Sony CD-P 750 player static noise

Cracked solder joint? You shill could have a cap shorting, just not permanent.

Bad IC or semi.

Take a can of component cooler, it to make some noise and start freezing IC's, then caps etc..

Jamie

Gave the circuit board a good workout, and tried the component cooler, but no luck.

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Broken down DA converter or its input data?? Try heating/cooling locally, to see if there is a broken solder connection somewhere. Bending the print in various places, to see if there are bad connections. Last resort, buy a new one.

"Bert"

** By static noises you mean the sound of heavy rain or surf - right ? ** Likely to be in the digital filter, DAC or audio circuits, since it is in one channel.

Shame to toss well built gear like those old Sonys.

I still have a CDP101 ( bought new in 1983 ) in good working and cosmetic order.

.... Phil

If the problem is not the actual D/A converter, I would suspect the buffer transistor at the outputs. For this vintage of player, there sould be a couple of to-92 transistors just prior to the audio output jacks. Check/replace those.

Dan

The noise sounds like holding a small DC motor with bad brushes next to an AM radio.

There is an 8-wire ribbon cable going from the CD unit to the circuit board, close to a Sony 7M01/CXA1081 chip. When holding my finger near the cable, WITHOUT TOUCHING IT, the noise diminishes, and the audio/music starts to crackle and break up. Touching 4 of the insulated ribbon wires lightly will instantly stop the player.

When I ground my hand and THEN touch the same insulated wires, the noise stops also, but the audio - while continuing to play - becomes very distorted, and eventually stops as well.

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"Bert = Troll "

** OK - your Sony is obviously possessed by demonic creatures form Hell.

Or you are.

Take your pick.

.... Phil

I had more than a dozen Sony units from that era - a fabulous Trinitron TV, lots of high-end Beta and VHS VCRs, including a nice SLV-R5U SVHS VCR. Except for a rarely used Hi8 EV-S7000, they and that CD-P 750 player are all history now.

OTOH, I also still have a number of JVC units (high-end stereo, dual cassette, CD player...) from that same time period, and every single one still looks and functions like out of the box...

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No troll. It's a factual description of the symptoms. You can check it out and play with it any time you like.

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If it's still in working order, consider yourself lucky.

Yes, particularly since parts are likely not available any longer now - but what do you do with them, even when in perfectly working condition?

They were great for linear editing by providing a separate audio channel that could be edited without affecting the video, however while the EDIT switch was supposed to kill all on-screen text, you still ended up with some unwanted text on the finished video when pressing certain buttons while editing. Installing a small switch to shorten the on-screen dialog when editing fixed that.

Regardless, they still look very impressive just sitting there on the shelf taking up space...

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With this sort of fault you can often zero in to where the fault is ,with a crystal earpiece connected between ground and a probing pin

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Have you tried percussive maintenance on it.  Sometimes all they need is a  
good whack or smash with your fist. 

BTW:  I used it fix medical electronics......  scary huh?

?

board,

cable,

Offhand, i would say that you have put your finger right on the problem.

?-)