Nakamichi TA2A Tuner Problem

[Fast Eddie D]

I have a TA2A receiver in my workshop. It is a very harsh environment for a reciever; it is not always heated and temps observed range from 10 to 110 degrees F.

When below 50 degrees F, the tuner doesn't work for a period of time after turning it on. The colder it is, the longer it takes to start working. It will start out with buzz and hiss. Then the hiss goes away and the music fades in, but a 120 Hz buzz is still there. Then there will be some popping and the buzz will fade out. A little more popping and then it works perfect.

I have never repaired a solid state tuner before. (I do know my way around an amplifier and in fact repaired the power amp in this receiver.) I have not opened it up yet, but I am thinking it might be an on board power supply bypass electrolytic or an on board voltage regulator. I have never found a schematic for this unit so I'll be kind of shooting in the dark. I really want to keep it in service since it really kicks out the jams and the only place I can crank it up is in my shop.

So any advice, schematics, or magic bullets are much appreciated.