21 Jul
2006
21 Jul
'06
4:12 p.m.
My first laser
printer used a Canon CX engine. I was given it because it
didn't work, it took me an hour or so to find a dead PAL (actually a HAL)
on the formatter board. Canon didn't sell spare chips, they wouldn't even
sell be the complete board. And they wouldn't supply a service manual.
(This was before I'd found The PrinterWorks, who would at least sell
mechanical bits and complete boards).
Oh, you are the one of the CX crazy printer, you are a god! :oD Many of the laser printer repair books and stuff
on the web are
downright wrong. Others simply encourage lucky-dip methods. I've yet to
see one that really goes back to first principles and tells you to start
by checking signals, etc.
Well, this is a deeper level that me and you may understand, but what
about the John Doe with error 50 on his HP3? I fixed **lots** of HP3 with just changing that (insert your preffered expletive
here) thiristor, and
giving a good cleaning and resolder of contacts as I stated in my part of
the text
Oh, agreed. If I have an error 50, I pull the fuser and check the
resistance between the pins of the 2 pin connector. Because about 75% of
the time, the lamp is open.
But if that doesn't work, I grab the test gear and look, first, at the
signals on the protection board (easy to get to, just remove the casing,
upper fan, and cover on the AC block). Then I can see if (a) the DC
controller should be driving the fuser and (b) if the protection board is
driving the opto-triac and relay correcly. That gives be the direction to
look in for the next fault.
-tony