• I want to thank all the members that have upgraded your accounts. I truly appreciate your support of the site monetarily. Supporting the site keeps this site up and running as a lot of work daily goes on behind the scenes. Click to Support Signs101 ...

LEJ-640FT Fuse - Troubleshooting

sajego

sajego

Since 2010
A few weeks ago my magenta stopped printing in the middle of a large job that really needed magenta. I troubleshooted the ink system parts and got it partly working again, and then it was gone completely along with the Cyan. Turns out the F1 fuse was blown. My tech (unofficially) said try unplugging the ribbon cables between the print head and carriage board to see which print head was the problem. Either both are or neither are, the fuse blows any time I turn the printer's subpower on.

To me, this doesn't sound like something that can be solved by replacing print heads, and I'm worried the new print heads will be damaged.

What's the next step? I'm happy to have a tech look at it but I don't have a local tech since I moved to the Reno area from Virginia and the local salespeople don't want to support my machines since they didn't sell them to me.
 
Solventinkjet

Solventinkjet

DIY Printer Fixing Guide
I had a similar issue with an XC-540 printer recently which uses a similar head board. It ended up being a bad head board. If it blows no matter which head is plugged in, it could be a bad trailing cable or even a damaged/dirty slider board but my bet would be on the head board. I'm not a Roland expert though. Maybe Jim Hancock has another idea.
 
sajego

sajego

Since 2010
It blows with whichever head is plugged in or with no heads plugged in which isn't normal behavior (I checked using a different fuse group).

((I'm struggling to keep the boards straight, the head board you mention is attached to the print head and there's one for each print head? Or is it the board I'm thinking of as carriage board where the ribbons go from each head? Or is it the board where the fuses themselves are?))
Answering my own question: the one where the fuses are.

Thanks for the reply. Sometimes I wish I wasn't an engineer so I could just pay someone to do all this without feeling like I should be able to do it myself. :)

Sara
 
Last edited:
Solventinkjet

Solventinkjet

DIY Printer Fixing Guide
sajego said:
It blows with whichever head is plugged in or with no heads plugged in which isn't normal behavior (I checked using a different fuse group).

I'm struggling to keep the boards straight, the head board you mention is attached to the print head and there's one for each print head? Or is it the board I'm thinking of as carriage board where the ribbons go from each head? Or is it the board where the fuses themselves are?

Thanks for the reply. Sometimes I wish I wasn't an engineer so I could just pay someone to do all this without feeling like I should be able to do it myself. :)

Sara
Click to expand...

It's the board with the fuses on it. That's where the signal gets amplified and my theory is that one of the transistors goes bad and pops the fuse. If you know how to test transistors, you might be able to fix the board rather than replacing it. Unfortunately my electronic skills end at testing fuses!
 
sajego

sajego

Since 2010
Solventinkjet said:
Unfortunately my electronic skills end at testing fuses!
Click to expand...

Same. Mechanical engineer, not EE. I also read in another thread that the transistors are paired and replacing just one can cause issues too. So where's the best, fastest place to get a head board from?
 
Solventinkjet

Solventinkjet

DIY Printer Fixing Guide
sajego said:
Same. Mechanical engineer, not EE. I also read in another thread that the transistors are paired and replacing just one can cause issues too. So where's the best, fastest place to get a head board from?
Click to expand...

Try Ordway Sign Supplies in Van Nuys, CA. They should be able to help.
 
J

Jim Hancock

Old School Technician
You should check the output transistors on the headboard. They are the transistors mounted to the big heatsinks. Read the outer 2 legs of each transistor, they should read around 42 ohms. They are marked as C4131 & A1746. Most likely you are going to find one or more are shorted and this will continue to blow fuses until they are replaced. If you do not have anyone to do this, I offer it as a service.
 
N

netsol

Active Member
am pretty sure that NTE, TCG &ECG (if they still exist) make replacements

original or aftermarket, always change in a pair

use heat sink compound (the goo behind the heatsink the transistor screws to)
 
You must log in or register to reply here.
Top