Attach the ISS board to the back plate along with the IEC connector.
A quick wire up and test each channel.
And then it went wrong. Left guardian not working, but left Amp is. Right channel not working. Must have shorted something causing the amp board to blow up.
Ouch! Now to break apart and see what the issues are. Hopefully just replacement components for the ones which smoked.
Thanks to Tom at Neurochrome for his diagnosis assistance in determining that nothing else was broken.
Replacement green caps on. Tidied up Guardian boards. Back to testing on the scope to make sure everything is okay.
Bench test mounted Modulus and Guardian boards.
All looking good now.