reverse-engineering power

From: Doug Yowza <>
Date: Sat May 16 23:04:50 1998

On Sat, 16 May 1998 wrote:

> Did it have the battery at all?

No battery.

> first: hook up the voltmeter to the 74xxxx chip for 5v and ground.

I'm reading around 3.2V, which would make sense for a laptop.

> second: hook up that power jack with right size coaxial plug and to
> veriable regulated power supply at least 600mA limited

My variable regulated supply is in my other suit (I really do have one,
just not here), so I used a bunch of different wall warts instead (center-
negative isn't nearly as popular as center-postive, it seems).

> third: start at 6V and chank up in 1V steps until it starts to work
> properly especially for the display's crisp startup lamps.

Well, the good news is that there's no smoke. But I'm not getting any
lights either. I'll try to find a real power supply tomorrow and try

Thanks for the help. My diagnostic skills are now floating above zero
thanks to you guys.

-- Doug
Received on Sat May 16 1998 - 23:04:50 BST

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