RR--
Active Member
Thanks for the suggestion, I've been listening all day and it seems to be behaving and sounding sweet, there was however briefly what sounded like mobile phone interference in the right channel which is very unusual. I'll keep my trusty chopstick at bay when the time comes and post the results.If the issue changed sides then the problem lies in the pre-amp section. Will have a look at schematics.
Edit---
Nothing transistor related jumps off the schematic at me as a problem child so lets try this. Use tape 1 as input, tone controls and filters off, see if it mis-behaves. If it does try tapping on the protection relay and see if the sound returns. This is where a scope would really help as it allows us to 'see' fluctuations in signal level from board to board. If no results from this series of tests and in absence of a scope the next step will involve pulling first the tone board and then the eq board but I get ahead of myself.
Also just an unrelated question, in your experience do AU-719's tend to smell? It always has, I had just got used to it over the years, after using the 8080 quite a lot recently I'm noticing that it's just the 719 that does it. Kinda musky and old once it has warmed up, not like burning smell at all. I think it must be the different output transistors or circuit board material used.