Hi all, and belated Happy New Year from the Highlands.

Just finished a refoam of my Pentas, and a full recap (thanks to Martins kit) of amp, and crossovers. No-load current set to 29mV and offset smack on zero. Circuit voltages checked are also o.k.

Speakers sound as good as new, with the exception that one speaker will not operate on med/max input level. Minimum level is fine and probably adequate for the BM5500 I'm currently using but I would obviously like to have them both fully operational.

Switching to med/max gives no output and a slight hum, and switching off gives a huge thump, like a cap discharging. Had a look at the circuit diagram and the only common component to the med/max switch positions seems to be the 4066 quad switch.

Not being more than an amateur I would welcome some advice or guidance from anyone more knowledgeable, or anyone familiar with the symptoms before I dismantle again.