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Author Topic: Twin Famicom Voltage Tolerance?  (Read 9120 times)
ifrit05
Famiclone
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Posts: 2


« on: November 26, 2016, 04:27:46 PM »

I got my Twin Fami in the mail today to start restoring. When you turn it on it shows a blue screen, so I thought it might be memory issues. I tested the 7805 and it's actually not regulating. I had 9v in, ~8.3-9v out!  Undecided

I tested it on 7.5v and it was outputting near 8v.

I am replacing it with a switching regulator, but I'm hoping the IC's didn't fry. What is the maximum safe voltage the chips can take?
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2A03
Twin Famicom
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Posts: 562


« Reply #1 on: November 29, 2016, 04:15:11 AM »

That's not a 7805, it's a 2SB941 transistor. The Twin Famicom has very different power circuitry compared to a regular Famicom since the PSU/AV board has to supply power to both the Famicom board and disk drive, and I found that if you go above 7.5V you run the risk of overheating or overvolting components. I once made the stupid mistake of feeding 9V to mine, and after about an hour it blew an op-amp chip in the disk drive.
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