[mowbot] XT Motherboard Current

Fred Thompson (fthompso nospam at mail.win.org)
Sat, 26 Jul 1997 08:42:48 -0500 (CDT)

We have been bouncing around on this list the price of XT mother
boards (lowest I think a little more than $9.00). And Dave asked how
much current they consumed. Well I managed to get one while they were
still $15.00 (lucky me), and I measured the current of it yesterday. It
is an all in one board which means it includes IDE, floppy, serial,
parallel and monitor driver circuits. However I have only the minimum
(64K) RAM. I performed the test using a standard switching supply and a
bare board, nothing plugged in. I connected the board to the supply with
alegator wires and inserted the current meter into one wire at a time
keeping the rest active. The voltages and currents measured are as

1 Orange 4.5V 0A
2 blank
3 Yellow 11.5V 15.8mA
4 Blue -12.1V -14.8mA
5 Black ground
6 Black
7 Black
8 Black
9 White -5V 0A
10 Red
11 Red 4.9V 1.45 A
12 Red

The orange wire on pin 1 goes to a connector on the board labeled
"Light." I did not succeed in tracing any of the other power circuits. I
also did not try running the board without the +- 12V lines connected. So
generally speaking, your supply would need to give the board 1.45 Amps at
least. The expansion cards that you might need may draw more.

Fred Thompson
fthompso nospam at mail.win.org