Philippe J Beaulieu wrote:
>
> In a message dated 12/6/98 2:58:36 PM Eastern Standard Time,
> [log in to unmask]
> writes:
>
> >  A new equivalent printer is not much
> >  more than the repair costs - but NOT a Canon.
> >
> This is really surprising to me as i have a canon bj-100 injet which is about
> four years old and has never been down even for a single day
> philippe beaulieu
>

And if I may add -- Canon support under warranty is great, while their
cost for repair out of warranty ar moderate.  I have a BJ-20 portable
(B&W) that has bounced around the world many times and it works like a
champ.  Someone mentioned an Epson.  Good printer BUT . . . the print
head is an integral part of the printer.  If it goes, so does the
printer (the cost to repair is equal to the cost of a new printer,
typically).  With Canon, just change the cartridge, because the
cartridge IS the print head.

Also, as someone previously commented, Canon is the manufacturer of the
engine in many (if not all) HP printers.  So while some people don't
like Canon, it really has a lot to offer and is typically a very good
printer.

BUT - look at prices for printers today.  They are like fancy toasters
or irons or even VCR's.  No longer worth the effort to repair because
the cost is almost or more than a new printer.

If you still want to try to fix it, you will need an oscilloscope and a
DVM (digital voltmeter).  You will have to get into the printer because
to attempt to troubleshoot near moving parts is asking for disaster.
This means you will have to remove the case to the printer without
disturbing the print mechanism.  You want to gain access to the printer
circuit card (actually, the other end of the flexible conductive plastic
strip that carries the signals to the printer) and to the centronics
connector that brings the print signals into the printer.

Cennector signals can be found on the WEB or at a library ( sorry, my
reference book is at work so I don't have the signal pin labels
available).

What to look for.  On the Centronics connector, check the 8 signal lines
for data pulses (zero to 5 volts).   Other lines may be constant HIGH or
LOW or may have pulses.  Look at the location where the conductive
plastic ribbon connects to the printed circuit card.  The Thick
conductive strips are for voltage and ground to power the printhead.
The smaller lines are the signal lines.  For the power, use the DVM to
measure the voltage.  Make sure the circuit card has power.  (You will
have to sort of search where the DC power comes into the card.  On
earlier units, the DC came from a wall brick.  Systems like the
4300/4400 have a plug in AC/DC pack that slips into the back, bottom of
the printer.)

If voltages are present (what is the right voltage?  for the circuit
card, probably not more that +5V.), they see if there is a location
where you can connect your 'scope to the signal lines going to the
plastic strip.  Check and see if there are pulses on these signal lines.

Since troubleshooting is a matter of elimination, if the print head is
not getting any pulses, but the data signals are coming into the circuit
board, you have two choices.  Get a replacement circuit board from some
where or get a new printer.

Since most boards now have application specific IC's on them, the era of
simple transistors and removable IC chips are long gone.

Didn't mean to bore anyone, but this is as close as you can get to
finding out what is wrong with it.

HTH
--
Jean Bourvic :>))

            PCBUILD maintains many useful files for download
              on our web site - visit our download page at:
                     http://nospin.com/pc/files.html