Printer help?

From: Michael Sokolov <msokolov_at_ivan.Harhan.ORG>
Date: Thu Sep 9 15:19:56 2004

der Mouse <> wrote:

> Duh, I forgot to say: I've more than removed the dead cap.

Where was it? I thought it was on one of the PSU boards, but you now
seem to imply it's on the DC controller.

> Now, the power supply no longer does the tick-tick-tick overload thing;
> it comes on and stays on. But it doesn't work; I get the usual walking
> lights, then the 05 SELF TEST display, then SWITCHING TO PS; after a
> bit, it changes to 55 SERVICE.

The control panels lights and LCD are controlled by the formatter board.
That's the big one on the right, the one that memory and PostScript
options go onto and MIO cards and font cartridges go into, and the only
board in the entire printer that makes it an HP LaserJet IIISi as opposed to,
say, DEC LPS17. The fact that it walks the lights, enters the self-test
and knows about PS indicates that the formatted board is probably OK.

The formatter board talks to the DC controller, which is the main print
engine controller, which controls the entire Canon-built NX engine.
The formatter board throws up a 55 error if it can't talk to the DC
controller. If the board you are having woes with, the one damaged by
the blown cap, is indeed the DC controller board, then it's probably
the culprit.

The DC controller board is in the front right area of the printer, below
the control panel, directly behind the plastic front cover. If you take
a close look at the front cover between the tray openings and the font
cartridge slots, you'll see a small hole. This hole provides access to
the engine test button on the DC controller board. If you push this
button, the DC controller will print an engine test page independently
of the formatter, i.e., it'll forcibly override whatever the formatter
is directing it to do and will work even if the formatter is missing or
dead. Try it. But it looks like your problem is the opposite, good
formatter and bad DC controller.

> This may be because I still have all
> the covers off - there may be sensor switches

There are no sensor switches for the plastic covers. There are sensors
for fans and it'll halt if any fan is unplugged. The AC input assembly
in the PSU area has an interlock switch that cuts off the AC to the
fuser and the "B" side of +24V DC that powers the main motor, the laser,
and the high voltage supply for the imaging system if the top is lifted.
The "A" side of +24V DC that powers all logic is always on.

The only other interlock switches are the higher-level "top open" switch
that doesn't cut off any power, but tells the thing to stop and complain
about the open top on the LCD, and the EP cartridge presence detect switches.

> I think one of you said something about having a service manual; does
> it happen to say what 55 SERVICE means?

-- quoting: --
The "55 Service" error indicates that the printer failed to initialize
correctly at power ON. This means that the Formatter cannot
communicate with the engine in order to establish the initial
condition of the engine. This problem can be caused by a bad
Formatter, bad cable, or by problems with the line voltage. Check
and reseat connectors J4 and J5 on the DC Power Supply, and J8,
J9, and J10 on the DC Controller PCA. Cycle the power several
times to clear the error or to get another error that may better
indicate the cause of the problem. If this clears the error, run an
engine test print. If the error persists, replace the Paper Pickup
PCA, the DC Controller PCA, the DC Power Supply PCA, the
Formatter PCA. Finally, replace the Paper Input Unit. If these fail
to correct the problem, check all associated cables for damage and
replace if required. Any 57.1 Main Motor problem can also cause
this error.
-- end quote --

> Failing that, does anyone happen to have a spare board? It's the
> smaller of the two digital logic boards - the one that measures
> something like 6 by 8 inches, the one you have to remove the big one to
> get at.

I think you are talking about the DC controller board.

Someone just posted about having a bad HP 4SiMX for free for the taking.
He said it jams, so that's probably a mechanical problem and the
electronics is probably OK. He is in California (Bay Area), i.e.,
nowhere near you, but if you can convince him to take out and send you
the formatter and the DC controller boards, that might work for you.
You'll need both boards and the cable between them since it's a 4Si.
Since the two printers are otherwise identical, swapping those two
boards will turn your IIISi into a 4Si, i.e., you'll get 600 DPI and
PostScript Level 2. You might also need a few other bits like the
control panel (I'm not sure if they changed it), but nothing major
and certainly nothing heavy.

And if you two do work out that arrangement, I could take the rest
for spare parts next time I'm in the Bay Area. (I'm in Southern

Received on Thu Sep 09 2004 - 15:19:56 BST

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