Need Help My print head might not be firing...

[okeesignguy]

ok....my mag/yellow head has been perfect but my bk/cyan has had some banding issues lately so I thought with being kinda shut down right now would be a good time to install it and do some much needed maintenance...

I have done this twice before and am a mechanical type person with lots of tools etc...
I do all of my maintenance and parts replacement...

Yesterday I tore it down and did some clean and lube etc, replaced the scan motor and the dampers and wipers and the encoder strip as well...kind of a tune up...
I ran out of time yesterday so I came in to replace the head...

Anyway...here are some pics of where I was at this morning...
mag and yellow printing perfectly and bk and cyan crappy...



So changing the head was uneventful other than when I got it out I could see where it had puked ink so badly it was quite a chore to clean up the half coagulated ink of the plate and adapter...

So I did the head rank etc and got it all swapped out...aligned etc and proceeded doing a test print...

That's when I find that the mag and yellow were not printing at all...



So I did what I would normally do and ran a couple of heavy cleanings...nothing...
So I get out my trusty syringe and proceeded to pull the ink thru with it...never fails...
Run a test print and nothing...no mag...no yellow...

Knowing that I had a good solid draw of mag/yellow into my syringe I figured the head is not firing so I proceeded to check the ribbon cables...
All seemed fine but still, no mag/yellow...

At this point I figured maybe I pinched one of the cables or damaged it in some way so I swapped the cables from one head to the other fully expecting to see mag/yellow print but no bk/cyan...NOPE...
So...not the cables...

So this is where I'm at...
I know for sure there is ink there at the heads and I am sure the cables are good...
I even tried printing a set of two 1" x 40" stripes...one red and one yellow and nothing at all printed...

Obviously the head is not firing.....but why? That is the million dollar question

IDEAS anyone...??? Help would be greatly appreciated...

 

[Joe House]

The ink on the heads shorted out something. Hopefully a fuse, but imho, probably the printhead. You should have a couple of fuses on the main board. Check them with an Ohm meter to see if they're still good. If not replace the bad one. (Buy extras for troubleshooting at this point) If it blows again, then you're head is shorted out.
If they're both still good, your head is fried.

Good Luck

 

[okeesignguy]

The ink on the heads shorted out something. Hopefully a fuse, but imho, probably the printhead. You should have a couple of fuses on the main board. Check them with an Ohm meter to see if they're still good. If not replace the bad one. (Buy extras for troubleshooting at this point) If it blows again, then you're head is shorted out.
If they're both still good, your head is fried.

Good Luck

thanx man....I am leaning to that too but I don't know how I woulda done that...any ideas...?
I pulled the cover and as you can see there are only two fuses there...at lease under this cover...
Both in the left, lower corner...
I checked them and they are both good...
Are there others that I am not aware of...?

 

[Jim Hancock]

See attached pic for fuse location for print heads. One of them is probably blown. They are most likely soldered onto the board. There is also the possibility you have a blown output transistor. FYI, I have a PCB rework station and repair these boards to a certain level, i.e., fuses and output transistors. If you want to call me, I can walk you through checking the fuses and the transistors.

 

[okeesignguy]

See attached pic for fuse location for print heads. One of them is probably blown. They are most likely soldered onto the board. There is also the possibility you have a blown output transistor. FYI, I have a PCB rework station and repair these boards to a certain level, i.e., fuses and output transistors. If you want to call me, I can walk you through checking the fuses and the transistors.

Thanx man....I will check these for continuity in the morning...
Your area code indicates you are in Palm Beach...?
I am in Okeechobee....

 

[okeesignguy]

See attached pic for fuse location for print heads. One of them is probably blown. They are most likely soldered onto the board. There is also the possibility you have a blown output transistor. FYI, I have a PCB rework station and repair these boards to a certain level, i.e., fuses and output transistors. If you want to call me, I can walk you through checking the fuses and the transistors.

Is there a way to check the head itself...?
If I did in fact short something how would that happen...?
I was very careful...I even set the dampers (still attached to the tubes) directly into a baggie and worked with the power off...

 

[Jim Hancock]

I live in Delray Beach. What you did - the ribbon swapping - is the correct procedure to diagnose a good or bad head. I am presuming when you swapped ribbons, you moved left side to left side, etc. It would appear you have a bad head. But you need to check the board to be sure. The easiest way is to fire the new K/C head with both sets of ribbons, like you did to troubleshoot. If both sets of ribbons fire the K/C head, the board is good and the M/Y head doesn't fire with either one, that confirms a bad head and a good board at the same time.. As to what caused this, who knows? Sometimes s... happens. Let me know your results.

 

[okeesignguy]

I live in Delray Beach. What you did - the ribbon swapping - is the correct procedure to diagnose a good or bad head. I am presuming when you swapped ribbons, you moved left side to left side, etc. It would appear you have a bad head. But you need to check the board to be sure. The easiest way is to fire the new K/C head with both sets of ribbons, like you did to troubleshoot. If both sets of ribbons fire the K/C head, the board is good and the M/Y head doesn't fire with either one, that confirms a bad head and a good board at the same time.. As to what caused this, who knows? Sometimes s... happens. Let me know your results.

