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Of Pin Straightening and CMOS Batteries

Whilst rebuilding a motherboards thought long dead, I have been required to perform a myriad of tasks. These have been related to anything from re-building PCB traces to fabricating batteries to straightening IC pins. Honestly, there's nothing quite like a good challenge and, recently, there's been nothing short of serious challenges appearing on my workbench!

CMOS Batteries

Some older motherboards have the batteries soldered on... or worse... incorporated into the freaking CMOS RAM chips! Luckily, this latest motherboard had no provisions for an on-board battery. Instead, it just had the usual 4-pin header for an external battery. Of the four pins, the two next to eachother are ground and the single pin to the side is positive. Don't be fooled by the CON1 label thinking that anything with a 1 should be positive!

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I ended up at the usual Jaycar franchise and purchased a coin-cell holder and plug socket. It's a little chunkier than a standard header, but it is so much easier to work with!

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Solder everything up and determine which way is positive. Note that, for coin-cells, the positive side is the 'bottom'. I had always assumed it'd be the 'inner-ring' (as per AA and AAA and all other batteries)... but it ain't. So be careful!

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Once rigged together... install!

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Yosh! Worked like a charm. If only all motherboards came with external batteries... the next mobo on the shelf has so much corrosion that I just feel like throwing it out.

Pin Straightening

Whilst doing the previous Recycle-Shopping-Tour-Of-Kumamoto, I stumbling across this 100-yen dream. It's a 386/486 era CPU with an alloy heatsink to obscure its actual identity!

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I spent no extra effort breaking it out of the bag... and probably bent more pins... I wonder if works? Or what spec it is?

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First step... pop that heatsink off. This required a fair amount of jimmy'ing...

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Ooooo! It's a 486 DX2/66. This is seriously my favourite 486 CPU. So much natsukashiiii.

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Will have to find a motherboard to slap it into... but before I even have a chance to do that, it's time to break out the tweezers. Actually, I discovered a better method this time around. Use a credit-card/transport-card/library-card to align an entire row of pins at the same time!

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Nothing like being an adult and using adult tools!

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About stevenh

Trains... trains... trains... + Electronics + Japan.
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