Saturday, September 10, 2016

Casual Amusement With a RSN311W64

While I was waiting on parts to repair my Marantz, I decided to scrap out a number of accumulated bits of equipment and loose PCB's.  One of these items was a 2000-era Panasonic surround receiver with DVD player.  I'd pulled it from service after it had slowly lost all audio output.

Panasonic SA-HT80

When I had first pulled it, I had intended to repair it.  Upon opening the case and seeing heat damage to the paper-phenolic PCB around essentially every semiconductor, I decided it wasn't going to be worth the effort.  I never bothered taking photos at the time, but disassembly was no longer possible without destroying things.  The board interconnects were so stiff that the damaged PCB's broke apart like crackers.  I amused myself by nudging transistors out of their fractured solder joints or peeling traces.  I pulled a large selection of capacitors from the board.  Out of about 50 capacitors, about 4 or 5 were not bad.  Almost all were less than half their original capacitance or had ESR > 50 ohms.  This included small electrolytics in areas of the chassis that were never abnormally hot.  I don't think I've ever run across a piece of equipment that managed to degrade so completely and uniformly without any catastrophic failure.

Totally not my photo

I kept the transformer and I pulled the generic-looking RSN311W64 amplifier hybrid for later.  That was then, so I guess this is later.  Since I was pleased with my attempts to photograph the STK3122 in the last post, I figured I'd pull out the phone and fight autofocus for a half hour and get some half-blurry pictures.

Let's pretend it's artistic.  If you aren't afraid of translating things, there are other dissections out there that had the benefit of more suitable tools.

As a bonus, I disassembled a Motorola SRF397 transistor and took a couple pictures.  It's not terrible considering it's handheld photography with a phone.

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