We have a Beocentre 5000 (1980, model 1804) which has recently 'frozen' in that the buttons do not respond to give an action or sound, although the power is getting through and the speakers are attached and working (hiss at high volume is the sign). 

The P LED, loudness  and indicator lights come on at start-up and radio lights up briefly, and you can 'force' the record player on by pressing turn then stop but it has no sound. It procedes to turn off after 'playing' but the red P light and loudness indicator remain on. Otherwise no buttons respond, including Standby.

Any experience anyone could  give in helping me to get it working again would be very much appreciated. 

Extra information..

 Last week I got it to restart by switching off and on but now no luck!

The tape recorder heads go on and off when unpugging.

Thank you, Rab

Welcome to Beoworld !  

I think, I would check the processor reset circuit first.
Then the power supply for stable voltage.
Cracked solder joints could explain the intermittent fault so that will also have to be checked.
Capacitors are to blame for many problems, also in these machines so
that will be a focus point too. A capacitor kit is available.
Finally, it could be the processor itself in which case I suggest replacing the
whole processor/display "sandwich" with one from a scrapped machine.

Martin