Dillen wrote:

The drive is held in four rubber supports. They dry out and break apart, causing the drive to rest on
the chassis when certain circumstances are given - like f.e. when the drives center of gravity shifts as the lens moves in and out.

Currently working on new parts...

Martin

Good to know Martin ! These have been a very annoying issue on otherwise perfectly well-preserved and working machines.

Is this just a 7000 / 6500 / 5500 issue or did they have the rubber supports on the CD50?

Cheers

Nigel

5500, 6500 and 7000 only.

The CD50 has a completely different drive type.

Martin

Good news!  After being powered up for more than two days my CD 7000 now plays an entire CD perfectly.  I tried different CDs and different tracks and they all played without any issues.  This seems to confirm that the problem was not mechanical such as a dirty lens or damaged rubber mounts. My friend who is a EE tells me that old capacitors which have not been powered for a long time (in my case 10 years) can sometimes be "reformed" after being powered on for days.  It's probably a good idea to recap the servo board before it fails again but at least I believe I know what the problem was now. Thank you Dillen and all others who commented here for their suggestions.

Hi all,

 Sorry for reviving a zombie thread. Am facing the very same issue.

@Weebyx - You say that it has to be a blue Philips / Vishay capacitor. Let me be honest, my circuit knowledge is very limited, but since it's a cap in the power supply for the laser, should this really matter?.

All I could get my hands on this morning was a no brand 47uF/25v - and it certainly improved the skipping issue, but didn't fix it completely. (Also cleaned the laser with an alcoholic wet wipe and wiped dry afterwards).

It doesn't look like Dillen has the cap kit in his store anymore unfortunately :/ - Should I try to find a Philips / Vishay cap before I do anything else?

BR, and thanks, /Steffen

Flerbizky wrote:

Hi all,

 Sorry for reviving a zombie thread. Am facing the very same issue.

@Weebyx - You say that it has to be a blue Philips / Vishay capacitor. Let me be honest, my circuit knowledge is very limited, but since it's a cap in the power supply for the laser, should this really matter?.

 

All I could get my hands on this morning was a no brand 47uF/25v - and it certainly improved the skipping issue, but didn't fix it completely. (Also cleaned the laser with an alcoholic wet wipe and wiped dry afterwards).

It doesn't look like Dillen has the cap kit in his store anymore unfortunately :/ - Should I try to find a Philips / Vishay cap before I do anything else?

BR, and thanks, /Steffen

Yes, get the blue vishay capasitor before doing anything else.

You should also change the other non-smd caps, they should just be of good quality, no special needs there, and remember not to do any adjustments on the laser current to try and fix it, at least not until all cap(s) have been changed, and you can measure the current to be off.

I have seen a deck with a "Serviced by B&O" label on the PCB, that did not have the original vishay cap, and did not work. After changing to the correct type, it worked again.

/Weebyx

It's the only component of this type on the board, all others are other brands and radial.
It was chosen for a reason. Not because of its capacitance, but because of its filtering properties.
When taken out, the old (bad) capacitor typically measures fine (or at least wihin reason), but its filtering charateristics have gone.

A blue Philips/BC axial it must be.

Martin

Thank you guys.

So the random selected 47uF that the local store had in, didn't completely fix the issue, neither a couple other random branded 33uF and 47uF, so went ahead and:

  Did all the 4 supply caps as well as the one for the radial motor (2159, bipolar 470nF in the schematic, 1.5uF polar in reality - replaced with a bipolar 1.5uF Wima MKS 2-5 as suggested by Die_Bogener in an archived thread).

Also measured the laser current ("live", not in service mode) which should be 50mv +/-5mv. Gives me a constant 49mv, so even with my meter being crap, should still be somewhat ok'ish.

Did all the mechanical adjustments. Checked that the laser swings from end to end freely.

Yet. The issue persists -
  So Martin - do you happen to know where I can find a Philips/Vishay 33uF or 47uF (I think I'd prefer the 47uF from comments in the archived thread) in our vicinity (I'm almost in your neighborhood, have purchased a couple of your Penta kits earlier) or do I bite the bullet and buy them from Digikey as they have them in stock?.

Again, thanks hugely guys!
/Steffen

  On a completely different happy-hippo note- I rescued a CD X from a basement covered in ½ a cm of saw, concrete and plaster dust. Gave it a quick wipe down - haven't touched anything else yet, (didn't even wipe the laser), so far, it has played every CD I've thrown at it. Even came with the original external CD/Tape switch!

I have them.
PM or email me.

Great find! 

Martin

Either my soldering skills are getting really bad - or something else is wrong. I recorded the first attempt after replacing the no-name 47uF with the correct Philips one (Thank you HUGELY Martin!) - and much to my surprise, it didn't improve - actually, if anything, it made it a bit worse.

https://www.youtube.com/watch?v=fG6O9FYeuOw

Edit: My embedding skills are as poor as my soldering skills apparently

So I reverted to the no-name 47uF, same result, Martin was kind enough to sell me two of the Philips caps, so installed the other one (and crashed my phone while recording). -With this one, it seems better, but still not acceptable.

Any idea where to go next?.

[EDIT: 20180909]

Previous experience tells me (I'd long forgotten (last night at least) when I posted the above) that even boards that measure correctly when out, can change their behavior when mounted (pressure from screws etc.) - so even though I'd checked my soldering points before mounting the servo board, I double checked with the board in place this morning.

From the negative side of 2103 to the small jumper above (which should be ground) it reads 0.7Ω (told you my meter was crap ;) )
From the positive side of 2103 to pin 17 on IC6101 - same as above, 0.7Ω.

And from the positive side again to the base of TR6108 (passing through a 100Ω res) gives me 101.4Ω...

Thank you!
/Steffen