[Electrical] Tips on replacing a TPH unit in a Riso MZ790U

[Guest]

Hello all

The thermal head in my Riso MZ790U recently started playing up. The machine has been making prints with a 5mm band
of information missing in the middle of the paper (see attached image). I've tried resetting the machine and cleaning the
TPH - but neither helped solve the problem.

So, I am going to replace the TPH unit in the MZ - but I wonder if anyone here could give me some pointers on things to watch
for/be careful about when doing this. I understand that I will need to adjust the ohms when I install the new unit - anyone
have any ideas about how to do this?

Any help would be much appreciated!!

best

Duncan

[Iowatech]

Re: Tips on replacing a TPH unit in a Riso MZ790U

I haven't replaced a thermal head on the MZ line, so take this for what it is worth.
Still, every other time I've replaced a thermal head the specs for adjusting it were in the documentation that accompanied the replacement thermal head. The last time I replaced a thermal head it was on a label on the thermal head itself.
On the other hand, the thermal head is pretty much the most expensive part on a Riso, so replacing it should not be done on a whim. Have you checked that there isn't something on the drum that is causing that print defect?

[NeoMatrix]

Re: Tips on replacing a TPH unit in a Riso MZ790U

Is the problem the same with a different drum unit ass'y?

[thecopierdude]

Re: Tips on replacing a TPH unit in a Riso MZ790U

I can send you the Thermal Head ASSY from a used machine for $550 & send instructions for OHM change. Paypal to thecopierdude@Hotmail.com gets it shipped