Troubleshooting an Acme Audio Opticom XLA-500

Greetings everyone, I'm just looking for starting pointers to pass on to my tech regarding a very puzzling issue I'm having with a barely used Opticom XLA-500. Acme doesn't share schematics and their suggestion regarding what might be going on is to just send this to KMR in the UK for service, which, with me being in the EU, just leads to a similar logistics nightmare as sending it to the US. The only tangible thing they said might be going on is some sort of impedance issue, and they... Read more