Tuesday, January 04, 2011

I've depleted my stash of basket case amplifiers on hand, so it's time to crack the case on that Peavey 260. Don't worry, there are plenty of basket case amplifiers and so forth that will be looked at in the future, I just have to dig them out.

Access to amplifier transistors is about as easy as it gets. My original hunch on this amp, that carried 39 volts DC on the signal pin of the output jack, was that of a failed power transistor. These all tested good, so my suspicion has been downgraded to failed driver pushing the output into saturation or good old fashioned funkiness with the connections.

These sockets may have to go. I'm weighing out my abilities to polish/inspect the connector surface, while my mind keeps interjecting "remove and replace". Honestly, circuit analysis while charged seems pointless while these sockets are cradling the pins of the output devices. I should also mention that the pins on the TO3 transistors are also less than pristine, almost as if something has been electrochemically corroding them.

The power supply capacitors are clearly in need of replacement, physical distortions are evident.

I also don't approve of the mains ground termination, pictured here tying in with the sleeve of a speaker output jack. This makes for a completely mechanical joint, relying on the nut that holds the jack in place to complete ground. I'm guessing, if you're reading this, that you are familiar with these nuts of which I speak. They wouldn't be my first choice for a safety feature, but this isn't the work of Peavey, it is a retrofit to three prong from the OE two prong power cable. Better than nothing I guess, I'll still change it to satisfy my standards.

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