HP 1055cm no magenta

[cscce]

After replacing the trailing cables and thoroughly cleaning the contacts on the carriage and on the printheads the self test indicated all printheads OK and full or nearly full. When the alignment page printed there was no magenta at all. Then an error code was displayed 0C0032 (drop detector not calibrated for all printheads.)

When I replaced just the magenta printhead there was still no magenta on the alignment page and the magenta and CYAN printheads indicated "monitor". Black and yellow still indicated OK.

With these weird symptoms and magenta never printing at all, even when status is OK, is this more likely a problem with the carriage or the electronics module?

All supplies installed are genuine HP.

Many thanks!

[Kiran Otter]

Re: HP 1055cm no magenta

Just curious; what did you clean the contacts with?

Did the issue with the magenta print head not firing exist before you replaced the trailing cable? If not, then I'd say you don't have the trailing cable seated correctly. It's very easy to get it wrong, and also easy to blow either the fuse or the main PCA if it's connected wrong.

If you did have this problem before replacing the trailing cable, then you may have a bad carriage.

Don't rule out having two bad magenta print heads.. it happens. Get a complete new set of print heads. Always rule out consumables first.

Run the Electronic Systems test; part of it tests the pen continuity and functionality. Follow the recommendations in the service manual if you get errors.

Kiran

[cscce]

Re: HP 1055cm no magenta

Just curious; what did you clean the contacts with?

Did the issue with the magenta print head not firing exist before you replaced the trailing cable? If not, then I'd say you don't have the trailing cable seated correctly. It's very easy to get it wrong, and also easy to blow either the fuse or the main PCA if it's connected wrong.

If you did have this problem before replacing the trailing cable, then you may have a bad carriage.

Don't rule out having two bad magenta print heads.. it happens. Get a complete new set of print heads. Always rule out consumables first.

Run the Electronic Systems test; part of it tests the pen continuity and functionality. Follow the recommendations in the service manual if you get errors.

Kiran

Thanks. I used an HP plotter maintenance kit to clean the contacts.
The problem before replacing the cables was the that magenta printhead was always flagged as faulty. This happened with 4 different magenta printheads.
At one point we installed a complete set of known good printheads from another machine. Magenta still flagged as faulty.
After replacing the trailing cables and cleaning contacts magenta comes up as either OK or Monitor, depending which magenta printhead is installed. But no matter which printhead is installed no ink ever comes out of the magenta printhead.
Previous tests of the electronics module indicated failure with 3 possible causes - carriage, cables or electronics module.
I haven't run the electronics module test since the cables were replaced and contacts cleaned. I'll run it again before proceeding.
Are there any connections on the carriage that might need to be re-seated (other than the trailing cables)?

I did see one post on the internet in which a cyan head was firing all the time, producing bands of cyan on every line. In that instance the main board was the problem. Although that is the opposite of my problem it could be a clue.

[Kiran Otter]

Re: HP 1055cm no magenta

Given what you've done, then I would agree it's the carriage assembly. Or, it's the main PCA, but I'd try the carriage first. If you're adventurous, you could try disassembling the carriage to reseat the flex cables.

And given the age of these printers, you can easily exceed the value of the entire machine while trying to repair it. I make my living repairing these printers but it reaches a point where it just doesn't make sense. I try to get owners to put the money towards either a new machine or something used like a 500 that can still be repaired.

Kiran

[cscce]

Re: HP 1055cm no magenta

Given what you've done, then I would agree it's the carriage assembly. Or, it's the main PCA, but I'd try the carriage first. If you're adventurous, you could try disassembling the carriage to reseat the flex cables.

And given the age of these printers, you can easily exceed the value of the entire machine while trying to repair it. I make my living repairing these printers but it reaches a point where it just doesn't make sense. I try to get owners to put the money towards either a new machine or something used like a 500 that can still be repaired.

Kiran

Thanks!
I'm the adventurous type so I'd like to take a shot at the flex cables. It's unclear to me how to pop the top off of the carriage to get to flex cable connections. Any advice?

Mike

[Kiran Otter]

Re: HP 1055cm no magenta

The top cover snaps onto the bottom half with tabs on either side. Just be careful you don't break it otherwise the trailing cable will rub against the top guide and cause a problem.

Beyond that, I don't really remember how it's all held together. I've never needed to take one apart.

Kiran

[cscce]

Re: HP 1055cm no magenta

Problem solved. It was the main board. Now there is just one more thing.
The main board I installed came from a retired 1055cm PLUS. The machine I've been working on is a 1055cm (not a Plus model).
The display starts out normal but after "End self test" and then ".." the entire display lights up. Looking at the display from an off angle I can make out the text on the screen.
On the Plus model the display looks fine.
So the question is - Is there a brightness adjustment or will I need to take the display from the plus machine in order to get the display to look right?
I haven't found a brightness adjustment in the service manual (but's then, it's not a "plus" manual, if that makes a difference).

Thanks,
Mike

[cscce]

Re: HP 1055cm no magenta

I think I just found it. It's in Utilities > Display Contrast. I was looking for brightness instead of contrast.
I'll know for sure tomorrow.

[Kiran Otter]

Re: HP 1055cm no magenta

Thanks for following up.. that's interesting that it was the main PCA. The only thing I'd note (and I could be wrong.. going by memory..) is that the two accessory slots are in different positions on the A vs B model (last character of the model number) boards (non-plus vs plus.) I think only one slot lines up with the rear cover if you put the B board in a A machine. If you just have a network card to install then it's not a big deal, but if you have the hard drive too...

I seem to remember going through this once and I had to get the cover (or entire EMOD) off a B printer, but ultimately it did work.

Kiran