Help 1 Channel DX6 not firing Vs540i

[Adam Edge]

Hi guys,

My dual CMYK vs540i only 7 colours firing. Magenta on far right will not fire at all. it's not damper or ink issue. I've checked all that. Could it be Carraige board or the printhead? I may have had ink spill on printhead duing damper change. Is it commond for head to go bad by not firing only 1 channel? or Carraige board is a common issue with a problm like this?

 

[damonCA21]

It could be the head, but it is unusual for only one channel not to fire, you will normally get problems with more of them.

If you are getting ink to the head, then it could be the print carriage board. They can go faulty and cause problems like this as they will stop sending the signal to the magenta channel. If it was working fine before and just randomly stopped then it is more likely a board problem than the head.
I would look at replacing that first and see if it solves the problem

 

[Adam Edge]

It could be the head, but it is unusual for only one channel not to fire, you will normally get problems with more of them.

If you are getting ink to the head, then it could be the print carriage board. They can go faulty and cause problems like this as they will stop sending the signal to the magenta channel. If it was working fine before and just randomly stopped then it is more likely a board problem than the head.
I would look at replacing that first and see if it solves the problem

thank you for replaying. is there a way to diagnose the Carraige board? usally fuse and mosfets go bad on mainboard and ive been able to diagnose the faulty part and replace it. CAn i take a multimeter to it?

 

[damonCA21]

Not very easily, but it depends what the problem with it is. There aren't any fuses or transistors on the print carriage board, so it is more likely one of the chips on it has failed. If you can get the schematic for the board you can go through and test things if you know what you are doing, but if you short things on there you can cause more damage

 

[damonCA21]

It is probably worth checking your mainboard transistors as well just to make sure they are ok, as if one has blown then that will stop printing on that channel

 

[Adam Edge]

yeah i didnt check mosfets/transistors bcaz usually even if 1 fails the whole head stops firing or half of the channel. never had just 1 colour stop firing

 

[damonCA21]

Yes, that is why I am thinking its more likely to be the carriage board in this case. Normally the transistors failing is from a short when someone has unplugged head cables without the printer being powered down completely

 

[damonCA21]

To test the carriage board though you really need to do it while the printer is running and have an oscilloscope. A multimeter won't be good enough to pick up the signals to the head

 

[Adam Edge]

To test the carriage board though you really need to do it while the printer is running and have an oscilloscope. A multimeter won't be good enough to pick up the signals to the head

yeah damn, im not that pro of a tech! ill order new board and post the outcome. thank you again for your help!!

 

[damonCA21]

yeah it is quite fiddly trying to diagnose them to that level. If you are getting a new board, avoid the chinese sellers selling cheap copy boards, try and get a used OEM Roland board. If the chinese copies work at all, they are unlikely to work properly and could cause more damage to the printer

 

[Adam Edge]

yeah it is quite fiddly trying to diagnose them to that level. If you are getting a new board, avoid the chinese sellers selling cheap copy boards, try and get a used OEM Roland board. If the chinese copies work at all, they are unlikely to work properly and could cause more damage to the printer

installed new board and ribbon cables. Did not fix the problem. I'm starting to think head is gone

 

[Adam Edge]

update: head was shorted. (note to self, do not touch printhead while machine is powered on and printing) only 8th channel was not working. Lucky I was able to convert it to 7 colour machine which doesn't need 8th, far right one. Over 1 a year since, still running good.