MESA Carbine M9 Bass Amp Repair

Here’s some photos from an emergency repair I did for the band Swans.

I got phone call from their tech saying that one of their amps. a MESA Carbine M9, had died with smoke emanating from the innards.

Swans needed the amp turned around quickly as they were on tour. I said that this didn’t look promising but I would have a look at it; smoke is usually a bad sign, and if say the output transistors had died it’s unlikely that I would have the correct parts in to affect a repair.

Anyhow, when I got the amp the source of smoke was fairly obvious:



This an insulation displacement connector (IDC) which connects the power transformer secondary windings to a PCB. IDC connectors rely on blades in the connector to pierce the insulation in the connecting wire.

IDC connectors are generally used to aid assembly/ disassembly. However you can experience problems with IDC when passing high currents eg in a 600W amp! Other manufactures have had problems with IDC connectors for the filament supply in valve amps, eg Bugera in their 333XL.

Anyhow, the I removed the connector and soldered the wires directly to the PCB and we were up and running again.


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