Dead ZX Spectrum with burned components

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Flintstone
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Dead ZX Spectrum with burned components

Post by Flintstone » Thu Oct 18, 2018 7:49 am

Hi!

I just bought my very first ZX Spectrum - never had one as a kid :) It has had a hard past though, and probably was not worth what I paid for it.

Does anyone have a clue what happened here? Rev3 board - R55 and C46 seems to be burned both. I just assume this will happen again if I change these components, so maybe there is a different root cause?

Image

Not working at the moment of course...
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Ast A. Moore
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Re: Dead ZX Spectrum with burned components

Post by Ast A. Moore » Thu Oct 18, 2018 9:55 am

Ooo, that’s nasty. These components are part of the power circuitry. There’s a very good chance it killed some logic ICs. Still, you’ll need to check the voltage regulator, the inductor, and transistors TR4 and TR5 at the minimum.

C46 and R55 are part of the –5V rail. So, it makes sense to also check the diodes D11 and D12 and the 5.1V Zener (D16).
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Every man should plant a tree, build a house, and write a ZX Spectrum game.

Author of A Yankee in Iraq, a 50 fps shoot-’em-up—the first game to utilize the floating bus on the +2A/+3,
and zasm Z80 Assembler syntax highlighter.

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