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Mr_F

Marantz CD65 Repair - Help Needed

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Hi all,

 

Recently acquired a Marantz CD65 which is not working, and I am determined to fix it.

It powers up, reads the disc fine and when you press play, you can see the track timer start counting. However, the only sound that comes out the speakers is a loud sporadic popping.

 

So far, I have swapped the decoder board (with the DAC on it) with a known good one from a friend's unit, which worked perfectly in my player. So I know that the fault is in the decoder board.

I have replaced the 24 larger caps on the board, as they were the easiest to do, but it made zero difference.

 

If anyone has any pointers on how I can diagnose what section of the board the faulty component may be found, or any ideas on how I can test it further would be much appreciated.

There must be at least another 100 bits I could replace to no effect!

I will attach a couple of photos to show what the board looks like and which caps I have changed.

 

Thanks in advance!

 

Nath.

CDP.jpg

CDPb.jpg

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Posted (edited)

Maybe check the diodes or rectifiers in the power supply, from there I don't know, but maybe a systematic checking of things through the circuit from input through to output.

 

A player with lots of potential if you sort out the issue, I have one the same I did a simple mod on.

 

Maybe someone else will help better than I.

 

Edit: heh...that TDA1541 is close to mine, same year and week with a slightly different batch number 3864.

 

 

Edited by Muon N'

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A quick look at your photo of the underside, seems to my eyes there are a number of suspect solder joints, especially around the area where the TO220 packages are situated.

 

It would pay to check the all the board with a magnifying head set or a loupe, just to make sure all the joints are solid.

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Nath,

Normally, I would suspect a muting circuit. The one that mutes the output between tracks and before audio starts flowing. It is either done with relays or with special transistors that can sink a lot of current fast.

In this unit I think muting is done within IC6304 (SAA7220) and your culprit is the headphone jack which sends KILL signal to the audio board and shorts the output.

Quick check is to try its digital output which should still be working if my theory is right.

Hope it helps.

Roman

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I'm not sure if this will help, but:

 

I have just fixed my Philips CD104 and the circuit board had solder links which look identical to the ones on your board.  I'm referring to the large 'blobs' of solder on the top surface.  On my boards they were a recognised weakness as they are solder links which join the top surface to the under surface through the board like a rivet.  With time, some of them go 'dry'.  The recommended solution is to replace them with a short wire link through the hole, soldered to both surfaces.  I replaced 11 of them in my player and it works like new.

 

Good luck.

 

 

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Thanks guys

 

I assume power supply is ok as everything functions as normal on the player except for the sound. I suspect the fault lies within the components that deal with the audio signal between the plug from the CDM2 and the RCA outputs. The solder joints as far as I can tell are ok, although I will try reworking a few of the poorer looking ones.

 

The solder links on the top side I thought were a bit odd, will replace those as Graceman suggested.

 

I never even thought that the headphones could mess with it, it doesn’t work with headphones in or out. The popping sound it makes when trying to play sound is quite similar to when you plug or unplug headphones though so you might be onto something there Roman. I’ll see if I have something at home I can plug the digital output into. 

 

A bit of background, the bloke I got the player off said it was working perfectly last time he used it, but when he got it out to test for me it no longer worked. I was supposed to buy it off him but he ended up giving it to me for nothing, wouldn’t even accept $20 for it. Very nice guy.

 

Anyway, have a few things to try, will let you all know how it goes,

 

Cheers,

Nath

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Can you disconnect the headphone board so it is not in the game? I think that was the first thing I did with mine in pursuit of better sound.

 

The guys have great suggestions above and likely know more than I, but always remember that the power supply is powering that circuit and all the chips in it. Maybe test the voltage on the power pins of all the chips and see if they are all in a range they should be. But try what has already been suggested first of course.

 

Best of luck, sounds like you will get there sooner or later.

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Having re-read the notes on my CD104, I am more convinced that you should start by checking those solder links.  Don't just float a hot iron over them but clean the solder off the top and check if there is a wire link.  You may be able to see evidence on the underside but it is unlikely.  Some of mine had been redone - or so I was told, but on checking they had just received the hot iron treatment and had gone open or intermittent circuit.  it's a bit of a chore, but worth it in the end.

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 Years ago I had a highly modified CD65 but I had a never ending battle with high resistance  IDP connections, and ended up soldering quite a few.

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Invest in a cheap oscilloscope and a service manual. 

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Might want to ask the bloke you got it from what the previous repair was for. Or did you rework some of the solder joints already?

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Sorry Graceman , your CD104 is a different vintage. The rivet faults are on in this early generation machine only.

 

 

To the CD 65. Substitution Servicing ( without scope etc ) 

If the fault hasn't changed since you got it ( was the same popping when demoed to you ), the the fault may be in the digital filter / DAC. 7220 / TDA1541P or something around this area. You've replaced Caps so you can probably add sockets to both Decoder Pcbs ( your & friends ) & swap over the 2 IC's, one at a time. A little tricky , but with some care you can put new DIP sockets ( 24 std & 24 narrow ) in after carefully removing the old ICs . Do the same to your friends one & test after each procedure. This may help to eliminate these, or identify one as faulty. Sockets are great to have in Philips Machines anyway. 

 

F.A.B.

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