Poly 800 dead channel

[LoGiCa]

I was playing the Poly 800 (Mk1 Reverse keys) I bought off Ebay and it has been working fine for hours. I noticed some crackling when I played notes and now the left channel is dead.

I turned it off for a while and turned it on and the channel worked for 30 seconds, crackled and now its gone again...

I can hear this fast clicking sound in the dodgy channel when I turn the volume of the synth right down.

Any idea what is going on? has anyone had this issue.

Thanks

[LoGiCa]

Well this is weird. It seems to have sorted itself out now.Hope it stays like this...

[mrds]

I do have exactly the same problem (ok, not exactly...)
When the vol knob is turned down/almost off, then there's very quiet sound in both channels but when turned up it crackles a bit and the loses one channel.
Might be a faulty pot or something worse?
thanks