Laserjet 4 motor problem

[David1012]

How to dismantle and identify the problem 

57 Service is the code which it carries out a Self Test

[Imagecomputer]

Hi.

A what?  A LaserJet 4?  Nice!

Ok.  Here's what you do.  The main motor on this machine isn't too bad to get at.  It's on the right hand side, behind the formatter board.  The formatter is held on by about 6 screws (a couple in the rear, and the rest around the perimeter).  If you're standing facing the right hand side of the machine, the formatter will pull straight toward you (you might have to wiggle it a little; it can be slightly tight).  The main motor is right behind that. A couple things to think about:

A 57 error CAN be caused by a bad main motor, but it can ALSO be caused by something else binding/sticking in the gear train.  These things include: the toner cartridge (92298A), the fuser (RG5-0454-000CN), and the drive gear assy (RG5-0457-000CN) are the most likely culprits.  If you've determined that the main motor is the bad part, the part number is: RH7-1152-000CN

Good Luck!

Matt

Image Computer Corporation

[David1012]

Hi Matt, you already have been most helpful!  As you can gather I am an aged Newbie and very much appreciate your instant response!

I have now got the machine, to a degree, dismantled in that I am looking at the housing within which is the simm housing with one simm card present and I understand the  panel is called the Formatter board.

I understand that the motor housing is behind this board with  and am slightly perplexed as to which screws one should remove to remove the formatter board.

Woutd it involve disturbing the main on/off switch which appears to be below it?

With the motor train removed this will allow me to inspect the gear wheels for possible damage.

Is there a technique to prove the viability of the motor?  I have a simple digital multimeter!

Once again many thanks!

David1012