Marantz CD65DX help

[RichG4PCE]

My player has got an intermittent fault in that it reads the TOC ok, but when playing there is a burst of audio, and then silence and 2 or 3 seconds later another burst of audio.
With no disc, there is a strange faint pulsing audio sound that cycles every 3 or four seconds.

Sometimes it works just fine!!!

The voltage rails all seem ok

Any ideas??

Rich

[amc184]

That's quite an unusual fault. First, a few questions:

- How much experience do you have with electronics, and what test gear do you have?
- Did the fault appear suddenly or develop slowly?
- Did the fault appear without an apparent reason, or was the player dropped, modified, bought etc.?

Those questions aside, it sounds vaguely like a decoder fault, but possible a servo fault. What are the state of the electrolytic capacitors in the player? Are they still original?

[RichG4PCE]

Hi amc184,
The fault has come and gone on three occasions. Started about 6 months ago, but the player doesn't have a huge amount of use. Its ok at present.
I am a radio ham, and have built radio gear. I have meters, sig generators, and a nice big Tektronik 851A scope, not storage though.
I must confess to not knowing anything about CD players!

[sandyK]

The Marantz CD65 being quite an old player, appears to be very prone to IDP connector problems. I ended up soldering many of mine, but I would no sooner fix one than another would start playing up a few months later.( sometimes less)

SandyK

[stephensank]

Given it's fundamentals, the most likely cause of trouble is caps. It's always the German electrolytics(Philips, Siemens, Roederstein, etc.) that go first, followed by any Matsushita/Panasonics that might be in there. If it were mine, I'd just go through and replace every lytic cap that isn't already a Nichicon with Nichicon. This and resoldering of any suspect connections is all that this generation of these players needs, 95 times out of 100.

[amc184]

Replacing the electrolytic capacitors is a good starting point. Even if they're not causing the player's current problem, they'll give you issues in the future.

It could also be a connector problem, but it's not that likely. Sandy, the CD65DX is quite different to the CD65, it has a mainboard containing most of the player, rather than the CD65's separate decoder and servo boards. Hence there is a lot less cabling.

After you replace the capacitors (assuming that doesn't cure the fault) I would start looking through the servo with a 'scope and comparing waveforms and voltages with those in the service manual. PM me if you don't have it and I'll email it to you. This is a somewhat unusual problem, so you'll probably have to do some in depth trouble shooting rather than applying a known fix.

[RichG4PCE]

Thanks all.
I will replace the caps then. amc184. Thanks for the offer, I'll PM you after I do the caps if that doesn't fix it and scope about as you suggest. Its a 581A scope, a monster but has a good plug in, a type 82. Its served me well fixing old crt tvs.

Cheers
Rich