UNRESOLVED WORST TEST PRINT EXPERIENCED - ROLAND RF640

[Mark83]

Hi guys, just new here. Anyone who encountered this problem before, please share your knowledge what might be the cause and might the next step to do. This is a 4 months old print head and the attached image is the test print after done flushing the head. Done checking all the 4 head cables,trailing, linear encoder strip cleaning, fuses continuity check, linear and grit encoder sensor dry wiping/blowing, damper sucking. I'm confused what s the next step to do that might not create additional problem. Please, need HELP.

 

[player]

I had/have a similar thing going on with my VP540i. I am about to replace the mainboard.

How old is your machine?

 

[SignsSupport]

I don't have any resolution for your issue.
Just wanted to pop in and welcome you to Signs101. Feel free to 'formally' introduce yourself to the community via the New Member Introductions section.

SignsSupport

 

[Mark83]

2 years plus. Are you really sure that its the main board sir? Its kinda costly. Huuh!
Have you already tried replacing the head flex cables or the trailing cable and checked the fuses on the mainboard? Mine,fuses are okay. I wanted to replace the 4 head flex cables even if in my checking still has its continuity.but I find it hard here to buy some replacement of it. I already contacted the distributor of Roland here through email but until now havent got a response. from what country are you sir?

 

[Gene@mpls]

Sure looks electrical to me- is the machine well grounded? I don't imagine you have static electricity problems in the Philippines but the electronics can be sensitive to static and power fluctuations. I feel your panic, our RF has been making us a lot of money for 4.5 years and we would be in the sh!t if it crapped out. I sold the company and retired but if it was my money I was spending I would buy another RF while they are still made.

 

[player]

2 years plus. Are you really sure that its the main board sir? Its kinda costly. Huuh!
Have you already tried replacing the head flex cables or the trailing cable and checked the fuses on the mainboard? Mine,fuses are okay. I wanted to replace the 4 head flex cables even if in my checking still has its continuity.but I find it hard here to buy some replacement of it. I already contacted the distributor of Roland here through email but until now havent got a response. from what country are you sir?

I had intermittent issues. I changed the cables. Fuses don't cause that issue. It is tough to diagnose issues when one day the printer is fine, the next it craps out, the next it is fine again. But I don't know what else it could be...

 

[Mark83]

Hahaha, mr. Player I can relate it... there were some sort of excitement especially if we thought we already determined the cause and along with the solutions inside our mind, and suddenly after we did apply those solutions it becomes worst than the 1st one,& then again it s started to panic back again.huuuhahaha.

 

[Mark83]

If its a mainboard, y is it still capable of firing up I thought it s stil the same amount of ink s fired into the media? The difference is, it fires all colors simultaneously.

 

[Mark83]

Have you- aleeady tried checking the electronics board of the printhead?

 

[rjssigns]

I'd look at replacing the cables first. They are a consumable item.

 

[Solventinkjet]

The shot answer is basically you have a short in the print head signal somewhere.

The way this machine works is the CPU makes the signal that tells the head how to fire but it only outputs a 3 - 5 volt signal which isn't enough to get the piezo crystals to vibrate hard enough to push the ink out. So it has to go through an amplification circuit to up the voltage to what the head can use. Then the signal is sent to the head. When there is a short in the system, it mixes the signals between each channel which makes the signal essentially on all the time instead of a wave form that fluctuates. Another way to think of it is that instead of the Cyan receiving only the Cyan signal, it also get the black and magenta and yellow signal at the same time and vice versa for the other colors.

I would say more than half the time it's a dirty or damaged head cable or terminal. Usually I will check the cable and replace if it is damaged or dirty. I don't ever try to clean a dirty one because it might cause more issues and they are cheap to replace anyway. While I am checking the cable I also air dust the terminals it plugs into and then clean with 90% alcohol and then air dust again. Once everything is back together I test it out. If the problem persists, either the head is fried, the CR/Trailing Cables are broken, there is one or more transistor in the amplification circuit that is malfunctioning, and/or some other electrical issue in the machine. It's up to you to choose which way to go but usually I start with the trailing cables and work my way back. You can also sometimes get lucky and look at the transistors and one of them might actually have a burn mark on them. That would be the issue in that case.

 

[mr-blue]

Is the encoder strip clean and ok?

 

[Norman1987]

Is the encoder strip clean and ok?

This is no encoder strip fault.


Please recheck your every cable from head to backside into mainbord, i think is best if you change every cable. If this way isnt hep for you after next step was been mainboard.

 

[Mark83]

The shot answer is basically you have a short in the print head signal somewhere.

The way this machine works is the CPU makes the signal that tells the head how to fire but it only outputs a 3 - 5 volt signal which isn't enough to get the piezo crystals to vibrate hard enough to push the ink out. So it has to go through an amplification circuit to up the voltage to what the head can use. Then the signal is sent to the head. When there is a short in the system, it mixes the signals between each channel which makes the signal essentially on all the time instead of a wave form that fluctuates. Another way to think of it is that instead of the Cyan receiving only the Cyan signal, it also get the black and magenta and yellow signal at the same time and vice versa for the other colors.

I would say more than half the time it's a dirty or damaged head cable or terminal. Usually I will check the cable and replace if it is damaged or dirty. I don't ever try to clean a dirty one because it might cause more issues and they are cheap to replace anyway. While I am checking the cable I also air dust the terminals it plugs into and then clean with 90% alcohol and then air dust again. Once everything is back together I test it out. If the problem persists, either the head is fried, the CR/Trailing Cables are broken, there is one or more transistor in the amplification circuit that is malfunctioning, and/or some other electrical issue in the machine. It's up to you to choose which way to go but usually I start with the trailing cables and work my way back. You can also sometimes get lucky and look at the transistors and one of them might actually have a burn mark on them. That would be the issue in that case.

hi vander,thank you.
you are correct. it was a shorted circuit head board,its the reason that all colors were firing at the same time. I have much learning with this from you. thank you very much.

 

[Toks]

vanderbiltprint How did you fix the shorted circuit head board. Am having the same issue

 

[damonCA21]

vanderbiltprint How did you fix the shorted circuit head board. Am having the same issue

Have you fitted new head cables? Every time I have encountered a problem like this it is down to the cables rather than the head board. Anything on the board could be shorted though, so unless you know how to diagnose and repair PCBs would be easier to just replace the board with new or used

 

[Pub Concept]

Need help Roland RF-640
ink flows when cleaning but it does not print the test buses.
BIDIRECTION ADJUSTMENT: it only prints 2-4-6-8
I changed the dumper - ribon cable