Date   : Fri, 09 Apr 2010 14:40:21 -0500
From   : jules.richardson99@... (Jules Richardson)
Subject: Testing homemade Master battery pack

Mike Tomlinson wrote:
> In article <e0622afa2f3aee1e7def2a8dc69c0800.squirrel@...>,
> Tom Seddon <tom@...> writes
> 
>> does anybody have
>> any hints on what I should do to test it?
> 
> just check for 4.5 volts on the connector plug.
> 
>> I was just going to leave the thing on
>> overnight and check tomorrow that the batteries haven't exploded, or
>> warmed up any... would this be enough of a test?
> 
> Hmm.  Did you fit the diode as well?  If not, better unplug the
> batteries straightaway.
> 
> Acorn's battery packs were 3 AA Duracells in heatshrink wrap, wired in
> series, and a diode was fitted to stop the Master trying to back-charge
> the non-rechargeable Duracells.  The pack tucks neatly into the gap on
> the left-hand of the keyboard, which just happens to be the right size.
> 
> Prior to that, Acorn had used a 3-cell battery holder taped to a metal
> bracket which was fitted in the space where the Domesday SCSI board
> goes.

So the holder in the SCSI area was earlier? I'd always assumed it was later, 
because it seemed a neater solution given that the batteries would eventually 
need replacing (and you could take them out and use them elsewhere if you knew 
you were going to be storing the machine for a long time).

I'm reasonably sure my ones with holders have the diode, but as they're not 
with me I can't confirm (I *think* it was in the lead with heatshrink around 
it, unless I'm mixing that up with some other system)

cheers

Jules