Missing one channel of Yellow - Mutoh Valuejet 1204

[Motostars]

Hello all, any help greatly appreciated.

I've got one channel not firing, (yellow) on my VJ1204. All other blocks of nozzles firing fine, one yellow block completely missing. No obvious signs of ink starvation, air locks etc. Was working fine before. Not had it apart or anything. I did have an issue just before where the head started dumping ink across the whole print on large sections. When stopped and restarted it was ok again. That problem seems to have gone, but now I've lost a block of yellow. Is this bad head cables?

Cheers.

 

[chrisphilipps]

You had a short in the print head circuit that has probably blown the driver chip for that yellow channel on the main board. This short is what caused the ink to be laid down across the width of the printer. This short normally is in the CR cables, head cables or sometimes the head itself. You are definitely going to need to have the printer looked at.

 

[Motostars]

Absolutely marvellous. I sense a wallet emptying session coming on.

Thanks for your help.

 

[Motostars]

Can you identify which chip it is on the mainboard that controls this? Does anyone do mainboard repairs?

 

[chrisphilipps]

If you look at the mother board you will see a large heat sink in the top right hand corner. Mounted to this heat sink is the 8 head driver chips. One of them has failed. I don't know which one is for which channel. If you know how to use a multimeter you can check all 8 chips to find the one that is different.