Hoping to get some help diagnosing a problem with the protection circuit on this amp. This amp was given to me as non working. Initial power up on DBT passed indicating no major shorts. Symptoms on house power..., after initial power up, protection relay clicks after 5 secs as normal for muting function. After approx. 30 secs, relay will turn off. Then relay will continually cycle on/off with no real consistent time between cycles. Sometimes 5 or 10 secs. Sometimes longer. I have researched as much as I could find on this but not in total understanding of how this circuit works. Any help would be greatly appreciated. The one document I could find from the Pioneer Tuning Fork article on troubleshooting protection circuits, mentioned that if the relay turns on after the standard 5 secs after power up, it is likely a fault in the detection side rather than the relay driver side. The output transistors passed testing (in circuit) for shorts and they have the correct voltage on all collectors with power on (41vdc, -41vdc). Not sure what to include here for diagrams and the SM from hifiengine is of poor quality.