Juno 106 no sound

[POR]

I know there are similar posts to this one, but all of them are slightly different (or have different symptoms) to the problems that I am experiencing.
My 106 is completely dead apart from a sound similar, but louder, to 106 chorus noise sound. If I turn the unit off and on again, this sound can vary (after each re-boot) from a chorus noise-like sound, or a low pitched rumbling phasing sound, or complete silence. The master volume control still works (can hear pot crackle), as do all the LED's and lights on the switches.
I have tried to clean the level switch, as I know this is an issue, but it makes no difference. Cannot do the voice-chip test for obvious reasons. I recently replaced a voice chip and the synth was working fine afterwards.
I suspect a power-supply problem. Any thoughts/ advice on the matter would be appreciated.

[HideawayStudio]

I know there are similar posts to this one, but all of them are slightly different (or have different symptoms) to the problems that I am experiencing.
My 106 is completely dead apart from a sound similar, but louder, to 106 chorus noise sound. If I turn the unit off and on again, this sound can vary (after each re-boot) from a chorus noise-like sound, or a low pitched rumbling phasing sound, or complete silence. The master volume control still works (can hear pot crackle), as do all the LED's and lights on the switches.
I have tried to clean the level switch, as I know this is an issue, but it makes no difference. Cannot do the voice-chip test for obvious reasons. I recently replaced a voice chip and the synth was working fine afterwards.
I suspect a power-supply problem. Any thoughts/ advice on the matter would be appreciated.

I would hazard a guess that the 5V supply rail has failed because the chorus in the 106 is powered by the +/-15V rails and so the amp and BBD sections will still be operating even though there will be no modulation of the VCO driving the BBD clock. This is not unheard of in the 106 for a couple of reasons.

[POR]

Thanks for the reply @ HideawayStudio. I'll wait for a few more before I investigate- I realise that it could be a number of things.