asked Oct 2, 2006 at 3:25am
Unknown Printer

Laserjet 5siMX - 50.1 fuser error

Hi folks,

I've had this 5si MX unit for several years, and just recently it decided to throw a "50.1 fuser error - cycle power" error. I purchased a "throwaway" 5si (not MX) for next to nowt, with the idea of swapping fusers - this I did, to no avail - I still get 50.1 fuser error".

I've now also swapped out the HV board & duplexer unit (just on the off-chance), with no change. I've tried swapping toner cartridges, which makes no difference either.

What should I try next?

Incidentally, the "throwaway" unit starts up without errors, although it won't actually print anything (it either paper jams, or prints blanks). I don't get any fuser errors in it, however, even if I use the fuser from my 5siMX.
You need to change the low voltage power supply for is located in the rear of the printer on the bottom.
by dmzcompute on Oct 2, 2006 at 5:22am Add comment

OK - I have now swapped, in addition to the above, the power supply & DC controller board - and both printers continue to exhibit the same symptoms...

I'm guessing that maybe I need to check the wiring harnesses now?

by unknown on Oct 3, 2006 at 12:58am Add comment
Now I've changed the wiring harness as well, and no change - I still get 50.1 fuser error.

So, now I am at a dead loss. I have absolutely no idea what to change next!

Any help gratefully received.

by unknown on Oct 3, 2006 at 2:49am Add comment
The only thing I have seen that causes that error is the fuser itself or the low voltage ps. I have never encountered a bad wiring harness. Are you sure you changed the low voltage ps. It is the piece at the bottom which has a fan on the left side when looking from the rear and you have to remove the fan in back by the right side when looking from the rear, the formatter, the small formatter plastic cover piece and the back cover in order to remove it. It has one wiring harness which threads thru the hv ps, and four pin connector on top to remove and a white connector which plugs into the dc controller.
by dmzcompute on Oct 3, 2006 at 2:57pm Add comment
Yes - definitely sure I replaced that bit (this is the long metal-cased unit into which the AC power connects, yes? Has wires going over the HV board to the top of the DC controller, also 2 smaller looms - a multicoloured job feeding the fan, and a white one also connected to the DC controller board).

I've also replaced the DC board, the HV board, the fuser loom (the bit that the fuser plugs into), plus the slot-in control board.

The printer resolutely refuses to get past the 50.1 fuser error; and the other printer (which I've been swapping bits with) resolutely refuses to actually print anything, although it doesn't report any errors.

Tomorrow, both are going to the tip I think... (minus the memory & Postscript ROMs)
by unknown on Oct 4, 2006 at 10:17am Add comment
Why not for the heck of it, move the laser/scanner from the one with the 50.1 error to the printer with blank pages. If it prints, then just move the PIU from the 50.1 printer to the one without error and maybe you will have a working printer. Keep in mind there is also the cable which runs from the low voltage ps to the fuser loom. If you just replaced the loom and not the cable, I would think you may want to change the cable first before anything else.
by dmzcompute on Oct 4, 2006 at 6:34pm Add comment
I considered that (moving the laser unit) - but I'm not sure how to get it out without damaging it and/or undoing about 100 screws...

Is it fairly easy to do?

by unknown on Oct 5, 2006 at 12:55am Add comment
To answer my own question... it was easy. Unfortunately - no change.

Thanks for all your help dmzcompute, but I think I've pretty much run out of things to check/change; so I will be replacing both printers with (hopefully) one which works...

by unknown on Oct 5, 2006 at 4:11am Add comment