Mutoh RJ900 not printing some channels help

[conan981]

Hi to all. I have a mutoh rj900 that does print good BLACK channels, but only one channel for the others..


It is a board problem, since i replaced main board with a working one i use for tests and all is printing ok.
Now.. someone can help me with a service manual and/or suggestions what component/s should be replaced
to repair this weird error?
thanks in advance for any hint

 

[RG]

Wow! That is an unusual problem. I have a 1204 which is about the same as a rj900. Check your maintenance station and make sure it is in good working order. Is there air in the lines of the channels that are not printing? Could be a problem where the individual ink lines each split into 2 lines, just before then go into the dampers. Have you checked the dampers? Have the dampers been replaced recently? Send me your e-mail address and I can send you the rj900 service manual.

 

[Solventinkjet]

If another board prints fine then it has to be the board,. My first thought would be bad transistors. The transistors amplify the signal that goes to the heads and if a transistor fails it can affect single channels like yours are. Especially on older machines.

 

[conan981]

thanks for hint.. that has been my first suspicion, when i checked the board the first time, it had indeed an A1746 and C4131 not working and transistors WM and WL too.. but now all the power transistor seems to be good. this is the reason i would check with a service manual if i could find it

 

[Solventinkjet]

thanks for hint.. that has been my first suspicion, when i checked the board the first time, it had indeed an A1746 and C4131 not working and transistors WM and WL too.. but now all the power transistor seems to be good. this is the reason i would check with a service manual if i could find it

The service manual does not have any info on repairing or even diagnosing boards unfortunately. It will basically say to replace the board and be done with it.

 

[unmateria]

Check the 2 head cables before changing the transistors and fuses (check all fuses, specially F2). I fried one 220 resistor too near those transistors you said.

Enviado desde mi Nexus 6 mediante Tapatalk

 

[unmateria]

Check the 2 head cables before changing the transistors and fuses (check all fuses, specially F2). I fried one 220 resistor too near those transistors you said.

Enviado desde mi Nexus 6 mediante Tapatalk

I reply myself LOL... I fried one 220R on each transistor. I suppose you have checked them if you checked the transistors but just my 2 cents

Enviado desde mi Nexus 6 mediante Tapatalk

 

[Allexander]

Hello all.anyone has a printhead for this printer?
i think mine is dead.i have magenta ink going in yellow tube, and black tube.and it seems to pe losing ink to the sides of the printhead, not on the nozzles.
DX5 printhead, for sublimation.

 

[SYYED SHAKEER]

Hello all.anyone has a printhead for this printer?
i think mine is dead.i have magenta ink going in yellow tube, and black tube.and it seems to pe losing ink to the sides of the printhead, not on the nozzles.
DX5 printhead, for sublimation.

Solventinkjet on this site/forum/post/ thread can definitly assist you.

 

[wedgeman]

Did anyone ever find a service manual?
I recently found one, but the wiring diagram page is a copy of a copy of a copy, and is illegible.

 

[unmateria]

For manual you can use the one forma valuejet 1204. Is pretty much the same. For printhead wiring, the 2 ribbon cables. Just disconnect from the old one and connect to the new one one at a time or mark the cables. Take a photo of the rank in the sticker first. You will need it for setup the rank (the voltage values for that printhead)