mention the decoder capacitors I suggested for investigation?Are they Nichicons or Philips?

The power supply work that you carried out,might be significant?Are you confident now that all supply voltages are correct?

Nick

Sonavor, Thanks for the reply. I'm working with them apart, but I'm pretty sure the door switches are engaged otherwise it wouldn't attempt to play a disc.  I'll double-check them though.

Thanks,

Greg

Hi Nick, thanks for the reply....I'll check the disc motor bearing alignment in the manual and see if it helps.  It does seem like a disc motor issue as this is usually the cause of CD players that don't track well towards the end of the disc. Not sure why it would be out of adjustment, but we'll see.

As far as the capacitors on the U-shaped board... they were all Nichicon 33uf/16v expect the axial C2124 was a Philips 33uf/16v.  I replaced them all with good Nichicons and no difference on either unit. I even swapped the U-shaped boards from unit to unit with no difference on either machine.  I was surprised the one that plays until track 5 tracked with the different board, but it did. 

In terms of the unit with the power supply work, I haven't bothered to order the -18v and -6v regulators yet because I was frustrated and didn't want to keep spending money and time if I wasn't able to get it to play discs. But, during tests, I'm feeding a stable -6v and -18v into the circuit board with the output pin of the regulators disconnected.  I'm monitoring the voltage as it tries to play and it's not dipping down, so I was thinking that part is OK.  But, maybe I just need to bite the bullet and order the correct regulators.  All the other power supply voltages are good.  To be honest, I was surprised one unit could have so many different failures (open fuse, two defective regulators and disc reading problems)....  I mean, this thing must have been working at one point before it lost power, right?

In the meantime, I'll try the disc motor adjustments and maybe play around with swapping power supplies and CD mechanisms from one unit to the other to see if I can narrow down the issues.

Thanks again,
Greg

Ok Gregg.

Well,it seems as though you have two machines that have been "got at" by persons unknown?

Something we all dread,as this tends to confuse the issue.

I think that you will need to return the machines to as original as much as possible?

I'm puzzled eg by the fact that you have Nichicon caps on the laser  pcb 02.These are usually Philips axials.There is much discussion about the particular characteristics of the Philips caps,and they do seem to work best here.Polarity is crucial with some of the caps too,as there are both positive and negative supplies involved

You still don't mention the cap's on the decoder pcb 05.If they are Nichicons,fine,but if Philips,they are suspect.

Confused?

The fact that both machines spin the disc,and one indeed plays a few tracks too,makes me think that there is not a major failing.

You need to remember that these cd players employ three (later machines 4!)servo systems,that all must work in concert for the disc to play.The most crucial time is at start up,so any psu problems will have a bearing then!

I have the original training course notes somewhere,I'll see if I can find and scan them for you,if it will help?

Nick