Hi. I just picked up a cherry audio filter. Of course, it came without documentation. It is a ERC Model SL-56.
I am looking to PURCHASE a copy of the Manual/Schematics. It works fb on CW, but when switched to SSB, it makes a crackling 'white noise' and the signal disappears. Inside looks mint but the ICs are hardwired... (but I can change that! ha ha)
Thank you in advance for any leads..... Google is NOT my friend when it comes to this unit.