Need Help SP-540v Printhead Issue Blowing Fuse

Nate.H

New Member
Hi there, I'm new to the forum, but I've come across it a lot through my troubleshooting ventures, so I'm hoping the lovely folks here in the Sign101 community can help me. I have some basic electrical experience and soldering skills, but I'm not 100% confident where to look next with this particular issue.

The Issue:
I have a VersaCamm SP-540v that, I believe, has a short-circuit or some other electrical issue. About a year ago, the printhead fuses both blew. I was able to replace them and it's been working fine until just last week when they blew again. This issue was made evident when it began printing only black and blue ink.

I replaced the fuses again, but when I ran the test print, it went back to only black and blue. After investigating further, I saw that one of the new fuses had blown again (the one on the left in slot F3). From what I've gathered from online forums, I believe it may be related to a short circuit maybe in the printhead or somewhere in that area. Before purchasing the $700 printhead, I want to make sure (with your help) that the printhead is, indeed, the issue and it's not something else.

Troubleshooting Steps I've Performed:
  • Tried replacing the fuses, but that resulted in another blown fuse.
  • I've checked all 4 ribbon cables connected to the printheads for continuity and they are all working properly.
  • I checked the transistors because I read somewhere that they may be the source of similar electrical issues. I'm not entirely sure how to check the transistors, but I did notice that the C4131 transistor which is second to the left on top was returning an open connection between the two sides (I assume Emitter to Collector), where all other transistors return around 40 when connecting the two sides.
I have another Roland printer (SP-540i) that I could try swapping some parts for troubleshooting (assuming the printheads are the same type), but I'm hesitant to do that since that's our only working printer at the moment. I'd hate for one of those parts to break in the process.

Can you offer any advice for troubleshooting this issue and identifying the parts that needs to be replaced?

Thanks,
Nate
 

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Nate,

To be clear, you are reading 0 ohms on the transistor circled in the picture, correct? If so, that is a short, not an open, and will continue to blow the fuses until it is replaced. Once it and the fuse are replaced, you will be able to determine if the printhead is ok. If the fuse blows again after replacing both, than you most likely have a bad head. If you cannot repair the board, or have someone who can, that is a service I offer.
 

Nate.H

New Member
Nate,

To be clear, you are reading 0 ohms on the transistor circled in the picture, correct? If so, that is a short, not an open, and will continue to blow the fuses until it is replaced. Once it and the fuse are replaced, you will be able to determine if the printhead is ok. If the fuse blows again after replacing both, than you most likely have a bad head. If you cannot repair the board, or have someone who can, that is a service I offer.

Ah yes, thanks for the clarification, I’m still learning :)

And thank you for confirming the short in the transistor. I’ll replace the transistor and fuse and see what happens.
 

Nate.H

New Member
How did your repair go?

Hey Jim (and anyone who's reading this). I was able to replace the transistor as well as the blown fuses. I ran into some delivery issues, which is why it's taken so long. I've run a test print, but I'm still only seeing black and blue ink. I've verified that the transistors and fuses are still good after this test print was performed. What would be my next step in finding the part responsible for this issue?
 

Solventinkjet

DIY Printer Fixing Guide
Do a data swap. Basically unplug the head cables from the heads only and swap them so the black.cyan head is getting the magenta/yellow signal and vice versa. If the black and cyan head still fires and the magenta yellow one doesn't, the head is fried. If the black cyan stops printing and magenta and yellow do, it's more likely another board issue deeper in the machine.
 

Pine

New Member
If both heads are firing, as Solveninkjet's suggestion, revisit the transistor board again and check other components (resistors, caps etc) around the damaged transistor....
 

Nate.H

New Member
Do a data swap. Basically unplug the head cables from the heads only and swap them so the black.cyan head is getting the magenta/yellow signal and vice versa. If the black and cyan head still fires and the magenta yellow one doesn't, the head is fried. If the black cyan stops printing and magenta and yellow do, it's more likely another board issue deeper in the machine.

I swapped the cables and, as shown in the attached image, the black and cyan still print, except one space to the left. I'm assuming this means they're printing in the place that normally Yellow and Magenta would print. So I guess at this point it's safe to say the print head needs to be replaced.
 

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Nate,
It would appear your magenta/yellow head is likely bad. The test prints are a little confusing. You only need to swap the cables in one way. Please do a new test print with the cables in the correct position, then a second test with the cables swapped as follows: 1&2 on carriage board to 3&4 on print head (M/Y), and 3&4 on carriage board to 1&2 on print head (K/C). Please mark as original and swapped. I know you swapped the cables, but the test print spacing isn't what I normally see when doing this. Just want to be sure before confirming you have a bad head. I'm presuming the transistors and fuses are still good.
 
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Nate.H

New Member
Nate,
It would appear your magenta/yellow head is likely bad. The test prints are a little confusing. You only need to swap the cables in one way. Please do a new test print with the cables in the correct position, then a second test with the cables swapped as follows: 1&2 on carriage board to 3&4 on print head (M/Y), and 3&4 on carriage board to 1&2 on print head (K/C). Please mark as original and swapped. I know you swapped the cables, but the test print spacing isn't what I normally see when doing this. Just want to be sure before confirming you have a bad head. I'm presuming the transistors and fuses are still good.

Hey Jim, here's a new test print labeled per your guidance. Please let me know if you can glean anything from this. And yes, transistors and fuses all appear to be working properly.
 

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My assessment is a dead print head. The K/C head has been driven by both the K/C signals and the M/Y signal and shows good. The displacement in position is due to the firing timing. This confirms you are getting all the signals from the head board. The fact that the M/Y head doesn't fire at all, regardless of the signals supplied to it confirms it appears to be dead. Sorry for bad news...
 

Nate.H

New Member
My assessment is a dead print head. The K/C head has been driven by both the K/C signals and the M/Y signal and shows good. The displacement in position is due to the firing timing. This confirms you are getting all the signals from the head board. The fact that the M/Y head doesn't fire at all, regardless of the signals supplied to it confirms it appears to be dead. Sorry for bad news...

That's okay, at least now I know it's worth the investment in a new printhead. Thanks so much for your help!
 

Nate.H

New Member
Installing the new printhead was a success! The black is still fuzzy, but it's been like that for a while and we're used to it so I'm not too concerned about that. Thank you all for your help with this!
 

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Ultraman

Ultraman
Installing the new printhead was a success! The black is still fuzzy, but it's been like that for a while and we're used to it so I'm not too concerned about that. Thank you all for your help with this!

Hi! Nate,
If I were you, I would swap your new print head to black and black print head to yellow print head because black has the heaviest pigment and usually the most used and first to go. Currently your black deflection pretty bad and your black prints will suffer. Beware you would need to do head adjust and alignment again
 
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