HP LaserJet III-Error code 12 "Printer Open" problem

  • Thread starter Thread starter my machine
  • Start date Start date
M

my machine

This printer was just put into service 3 years ago although it was
made in 1990. It is new out of the box and has printed less than 1000
pages. When turned on it cycles through the self test and into the
printer open error. I have checked the obvious items including all
switches, DC voltage, most cable connections, ground connections and
have changed cartridges. I would scrap this machine except it is like
new, it's fast ,quite, and I have several extra cartridges. Anybody
have any ideas on fixing this problem?
 
HP LaserJet III-Error code 12 "Printer Open" problem

I have a III and a IIID and I would take a look at the cover interlock switch
to see if it is operating. The switch is just inside the cover opening on the
right front as you stand in front of the printer. Try operating the switch with
a match stick a few times.

Then with the cover closed try pushing on the cover right above the switch. If
this does not work you will probably have to adjust the cover switch.
If you are the type it might be prudent to acquire a used printer to practice
doing things like adjusting a switch. It will be rewarding.
Bob AZ
 
I have a III and a IIID and I would take a look at the cover interlock switch
to see if it is operating. The switch is just inside the cover opening on the
right front as you stand in front of the printer. Try operating the switch with
a match stick a few times.

Then with the cover closed try pushing on the cover right above the switch. If
this does not work you will probably have to adjust the cover switch.
If you are the type it might be prudent to acquire a used printer to practice
doing things like adjusting a switch. It will be rewarding.
Bob AZ
Click to expand...


Thanks for the reply.
There are several switches that are engaged when the top is closed.
After removing all the plastic enclosure parts, I was able hear each
switch (one at a time) actually engage as the cover was closed. Also I
have disassembled all the upper components and checked for continuity
and working of all the switches. I have verified that the two fans are
working properly. I have checked for the correct DC voltages at
various points. I have replaced a suspect capacitor on the media
density circuit board. I have tried every suggestion I could find on
HP's user forum. I hope to find another used laserjet III so I can
interchange parts to pinpoint the problem. Thanks again for your
input.
DEC
 
DEC
HP LaserJet III-Error code 12 "Printer Open" problem
Click to expand...

Thanks again for your input.

I can get you one cheap but the shipping could be a bear. But it is midnight
and I will sleep on the rest.

Bob AZ
 
me too ... did you find ?

my machine said:
This printer was just put into service 3 years ago although it was
made in 1990. It is new out of the box and has printed less than 1000
pages. When turned on it cycles through the self test and into the
printer open error. I have checked the obvious items including all
switches, DC voltage, most cable connections, ground connections and
have changed cartridges. I would scrap this machine except it is like
new, it's fast ,quite, and I have several extra cartridges. Anybody
have any ideas on fixing this problem?
Click to expand...

Today, I have exactly the same problem .. Did you find the source and how do you correct it ? or not !
I'm very interested if you have somethink about this...
My Printer give me this error code 12, five minutes after switch on... and my cover limit switch works properly... the other also.
The step motor try to turn few steps every ten seconds (produce noise) but nothing move...
Every help or ideas are Welcome...

Excuse my English... I'm better in French !

Jeannets
 
I found my Problem and my LaserJet HP III works properly now.... If you are interested, there is an other way that give the same Message "error 12"... blinking: The voltage level of the 5 volts to supply the processor card and logic circuits.

It was my case: 4,55 volts. for every TTL IC it must be 5 volts nominal..... Bla Bla Bla...

After 10 or 15 years it's possible because each component can drift.... May be more!

You can adjust this voltage to turn slowly RV2 pot. in the "DC power supply/ main motor driver module" front right side, see from the front pannel. This Pot. is visible from the biger square whole ... to the bottom...

Your Voltmeter show this voltage... GND= pin 7 and +5v=pin9 on the connector just under this unit; remove the retangular plate and look the 20 pins connector (for service ?) .... The pins are 1.3.5.7.9.11.13.15.17.19. bottom line, the N°1 on the left=+24v N°5=-5v N°7=GND N°9=+5v And discover you machine alive again !
If you are happy; send me an Email ...

jeannets
 
Back
Top