Question What happens when a head cable gets pulled out when powered on

[sidcon]

Hello, I have a question on what happens or what damage can accrue if a head cable is pulled out and reconnected while the machine is on. One of my guys finally admitted to doing this and I think is the cause of our no print issue with our VS640.

 

[Solventinkjet]

It blows a fuse that causes the head to stop firing. It's on the main board near where the long cables that come from the slider board to the main board connect. I haven't had a chance to get the rating for that fuse yet but a lot of DX7 head machines use the 750mA fuses.

 

[sidcon]

thank you for the reply. we checked F1 and F2 head fuses and the main fuses and all check out good.

 

[FrankW]

Other components on the mainboard can be killed too.

 

[Solventinkjet]

thank you for the reply. we checked F1 and F2 head fuses and the main fuses and all check out good.

I have seen a couple fuses test positive while they are in the machine and then not when they are out of the machine so that could be the case. But if the fuses are good and you know for sure ink is flowing through the head during a cleaning cycle and the head still prints nothing, one of the components on the head have blown. Unfortunately, there isn't a lot of knowledge on the head components and I haven't had a chance to test anything out personally. Usually in that case the head needs to be replaced. I would say in my 10 years experience as a tech, when there is a short like when you pull the cables out and the power is on, at least 99% of the time the fuse on the main board blows and the other 1% the head fries.

 

[sidcon]

Thank you for the replys. Ink is defiantly flowing thru the head, I will pull the fuses and recheck. I want to ad that my guy said the sub power was off but the main power was still on. He saw a leak where the ink lines enter the damper and some of the ink got on the connectors of the head.

 

[Solventinkjet]

Thank you for the replys. I want to ad that my guy said the sub power was off but then mail power was still on. He saw a leak where the ink lines enter the damper and some of the ink got on the connectors if the head.

You can do damage even when the printer is unplugged. Tell him next time if he wants to work on the machine he needs to turn it off, unplug it, hit the power buttons a couple times and wait 15 minutes. You might be lucky and just need to clean the connectors with 90% alcohol. If the ink got on the cable leads, I would just replace the cables. After getting ink on them, even if you clean it off, it can cause damage to the cable and it will just keep popping fuses.

 

[sidcon]

Thank you very much for all the info, The ink got in cable sockets where the cables plug into the head.

 

[sidcon]

The fuses Checked out good out of the board, I cleaned the cable leads and sockets with alcohol after this happened pretty good. what would be the chances of the print carriage board being possibly damaged? To be honest Im not sure what that board even does. Im going to order up some new cables now and pray its just that. Then will try a new head. Is just the circuits on the head able to be replaced? Thank you again for all the info

 

[Solventinkjet]

The fuses Checked out good out of the board, I cleaned the cable leads and sockets with alcohol after this happened pretty good. what would be the chances of the print carriage board being possibly damaged? To be honest Im not sure what that board even does. Im going to order up some new cables now and pray its just that. Then will try a new head. Is just the circuits on the head able to be replaced? Thank you again for all the info

You brought up a good point. On some of the more recent models there is another fuse on the carriage board also known as a slider board. In general though slider boards don't normally go bad as they are closer to a junction board than having any real functions. That being said it can go bad so don't rule it out. You can't replace the circuits on the head but you could try to replace certain components like capacitors and resistors etc. As I said above though, I have never heard of someone fixing a head by replacing components on the head itself before.

 

[sidcon]

Thank you for all the advise. I have a bad feeling with everything you said its the head because all colors are out not just one, if was a cable then maybe just that color would be out. I will also look into the board, I didnt see any fuse on it.

 

[sidcon]

Oh, something else weird to ad, it won't print any nozzle in a test print but it will print a report in service menu. Not sure if that would help in any other last thoughts. It also will print very very faded if trying to print something.

 

[sidcon]

Had some time this weekend to pull the head and inspect it. This is what I found, from a leaking damper. I thought I would have gotten a low temp code if the head was fried but it still had signal to the board. This ink would defiantly fry it right?