Help needed to sort amplifier out

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I recently bought an Acurus A250 power amp off the forum. Seller disclosed that one channel had a problem with intermittent static noise. What he neglected to mention is that a well known to forum members technician has worked on the amplifier and was not able to cure the problem. Work that I can see that has been done is resolder all joins, output transistors were replaced and the power supply capacitors were replaced. I also noticed that it looks as though the bias pots were removed.

The boards are simple enough to swop out components until the fault disappears but before I do so I thought that I should get some input from the power amplifier gurus on the forum. Are there any components that you would change first that would be the most likely culprits?

When the amplifier plays it sounds absolutely fine, however the static noise (quite loud) would just randomly appear in the right hand channel.

All suggestions would be gratefully accepted.

Schematic and pictures to follow.

 
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