This Weekend's Finds

From: Philip.Belben_at_powertech.co.uk <(Philip.Belben_at_powertech.co.uk)>
Date: Mon Aug 18 11:06:03 1997

[My ascii circuit diagram]

> That looks like a voltage regualtor, which is strange, since I'd have
> expected a constant current charger for the NiCd. Of course a lot of
> machines just use a resistor to limit the charging current (and to get you
> to buy more expensive battery packs)

It does to me, too! By "to get you to buy more expensive battery packs"
do you mean that the packs are more expensive, or that they wear out
faster?

> > If the machine draws 60mA, minimum voltage at input is around 9V,
> > maximum around 13V, so I suppose I could try 10V and see what happens...
>
> Remember that you'll be charging this thing (probably) with the machine
> turned off, so it's not going to be taking much current).

Good point. 50mA then (8 < V < 12) based on the 14 hour rate on the
battery label. Looks like 9V is about right...

There is also a power switch but I haven't found where it connects yet.
(Not in series with the circuit I just drew AFAIK) Next task, I
suppose, is to trace that part of the circuit. Difficult, because most
of PCB tracks are underneath LCD module which is difficult to remove...

Philip.
Received on Mon Aug 18 1997 - 11:06:03 BST