Need help reviving Sansui CD player

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Partly for sentimental reasons, I'm trying to revive my trusty old Sansui CD-X515 which has neither pedigree nor any documentation, but surprisingly, sounded quite good after the addition of LcAudio Xclock and some ad825 output IC's way back when.
It's based on a Sony chipset :cxa1782bq,cxd2507aq,ba6395fp and sm5874am.:
Previously the problem was intermittent,but recently it's continuous:it has the common "no disc" error display. The weird thing is, that when I reversed ac plug polarity it would work,but no longer.
After turning power on, laser comes on,but assembly does not go to home position. As well, the laser does not go through the up and down focus attempt.
I figured this is a power supply issue and so replaced all electrolylics,bridge rectifiers and voltage regulators, but no help.
My last effort was to replace a couple of transistors near the 'focus offset' trim pot. Again no use.
Any constructive suggestions (besides trashing the thing) would be appreciated.
The only instrument at my disposal is a DMM.
Thanks (and no jokes please)
 
I don´t know this model, but by the description of trouble, I think can be laser head are run out. If the beam laser don´t have sufficient power, don´t can read nothing, and don´t go to the home position, for start to read the disc information.
If the model of laser head is conventional you can encounter other, in especialized comerces.
 
The OP said the laser sled does not return to home position, so it is NOT the laser at fault. First thing to look for is whether or not the laser sled can move freely or sticks due to lubrication dry-up, then a tracking motor fault, then a tracking motor driver fault, then look around generally for cold solder joints throughout.
 
That is the ONE servo chip where I have seen a specific servo output pin go dead. So, you should check it's tracking motor control output pin/pins & see if they are doing what they should. If not, bad chip. Don't know if this chip is obtainable. In the DIP package one I had bad, I was not able to find one, and that was a good few years ago.
 
Thanks for everybody's replies. It seems that one of the leaf switches slipped behind an actuator pin of the drive's cog wheels. I just lifted the cog wheel and replaced it with the leaf switch in the right position. Voila!Works.
However regarding the BA6395FP, it's running quite hot during playback. Is this normal or a sign of things to come?
Thanks
 
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