LEJ 640 blowing fuse1

[Rusty B]

I recently purchased a used Roland lej640 hybrid. It keeps blowing the f1 fuse on the head board. I installed all new printheads new head cables dampers and cap tops. The magenta and cyan don’t print anything on a test print. The yellow and black are perfect. So far I swapped the cables from the black and yellow heads to the cyan magenta and they will print on a test print so heads are good. I used a meter to monitor the fuse and it blows immediately after powering up. Maybe 8-10 seconds after I power it on. I then removed the head board and the first and 2nd transistor read .000 and each leg has continuity with every other leg on that transistor. Is that the issue and what could be blowing the fuse? I have checked the ends of all cables from the heads to carriage board then on to the head board.

 

[cornholio]

Shorted transistors will certainly blow the fuse.

 

[Rusty B]

Shorted transistors will certainly blow the fuse.

Thanks! I will get a new head board. I was thinking about trying to remove the transistors that are bad which seem to be the 1st 2 on that channel but they don’t look easy to remove with the small soldering iron I have.

 

[damonCA21]

hi Rusty, I do board repairs for all Roland printers and can diagnose the board and replace any faulty components. It could be bad transistors but there are also other reasons the fuse can be blowing

 

[damonCA21]

No need to replace the head board though, repairing it is more cost effective you are right with the soldering though! it is very easy to damage pads and traces if you aren't used to doing it