[SPARCbook] Want to buy/fix: Sparcbook 3GS/3GX (internal power / backlight)

[Sunder]

"Scott D. Yelich" wrote:
> 
> It appears the laptop still works (ha, yes, even the screen), but I'm
> thinking that the internal power circuitry has been "shorted" somehow. I
> can run the machine off battery, but I can't run it off a dc plug. The
> dc plug that was in use when the surge came through is dead. I used my
> second one (one from tadpole), and the little power indicated led is
> solid green -- then I plug it in, and it flashes... and if I listen
> closely to the converter, it is buzzing along with each "flash" of the
> led.... and, of course, then you can "small" the electrical fire smell.

I don't claim at all that this will help you fix it, but it sounds suspiciously
like a diode bridge having one of it's four diodes broken.  I had that happen
to several bits of equipment where the power lights would flicker and/or
click.  It's likely not the only thing that's busted, but start there.

Bridges vary in appearance, some are just physically four diodes, others are a
small black flat block with four pins.  If you take a VOM and measure in all
directions (+,- and swap) you should be able to map out the diodes.

I've personally replaced a dead bridge with normal diodes and have had it work,
but I don't recommend you do that.

Again, it's likely not the only thing busted, but... whatever. :) It's a
starting point.  Likely, it's somewhere in the upper left size of the board
where the power circuits are.  Since I don't have an opened Sparcbook infront
of me  I can't say where's a bridge or not, but I'll take a look tonight if
time permits. :)

As for the dead (external) power supply, chop the plug off and visit a junk
yard.  Look for a transformer from another notebook with the same voltage
output and at least the same amp/wattage rating and patch the head on it being
careful not to swap +/-. :)  Don't worry if the amp/wattage of the new adapter
is higher.  The sparcbook will only draw what it needs (unless you supply a
ridiculously high amperage it'll be ok.)


I do however have a favor to ask and am willing to pay a reasonable price. If
you do come across a broken sparcbook, I'd like to buy it's keyboard (if it has
a working rat.) :)

While you're at it, if anyone has a dead battery they're willing to part with,
I'd like to have a whack at refurbishing it with NiMH AA's...


> Anyway, now I'm looking to fix this machine as well as the sparcbook
> with a bad backlight.  If anyone has a dead 3GS/3GX and they would like
> to sell it for relatively cheap, please let me know.  I fear calling
> tadpole and finding out how much these parts would cost through them.

Backlight could be anything from a broken backlight which would be a bitch to
replace, usually, you'll have to replace the entire LCD, or could be a crimped
wire... but that's another thing a dead sparcbook will be good for. :)

 

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