Schematics (parts list) and power

[Mitch Bradley]

James Cameron wrote:
> On Sun, Mar 25, 2007 at 12:54:42AM -0700, Hal Murray wrote:
>   
>> I think the pin is 1.3 mm dia, but that's only a good guess.  (1.7 is
>> too big, 1.1 is too small.  Digikey carries 1.3 mm parts.)  Can
>> anybody confirm the size of that pin?
>>     
>
> I couldn't get my vernier caliper into the hole.
>
> I wasn't able to find a good match in my extensive collection of spares
> for either the B1 or the B2.  The closest matches were prone to arcing
> if the cable moved.
>   
I dug around in my junk box and found some insulated wire that fits 
snugly in the hole in the plug.  That wire is 1.5 mm OD.

I then stuck the wire into the jack on the laptop and visually compared 
its size to the jack's pin.  The wire is slightly larger - the pin 
doesn't completely visually occlude the wire.  So 1.3 mm is a good bet.

I also tried a 1/16" drill bit (1.587 mm), which is slightly too large.



> So I cut the green cable.  This is for attaching the laptops to a
> automobile DC supply.
>
> http://dev.laptop.org/~quozl/2007-02-06/s08-348x.jpg
>
> 1.  disconnect power adaptor from AC supply and allow to discharge,
>
> 2.  prove discharge using a voltmeter and 100 ohm resistor, connected in
> parallel across the output plug,
>
> 3.  determine an appropriate location for the task (my cut was 100mm
> from the adaptor),
>
> 4.  observe or mark the polarity on the cable (the B1 power adaptors had
> a white ink mark on one of the conductor sheaths),
>
> 5.  place heatshrink over ends, strip ends, terminate, shrink,
>
> 6.  apply power, measure output, connect to laptop.
>
> In the photograph, the adaptor is to the right, the output plug is to
> the left.  The wires to the adaptor were anchored directly to the screw
> terminal block.  The wires to the output plug were crimped with 2mm
> spade connectors, since they would be regularly removed from the 
> terminal block and attached to another terminal block.  The heatshrink
> tubing acts as strain relief.
>
>