[sci.electronics] Help on BDS laser printer

dave@ips.oz.au (Dave Horsfall) (06/24/91)

[ I'd use comp.laser-printers, but it hasn't had a message in it for ages ]

I am the ex-proud possessor of a "BDS Lazertron 8" printer (well, that's what
it says on the front).  Its history is unknown, I bought it 2nd-hand, and the
distributor has long since gone out of business.  After years of sterling
service, it is now behaving in an odd manner.  First, a brief description is
in order.

It is Canon-based, and takes the same fusing rollers, cartridge, trays etc
as does the Apple Laserwriter.  Naturally, Apple dealers don't want to know
about it, apart from selling me spares.  A sticker on the side says: "LBP-CX
I/F PCB-1", with some sort of stylised logo consisting of the letters "GS"
tracing out the paper path.  The manual says it is a "BDS Laser 630/8", dated
Jun 24, 1985.  It emulates Diablo 630, and claims to do HP LaserJet, but it
is not documented, and I've never figured it out, although I do get some
weird graphics when my WordStar jobs get out of hand.  BDS Australia went out
of business a long time ago, as did the people that took them over.

Now, the problem.  It is best described as "loss of memory", in a funny sort
of way.  If there is an appreciable interval since printing the last page,
such as power-on after a while, or a dense page taking a long time to image,
the thing starts to feed the next sheet, then instead of a loud "CLUNK" there
is a quiet "click" instead.  At this point the display signals a paper jam,
and the errant paper is found in the pre-feed somewhere.  After extracting
the sheet (and power-cycling it, since there appears to be no other way of
resetting it) it can take MANY cycles like this before it comes good.

As luck would have it, I discovered another way - remove the paper tray,
power off for a while, power on, then if I am in luck the stuck sheet will
start feeding through.  If I'm really in luck the printer is then ready
to start printing as normal.

However, it varies.  Indeed, the problem seems to slowly get worse, but
once it actually starts printing, it sorts of "remembers" that it is OK
to print - i.e. delays that would have frozen it earlier in the power on/off
cycle no longer worry it, that is, until there is a VERY long delay between
pages (such as setting up a new print run etc).  The problem is difficult
to describe, but you get the picture, I hope.

It looks suspiciously like the EEPROM is failing, after all these years
(and cycles).  So, what sort of an EEPROM would it use, if this diagnosis
is correct?  Where would I even FIND the EEPROM within its innards?  I'm
understandably reluctant to pull a laser-printer apart...

Has anyone even seen one of these dinosaurs before?

-- 
Dave Horsfall (VK2KFU)         VK2KFU @ VK2RWI.NSW.AUS.OC
dave@ips.OZ.AU                  ...munnari!ips.OZ.AU!dave