19 Jul
2006
19 Jul
'06
6:13 p.m.
Tony Duell wrote:
The *consumer* manual's big selling point is the description of
printing errors. E.g. "if the print anomaly occurs every
XXX inches, this is the cause; if YYY inches, that is the cause;
etc. It also helps with part numbers for replacements (which,
I believe, the OP was seeking).
I think it also lists signals (i.e. supplies) available at each of
the various connectors in the machine. For some reason, these
printers had lots of *cable* problems (I suspect the problems
were in the *connectors* on the cables)
Hi,
I've got a Laserjet III that's intermittently throwing Service 50 errors.
Fusing lamp tests good as per
<http://www.fixyourownprinter.com/reference/guides/fuser/sx>. I assume this
means the AC power module has fried itself.
It might do. It might be a lot of other things too.
I'll give a basic overview of what goes on in the various modules, I can
dig out the schematics (which are not in the HP service manual, this is a
somewhat useless document, therefore!), if you want to go further. 3) A circuit to cotnrol the cooling fan that you can
ignore for the moment.
I have a note about replacing the "upper fan" in an LJ3 with
this type of problem. So, I expect they are related -- if only
indirectly (perhaps loading down a supply when faulty?
I'd have to check if the thermistor is PTC or NTC to see
how that might confuse the MCU)
I once had a particularly nasty fault there. The relay
would turn off a
few seconds after power-up. It even did it when I powered the module from
a 24V bench supply (and with no pulse input at all). Every associated
component tested fine. It turned out that one of the electrolytics had
leaked slightly and put a conductive gunge on the PCB. This was providing
enough current to trip the protection circuit (!).
I had a similar experience with a Lexmark Optra Se3455 (?).
Except it caused the expansion PCI bus to malfunction so
that the NIC wasn't reliably seen. Weird. I suspect the
bus must have been buffered since it didn't interfere with
the rest of the devices operation.
--don