On 14/07/2014 02:22, Arfa Daily wrote:
For a long time, my primary printer has been an HP Photosmart series
all-in-one. It's a 6 ink job, which makes it expensive to replace inks
if you use the genuine HP article. So, for several years, I have been
using cheapo eBay inks. They come from China originally, and the most
recent ones I have been using, have translucent cases so you can even
see how much ink is actually in them. They are high capacity cartridges,
and the chip on them says so correctly. I have never had a problem with
the printer failing to recognise them as a high capacity cartridge of
the correct colour, and the usage indicator seems to remain accurate.

So, a couple of weeks ago, I come down in the morning, and it's sitting
there saying "copy abandoned", and the exclamation mark LED is flashing.
Sure enough, one of the missus's documents is in the top that she's
obviously been trying to copy before going to work. So I try the cancel
button - nothing. Nor the on / off button. No buttons work, so I pop the
power, just expecting to get the usual lashing for not turning it off
properly. But no. As soon as it gets going, it tells me that "The
following ink cartridges appear to be missing... " That would be all
six of them, then ...

Nothing would recover it from this. I had a trawl around on the net, and
there was a number of mentions of a couple of caps that bulge on the
main board, so I dived in to check, and yes ! there was one of them. I
checked its ESR for sport, and it was out the window. I stuck a new one
in, expecting all to be well, but it was just the same :-(

A friend lent me a printer in the meantime, while I had a think about
this one. Another friend is a pro photographer, and he has one of these
HPs also, and I knew that he only used genuine inks, so I rang him and
asked if he happened to have any empties laying about. He did, as he
takes them back to Staples, who give you half off in exchange. He came
over today with a bag of them, so I started by taking all of my
cartridges out. As expected, it told me that all of the cartridges were
missing, so I put in an empty colour one and restarted it. This time, it
told me that only five were missing, and the one that I had just put in
was nearly empty and should be replaced soon.

One by one, I added 'empty' genuine cartridges, and each time, it read
the cartridge ok. I eventually got to a full house, and all was well. So
one by one, I put my cheapo cartridges back in, and all remained ok,
until the very last one, dark magenta, when back came the message that
all six cartridges were missing. I went and got another from my stock
and put it in, and all was still ok.

I have actually seen the same symptoms with a brand new Canon printer
except that it was the genuine black cartridge that took the entire lot
down. I established this by trial and error after the cartridge OK leds
all went out unexpectedly when I put the black one in. I got a new
genuine black cartridge to make sure I didn't invalidate the warrantee
but it was a faulty supplied with the printer OEM cartridge.

So I'm guessing that the comms to these cartridges are just a simple 2
wire bus, and each colour just has its own address to allow the
processor to read them individually. I'm also guessing that the faulty
dark magenta cartridge, must have a short on one of the bus lines so
that when the processor issues the addresses in sequence to read each
cartridge at boot up, none of them are able to reply so the machine
assumes that they are not present.

How easy it would have been for the printer to have just got chucked in
the bin, for what was ultimately a simple problem ...

Not just HP where this sort of issue can arise. The first trick is to
take all the cartridges out and then insert them individually.

--
Regards,
Martin Brown