Designjet T 2500 strange issue carriage slams and repeats last print

[juanT2500]

Hello all. I've been figthing this problem for 6 months now, I have tried everything I can think of to no avail.

Designjet T 2500 with very weird issue. When the last job in the print queue finishes printing, the carriage slams against the left side stop (svs side) and then repeats the last print. No error code or message is displayed. The same thing happens on startup cycle and cleaning cycles. The problem developed gradually. First it happened once a month, then once a week, now it happens every single time. I can't find anyone having a similar issue in the forums.

This is the same problem of my previous post, where I (incorrectly) diagnosed a problem with the line sensor because the line sensor calibration failed with error. Alas, the problem is not in the line sensor. The problem is in the routine the printer runs when it finishes printing, whatever that print was.

I posted a video of the problem on the following link. https://www.youtube.com/watch?v=pCud1CcvU1M

You can see in the video: 1 print first copy (the print job is one copy of course), 2 slam!!, 3 print second (unwanted) copy, 4. the carriage now parks normally. Sometimes, the same procedure repeats more than once, and I get 2, 3, or even 4 copies, until the carriage parks.

I have replaced the following:

SVS station, with new drop sensor (was at the end of life anyway...)

Encoder strip

Belt with tensioner

Line sensor

Carriage PCA

Notes:

The carriage movement is not obstructed

The rail was cleaned and lubricated thorougly

Firmware IS updated

Scan axis diagnostic test reports no error

I performed the service calibrations. They all proceed ok, except the ones that consist of printing something (like the line sensor calibration), in those, i get the same symptoms: print, slam!, and abort test.

[Repairatrooper]

It is almost like it is loosing track of the position on the encoder strip. Have you checked all the leds on the main boards to ensure there are no errors there?

[styloid]

What an interesting problem.

My guess is it's ink system related.

Its printing ok then abandons the print as if some ink error has occurred.

I'd start with the cartridges.

Remove the base plate and check if the black rubber bit is not squidgy. This is caused by air. If so get a needle and syringe and remove the air.

I'd then replace the printhead. Or you can take the head to bits and examine the intermediate cartridge for ink levels. 

I don't think they should be full, but they should not be empty either. You can inject ink through the port.

Heads are a bit costly but messing about with them is tedious and results uncertain.

If none of this works I'd try another set of cartridges.

There is other stuff to try but with less expectation of success. See how you get on with this.

Regards

Bristol inkjet

[Valsimot]

Trailing cable connecting carriage PCA with main PCA could be losing connection.

[juanT2500]

Thanks all. Will try all 3 suggestions today an dreport back. Please note that in the video I was sending just a small test print. Just that little bit of a cad drawing. Its not that the printer stops mid-job. That was the whole print job I was sending.

[juanT2500]

Well, here i am.

Regarding the indicator leds in the electronic boards. As far as I can tell, they are all normal. Although the service manual "could" be a little more clear in this regard. After performing a fresh reboot. I get: three lit solid on the formatter board, two lit solid on the carriage pca, and my psu unit has no led, weird, it came like that from the factory. The plastic cover has the hole where the psu led should be, but there's nothing there...

Regarding the cartridges, I checked the rubber "button/pump/bellows" or whatever is called... on all six colors. They all feel fine to me, nice and solid. I tried inserting a syringe needle in the outlet port and when I press the rubber thing, a geyser of ink flies all over the place... it looks like that they are putting out pressure just fine. Regardless, this issue began years ago, albeit very sporadically... it grew worse over time....and along that period, a lot of ink cartridges and printheads passed through the printer. I didn't notice any correlation between cartridge change or printhead change and this issue getting better or worse.

Regarding the trailing cable connections. When trying to diagnose this issue, I ordered a new carriage pca and replaced it. In so doing, the trailing cable connection was reseated, at least at the carriage end. The other end, where it plugs into the engine pca, I haven't checked, although I could if you think it's a possible solution. 

I do think this is somehow drop detector related. Here's why.  In the video, you can see that, after printing, the carriage moves to the left (and slams)... but when it parks succesfully, it moves to the RIGHT a little bit, and carries out some sort of procedure.. and then parks. I think that's the drop detector doing a quick drop check. Although I dont see how it could be a drop detector failure because 1. it is brand new and 2. the dro detector calibration completes succesfully, with all the values in range.

[juanT2500]

Since my last post I have discovered that if I disable the queue, I can stop the printer from repeating the last print, so i can avoid the nuisance of wasting ink and media. The problem, however, remains. After printing instead of parking the carriage it slams it to the left, and the printer goes into a "vegetable state" for a few seconds. There is some after-print routine that is going haywire.

[juanT2500]

I'm looking at replacing one of the main boards to fix this issue. Can someone knowledgeable in designjet printers chime in about wether its likely that the problem resides in the main engine pca or in the formatter pca?

[juanT2500]

I t would seem that this problem has been resolved. APPARENTLY it was a bad printhead. I has been running fine for two days now. I will report back in a week or so to confirm that the problem hasn't returned.

[D Hook]

Thanks for following up with what you've found.  Hope that's all it was.