Philips CD100/101 , Marantz CD63 overheating problem

I had two of those players and they were working fine but this one keeps overheating after an hour or so and the laser power supply goes down. It works fine without bottom cover. Before I start changing Regs and PTC resistor maybe somebody had similar problem with this family of players ?
 

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There could be a problem in conducting heat from the chips to the atmosphere.
Poor or degraded heat sink compound comes to mind, I would be very careful while working on old equipment whose parts are difficult to get.

Check all the voltages are within range, it could be that a component is heating up, replace all the electrolytic caps with 105 degree best quality parts, check the power supply stability.

Simple kludge solution is a small CPU fan in a suitable location.
 
Thank you. I will replace sink compound on power regulators.
It's a funny problem because it overheats and laser stops emitting and disc stops spinning. I open the player turn it around and it starts working again once the heat build up is released. It's unusual construction makes it difficult to disassemble quickly enough . The clue may be the fact that while hot it will continue to play CD but it will refuse to play it again after CD is stopped or changed .I can see the laser head moving up and down but no laser light is emmited. It would be far easier to detect fault with conventional box player . Capacitors were changed. Before the change it exhibited the same problem but it would only play one CD before refusing to play another without cooling down. Now it can play an hour or two until it heats up sufficiently. Bugger .
 
That means a componenet has come nearer to its tolerance.
Get hold of the circuit diagram, and see if you can read the temperatures with a scanning type thermometer.
Also, compare both units, it could be one is allowing air to circulate, the bad one has a block of air flow.

But this one will indeed be a 'bugger' to diagnose...