Yes I swapped both ends of both cables left to right and right to left...I did not cross anything over...completely removing them and using the cables on the opposite sides... I wanted to check the cables...nothing changed, telling me the cables are good...

I understand you to say to take the cables coming from the M/Y side of the board and plug them into the K/C head and visa versa...??? Like swapping the two sets on one end only...crossing them over...???

Where you confuse me is when you said "The easiest way is to fire the new K/C head with both sets of ribbons,"...
It sounds as tho you are saying to use BOTH sets of ribbons in one head at the same time although I am sure that is not what you mean...

I am headed to the shop soon and will try this...
Can I print with only one head plugged in at a time...?
Like trying both sides of the board, one at a time, using the new K/C head to eliminate a problem in the board(s)...?
Can I just leave the M/Y head unplugged while doing this and only wire the K/C head to the board...?

Thanx for your help, it IS appreciated...

 

[Jim Hancock]

Sorry for the confusion on the ribbons, long day yesterday troubleshooting an old Mimaki JV3 I am resurrecting.

To be clear, this is what I wanted to say. First, you want to do a test print with the ribbons in the correct position, i.e., as normal. Then shut down, unplug, and connect the ribbons from the K/C head to the M/Y head and vice-versa, without crisscrossing them. Then do another test print. If the K/C head still fires and the M/Y head doesn't, then the M/Y head is bad. If the M/Y head fires and the K/C head doesn't, then there is a problem with the board. You won't connect both sets of ribbons to one head, so sorry for not being clear.

The essence is you are going to drive each head first with the correct channel signal, then you will drive each head with the other channel. Think of it like switching left and right channels on a stereo to determine whether you have a bad speaker or a bad amplifier. Do not cross-over the ribbons on each head, as this will cause other issues.

"Can I print with only one head plugged in at a time...?
Like trying both sides of the board, one at a time, using the new K/C head to eliminate a problem in the board(s)...?
Can I just leave the M/Y head unplugged while doing this and only wire the K/C head to the board...?"

You should have both heads plugged in, as I believe the Roland printers obtain head temp info from the first channel, and you will probably get some kind of error if data from a print head is not received.

Once you get to your shop, please call to discuss and clarify before doing anything. I have done on the phone tech support for many years.

 

[MikePro]

resurrecting a JV3?!? need parts? lol, still sitting on my old machine and never got around to parting it out on ebay.

to the OP, just a thought before you dive-into fuses & electricals....
the main change from one day to the next, after replacing the damper/printheads was that your printheads stopped firing ink, but your printer is operating as it normally would?

if so, i'd lean-towards a cracked manifold. its the plastic tip of the printhead that plugs into the damper. happens a lot without noticing, too much pressure in either direction and it cracks, and could be inhibiting the flow of ink designed for a closed system.
data swapping could partially confirm this, or at least the location of the error being above/below the printhead, below the boards, etc.

 

[okeesignguy]

resurrecting a JV3?!? need parts? lol, still sitting on my old machine and never got around to parting it out on ebay.

to the OP, just a thought before you dive-into fuses & electricals....
the main change from one day to the next, after replacing the damper/printheads was that your printheads stopped firing ink, but your printer is operating as it normally would?

if so, i'd lean-towards a cracked manifold. its the plastic tip of the printhead that plugs into the damper. happens a lot without noticing, too much pressure in either direction and it cracks, and could be inhibiting the flow of ink designed for a closed system.
data swapping could partially confirm this, or at least the location of the error being above/below the printhead, below the boards, etc.

Thank you for your help/advice but we have it figured out...
The head is fine.....I have a blown fuse and we will be replacing it the first of the week...

 

[Jim Hancock]

resurrecting a JV3?!? need parts? lol, still sitting on my old machine and never got around to parting it out on ebay.

to the OP, just a thought before you dive-into fuses & electricals....
the main change from one day to the next, after replacing the damper/printheads was that your printheads stopped firing ink, but your printer is operating as it normally would?

if so, i'd lean-towards a cracked manifold. its the plastic tip of the printhead that plugs into the damper. happens a lot without noticing, too much pressure in either direction and it cracks, and could be inhibiting the flow of ink designed for a closed system.
data swapping could partially confirm this, or at least the location of the error being above/below the printhead, below the boards, etc.

Hi Mike,
The ribbon swapping shown above is exactly what I had him do. Blown fuse for the M/Y channel. He's getting the board to me to replace the fuse (solder on type) and check the transistors. I will save the pic, as it shows things much better than words, you know the cliché... Thanks for the input!

What model JV3 in case I need parts! What was its condition when shut down?

 

[MikePro]

What model JV3 in case I need parts! What was its condition when shut down?

will send PM with details for JV3-160SP.

 

[okeesignguy]

UPDATE.....Luckily I live fairly close to Jim and yesterday I drove the main board to him and he fixed it in a jiffy and for a very reasonable price as well...
Right now I am back up and running and it is printing as good as ever...
Thank you Jim...much appreciated...! Anybody in this area need printer work done...I highly recommend Jim