Quadra 840av | Common Issues | Resources |
The 1/2AA Lithium barrel battery used for keeping track of PRAM settings on the logic board is prone to leaking. Several brands were used, but all will leak with age. These leaks can be absolutely catastrophic, with extremely severe corrosion being common. In most of these cases, the board is unrecoverable. So, remove those batteries!
Unlike many other Quadra models that only used tantalum capacitors on the logic board, the 840av used surface mount electrolytics, and yes, they always leak. The 840av board in particular is quite complex, so cap leaks can be a massive problem. It's worse if you have the revision board that's a brown color, as it makes spotting trace breaks very difficult. Check the resources page for a link to capacitor reference info for the 840av's logic board.
PSUs were never meant to last this long, and as such, many are failing in old Macs, the 840av included. Most of the time it's bad capacitors, so give a recap a go first before you go to replace it.
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