I've had to dive into several other projects since cracking this one open. I cannot recall if I removed the 8ohm load or not in Stereo mode. At this point I won't be able to work on this guy again until after the holidays. But, I'll get it singing again and follow-up. Hopefully not a nut loose at the controls! ...

I'm thinking the same. Something dumb....

I wondered about that too. There are a few amps that I thought might be candidates under the CRATE, PEAVY, or a couple commercial PA system amplifiers. But all were dead ends. I have about decided to just attack this one the old fashioned way and work my way through, tracing and checking for sigs and voltages til I find the culprit(s). I will take a look with the Thermal Camera in various states just for grins and note anything unusual as a matter of routine. I have noted that I am not the first person inside this equip, but the current owner has no idea about that. Whoever was inside changed...

Thx. I appreciate that. I found that SPA-240 Tech Notes too with the same thought. The 240 is a much beefier design and apparently a much more popular unit as it seems to be well documented unlike the SPA-100.. There are multiple board revisions on the 240 too, but none match up with the SPA-120. Still, one of the revs may give me some strong hints that prove useful. Thanks again....

CAPS: I focused on the same "ugly" Lytics. As stated, I pulled and tested w Kelvin Clips on Calibrated DE-5000 LCR Meter and Sencore LC53 (Value and Leakage). They may look ugly, but they're NOT the problem here. Haven't probed powered on yet. Only passive testing on obvious components, and found no abonormalities. Decided I'd like to find a schematic or Tech Notes for this SPA 120 unit if I can. So far, no dice. Not even for sale.

WAVEFORM / SCOPE: I usually snap pics of scope but I guess I forgot before teardown. When I power it up again I'll try to remember to get a...

Re: New Members - please post your introductions here

Greetings from Houston, TX! I'm Kenny. My career has been divided between high-tech computers and communications, followed by advertising and marketing. I know, right?

Anyway, I am a long-time HAM Radio enthusiast and experimenter (call sign: NZ5I). My electronics background is rather spotty in troubleshooting and repair over many years, mostly out of necessity.

Over the recent past, I have been equipping myself with the proper tools to deal with SMT, which has dramatically expanded my reach and...