50 Service Error

[Takamine]

HP LaserJet 4MV. Getting a 50 service arror. Is there any way to determine if the problem is in the fusing unit or the power supply? Also, is there an easy way to remove the main power supply, I can't figure it out.

Thanks

Rich

[kalboako]

Try to change the fuser assy first before power supply.

ric

[woodss]

sometimes the power supply can cook the fuser unit, remember that.
even bad DC controllers can do that too.

[Takamine]

Here's what's happening.

Printer runs for a while, then we get a 50 service error.
Turn the printer off, let it set 20 minutes, turn it on.
Printer runs for a while, then we get a 50 service error.
Turn the printer off, let it set 20 minutes, turn it on.
etc . . .

I swapped the fusing unit with an old one and it does the same thing. However, that fusing unit is old and may not be up to par either.

If a power supply was bad, would it work part of the time?

Thanks
Rich

[jim]

The low-voltage power supply replacement requires quite a bit of disassembly. You will need to remove the upper,right,left and rear panels. Next will be the removal of the formatter, followed by the DC controller, then the metal support bracket, and finally the power supply itself. It can be a difficult job, you may want to reference the service manual for photographs and call-outs. Hope this helps, Jim