6 Mar
2003
6 Mar
'03
5:51 a.m.
Ok, problem found: me. I got confused by the print set
on the representation
of front vs back views, and thus I had my regulator positions backwards. We
Wait until you sart populating a large backplane of flip-chips like an
RK11-C or worse a DX11. The printsets show the backplanes from the wiring
side you seen. Took me a bit of time to figure that one out (as in 'Hey,
why are all the PCBs in the wrong slots??').
were both also confusing the H745 and H754. Everything
(except one thing)
looks fine now. Here's what I have:
Under Xformer +15V
Brick 1: H745 -15V
Brick 2: H7441 +5V
Brick 3: H7441 +5V
Brick 4: H785 +5VB, +15VB, -15VB
The H785 doesn't produce -5V or +20, so it is certainly OK that I'm not
finding those voltages on the backplane power connectors!
Yep.
My current understanding (no pun intended) of the H785 is that when it is
not running off the battery, it produces +5VB, +15VB, and -15VB with current
from the mains transformer. Am I correct?
I believe so. I've never had an 11/34 with the battery backup option though.
My testing shows that I have the correct voltages on all the right pins,
including -15V. However, the LED on the H745 (-15V) does not light. What
does this mean?
The 'LED' runs straight off the output rail, so there's little that can
go wrong if the output is somewhere near -15V. Most likely you have one
of the older H745s with a light bulb not an LED, and the bulb has failed
(they do this from time to time ;-)). Or I suppose if you have an LED
that, or the series resistor, could be defective.
-tony