I tested the wall outlet. It reads 125v. I used a ground tester and
I can confirm the unit is getting a proper ground (which takes
another undiscussed possibility out of the equation)
To clarify, my H7441 bricks do indeed light up at least, and when
they are on, testing the +15v lines from the open H754 connector
yields the proper 14,9-15.1 volts, so those are definitely working OK
when not under load.
Another thought is, my AC input box is marked by DEC as being 120V.
Could this have been adjusted for 220V, and if so, how would I be
able to tell?
On May 11, 2006, at 2:18 AM, Gooijen, Henk wrote:
Hi Julian,
without looking at the diagram (I am at work now).
True, the incoming *AC* voltage to the power bricks is some 22 V.
I assume that P1 is the Molex connector that has (IIRC) 8 black
wires which are 4 2-wire groups of the AC supply to the 4 bricks.
In that case, measuring 10 to 15 Volt (AC) is rather low.
The H744 (25A) or H7442 (32A) 5V bricks should work at 10-15 VAC
input, but what will the AC input voltage do under load condition?
Is the mains input voltage correct (what you get from the wall
outlet). Careful! Does that match the spec of the PSU?
- Henk.
-----Original Message-----
From: cctalk-bounces at
classiccmp.org
[mailto:cctalk-bounces at
classiccmp.org] On Behalf Of Julian Wolfe
Sent: donderdag 11 mei 2006 8:41
To: General Discussion: On-Topic and Off-Topic Posts
Subject: BA11-K low AC output levels
Okay, so, I'm back to working on my /34. I think I made
significant progress tonight.
What's going on is, I've narrowed it down to low AC levels
coming off the transformer. The printset and H7xx modules
specify an incoming AC of 20-30v (printset says specifically
28v.) All lines coming off the transformer at P1 are reading
a value of 10-15v.
So that leaves two possibilities. It's either the
transformer, or the AC input box.
I'd like to test the levels coming out of the input box, but
I wouldn't know where to go, as my understanding of
electronics fades fast at this time of the night when I've
been up since 07:00.
Okay, so maybe I traced it back that far, it got more
complicated, and it's late and I'm feeling lazy and hoping
someone will throw me a bone here :) in any case, advice is
always appreciated.
toodles
Julian
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