Marantz CD85 won't play past track 16

Tweedle12 · 07:21 PM

Hands up - I'm a bit of an amateur, but I can work to ensure electrostatic safety and can usually work things out. I have a modified Marantz CD85 that I bought faulty - the control/display panel was not working. I have found another standard CD85 and today swapped the front panels and was mighty pleased when the modified CD85 actually played, very well.

My disappointment came when I tried to load up a long CD with 20+ tracks and the 'fixed' unit refused to play any track past 16.

1. Can anyone help me (in simple terms) with a suggestion of what might be wrong?

2. My second option is to remove the fully functioning transport, mechanism assembly from the donor CD85 and install it into the modified player. Is this as simple as unbolting the bottom screws that attach it to the chassis and changing them over, or would laser alignment and other adjustments 'in situ' be required? I have done such a swap before with cheaper players without a thought and they have worked fine, but this is a high end unit with 3 external power supplies, custom off-board DAC unit, etc, etc, that I don't want to mess up. I would have no way of having a laser aligned.

Any advice would be very much appreciated

Cheers,
TD

poynton · 2nd March 2012, 07:53 AM

Just change the boards over.

No laser alignment is required.

.

stephensank · 2nd March 2012, 04:59 PM

If the unit won't play past track 16 on more than one cd, with 16 at different total time points, then you have a very weird fault. However, if it is at a fixed time point that it will not go past, then it would seem to be a simple mechanical issue with laser movement, for which you simply need to find what is interfering with outward travel. If it is a different time & track point from cd to cd, most common cause is dying old capacitors in the servo, so any old caps that are not Nichicon should be replaced to cure the fault. Second most common cause is simply laser current mis-adjustment. This adjustment is made simply with a voltmeter. However, most people & servicers get it wrong, as they are unaware that adjustment needs to be made on many, many cd's, to assure a good compromise range, so that as many as possible fall within a 10mV window above/below the specified reading.

Tweedle12 · 3rd March 2012, 07:29 AM

Many thanks for the kind comments. On further investigation, I find the unit refuses to read one particular CD, plays all 20 tracks on another - so a bit hit and miss. I think I will just install the spare assembly.

Cheers,
TD

stephensank · 3rd March 2012, 07:27 PM

If you exchange transports, unless you also exchange the servo board, your current adjust will be even further out of whack than it currently is. The current adjust is not hard at all, if you can find a close enough service manual to your unit's internals.

Tweedle12 · 5th March 2012, 07:47 PM

Quote:

Originally Posted by stephensank

If you exchange transports, unless you also exchange the servo board, your current adjust will be even further out of whack than it currently is. The current adjust is not hard at all, if you can find a close enough service manual to your unit's internals.

Ah, thanks indeed. I'm assuming that the servo board is part of the board mounted underneath the CDM1 mk2 mech on a CD85, so if I replace the complete assembly, all should be well?

Cheers,
TD

stephensank · 6th March 2012, 01:46 AM

Quote:

Originally Posted by Tweedle12

Ah, thanks indeed. I'm assuming that the servo board is part of the board mounted underneath the CDM1 mk2 mech on a CD85, so if I replace the complete assembly, all should be well?

Cheers,
TD

Theoretically, yes, but only if the blue, axial 33uf cap in the middle of that board isn't yet dying or has been replaced.

1st March 2012, 07:19 PM	#1
Tweedle12 diyAudio Member Join Date: Jun 2010	Marantz CD85 won't play past track 16 Hands up - I'm a bit of an amateur, but I can work to ensure electrostatic safety and can usually work things out. I have a modified Marantz CD85 that I bought faulty - the control/display panel was not working. I have found another standard CD85 and today swapped the front panels and was mighty pleased when the modified CD85 actually played, very well. My disappointment came when I tried to load up a long CD with 20+ tracks and the 'fixed' unit refused to play any track past 16. 1. Can anyone help me (in simple terms) with a suggestion of what might be wrong? 2. My second option is to remove the fully functioning transport, mechanism assembly from the donor CD85 and install it into the modified player. Is this as simple as unbolting the bottom screws that attach it to the chassis and changing them over, or would laser alignment and other adjustments 'in situ' be required? I have done such a swap before with cheaper players without a thought and they have worked fine, but this is a high end unit with 3 external power supplies, custom off-board DAC unit, etc, etc, that I don't want to mess up. I would have no way of having a laser aligned. Any advice would be very much appreciated Cheers, TD Last edited by Tweedle12; 1st March 2012 at 07:21 PM.

2nd March 2012, 07:53 AM	#2
poynton Magneto the Gravity Man diyAudio Member Join Date: Mar 2005 Location: A life on the ocean waves when I'm not at home in N. Wales (but I'm not Welsh so no sheep jokes!)	Just change the boards over. No laser alignment is required. . __________________ If it ain't broke, break it !! Then fix it again. It's called DIY !

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2nd March 2012, 04:59 PM	#3
stephensank diyAudio Member Join Date: Oct 2006	If the unit won't play past track 16 on more than one cd, with 16 at different total time points, then you have a very weird fault. However, if it is at a fixed time point that it will not go past, then it would seem to be a simple mechanical issue with laser movement, for which you simply need to find what is interfering with outward travel. If it is a different time & track point from cd to cd, most common cause is dying old capacitors in the servo, so any old caps that are not Nichicon should be replaced to cure the fault. Second most common cause is simply laser current mis-adjustment. This adjustment is made simply with a voltmeter. However, most people & servicers get it wrong, as they are unaware that adjustment needs to be made on many, many cd's, to assure a good compromise range, so that as many as possible fall within a 10mV window above/below the specified reading.

3rd March 2012, 07:29 AM	#4
Tweedle12 diyAudio Member Join Date: Jun 2010	Many thanks for the kind comments. On further investigation, I find the unit refuses to read one particular CD, plays all 20 tracks on another - so a bit hit and miss. I think I will just install the spare assembly. Cheers, TD

3rd March 2012, 07:27 PM	#5
stephensank diyAudio Member Join Date: Oct 2006	If you exchange transports, unless you also exchange the servo board, your current adjust will be even further out of whack than it currently is. The current adjust is not hard at all, if you can find a close enough service manual to your unit's internals.