5 Mar
2003
5 Mar
'03
8:38 a.m.
My multimeter shows the following voltages on the
mate-n-lock connectors
J3,5,7,9,11 relative to pin 8 (ground):
+15V at pin 6
+5V at pin 12
-15V at pin 15
The printset -- specifically, sheet 2 of 5410864-0-1 "PWR DIST BOARD" (page
40 of the BA11-K FMPS PDF I downloaded) -- leads me to believe that these
voltages can come only from the H745.
Are you sure? I've not got the prints in front of me, but I thought all
the -15V lines came from the H754 module, and the +5Vs from
H744/H7440/H7441 modules. With the +15V coming from the PCB under the
mains transformer.
Oh, hang on.. I know what you're seeing, I think. Those are the Vb
(battery-backed) lines. The battery backup interface brick fits in place
of the H745 -- the idea being that you only need the H745 if you have core
memory, which is non-volatile, and you only need the battery backup unit
if you have (volatile) MOS memory. The battery interface uses a different
8 pin mate-n-lock connector in the harness, though.
If you don't have the battery backup unit, then the Vb lines are linked
to the normal rails via jumpers (on the backplane I believe).
-tony