Revox B285 geht von allein an =[

Hi Ecki,

This may be a very difficult problem to cure.
Intermittent faults are the worst
Of course someone on the forum may have previous experience with this kind of problem and come to the aid.
If NOT, I can suggest to take a look around the Microprocessor-circuit. The Stand-By power-supply (5,5Volt) is build around a LM-317T 3-terminal voltage-regulator and if you don't really know what that means I suggest you stop here and let a qualified technician look at the receiver.
If however, you do know, the IC is on the Micro-Processor board, position IC-10. I would replace it along with electrolytic capacitors C33/10uF, C26/10uF & C34/2200uF.
Now, at least the Processor-Power should be OK. If that doesn't cure the problem look for bad solderings on the Processor-board.
The service-manual may come in handy if you know how to use it. PM me with your e-mail address for info if you need it.

mfg,

/tri-comp