4 Mar
2002
4 Mar
'02
7:06 a.m.
Hello all,
I'm very sad - finally my HP9845b is dead!
I'm beleaving, it's a problem with the power supply. Some years ago I
changed some capacitors already.
Does someone has or does kwow where to get schematics of the HP9845b?
Kind regards
Andreas
4 Mar
4 Mar
8:35 a.m.
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9:23 a.m.
The power supply in the 9845 isn't likely to resemble that in the 9825.
The 9845 PS is a shoe box sized unit that sits below and between the two
pillars that support the monitor. Inside it has one large circuit board and
four more circuit boards that plug into it around the edges so that it
resembles a box with an open top.
I just pulled out the dead one that I still had laying around here. It
has a number of test points on the top. One group of four with + 17 VDC,
-17 VDC, +13 VDC and Gnd 2. Another group of four with two of them plugged.
The reamining two are marked "C 18 175 VDC Max" across them. Then two
individaul ones on the top RH side that say 12 VDC and Logic Gnd. Below
them is five more in a zig zag pattern. They're marked +5 VDC, -12 VDC,
+18VDC, +7 VDC and - 18 VDC.
FWIW IIRC the other style didn't have test points on it but it seems to
be more reliable. I think all the ones of this style that I've seen have
had problems. This one has a large choke that's broken away from the board
and all of it's pins is broken off flush with it's housing. It could
probably be drilled out and the wires reconnected but I didn't bother since
I had other PSs. I don't know if this PS has any other problems.
Joe
At 10:35 PM 3/4/02 +0000, you wrote:
Hello all,
I'm very sad - finally my HP9845b is dead!
I'm beleaving, it's a problem with the power supply. Some years ago I
changed some capacitors already.
How similar is the PSU to that in the HP9825? I have a reasonable amount
of info on that machine.
In particular, what are the part number(s) on the PSU board(s). The first
5 digits normally give the machine where the board was first used, which
can be a help in tracking down info.
-tony
9:03 a.m.
Andreas,
I wish I did. I spent a couple of years looking for some. I did finally
find a service manual on E-bay but someone else sniped it at the last
second! I asked the buyer and he said that there were practically no
schematics in the manual. He also promised to make a copy of the manual for
me but never did.
FWIW I found that the 9845s had lots of poor connections. I was always
having to take mine apart and clean the contacts. I would advise investing
in a bottle of that expensive contact cleaner/preservative and see if it
helps.
Also there are at least two different power supplies used in the 9845B.
Joe
At 10:06 PM 3/4/02 +0100, you wrote:
Hello all,
I'm very sad - finally my HP9845b is dead!
I'm beleaving, it's a problem with the power supply. Some years ago I
changed some capacitors already.
Does someone has or does kwow where to get schematics of the HP9845b?
Kind regards
Andreas
8330
days inactive
8330
days old
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