Whitechapel Workstation - schematics
jrr at flippers.com
Wed Feb 6 11:38:42 CST 2008
> Does anyone have the schematics for the Whitechapel
> Workstation. I'm trying to 'rescue' a WCW that has
> the dreaded leaked battery.
> Its not made too much mess, but there is quite a bit
> of crystalised battery fluid mainly on the terminals
> of components directly beneath the battery.
> The WCW wont boot, although the disk drive and fans
> spin up OK, the front on/off button doesnt function.
> Although I can hear a faint click on the PSU
> 'controller' from the small relay.
> Any tips on how to clean this and/or anyone with a
> spare mainboard (too much to hope for but you never
> know) - :)
Leaky batteries have been a problem for many industries. My normal field - pinball and other amusement machines - has had this on going since batteries were first introduced back in the 1970s.
What leaks out of most batteries is an ALKALINE (not an acid!) - usually Potassium Hydroxide - and this can be neutralized by a weak acid. Eveready batteries technicians recommended to me back in the mid-80s that we use a 50/50 mix of white vinegar (clear) and water to stop the alkaline action. Then rinse with more water and dry. Scrape any coated traces as the alkalye leaches under the coating and will show up almost anywhere on a board! On ole pinball MPUs I've seen corrosion that skipped as much as 6 inches before showing up at the top of the board under a row of pin connectors!
You also should replace any components that have signs of corrosion on their legs - the alkalye will slip inside th device and render it erratic at best. So any resistors, caps, diodes, ICs, etc. that have any corrosion on the legs MUST be replaced.
Remove any IC sockets that show any signs of corrosion nearby...
If you (when the board has the suspect parts removed) then give the board a quick glass beading (like sandblasting, but gentler) and then a final 50/50 rinse, water flush, and dry carefully you should be able to save your board. I've managed to save many MPUs over the years with just this process. It does take time though...
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, VideoGames)
"Old pinballers never die, they just flip out"
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