Agree but I think you meant to say Y/M.Is the C/M head firing? If so swap the cable from that head to the C/K head.
DOH! No excuses for that I've had plenty of coffee.Agree but I think you meant to say Y/M.
Fuses are soldered on the SP300 and 540's. They are testable inplaceHave you flushed the pump tubes? They might be clogged which wouldn't allow ink to flow into the head after install. Also, double check the fuse outside of the machine. Sometimes they can give false positives when still installed in a machine. If the fuse and transistors are good, you can confirm ink is flowing through the head, and it still doesn't fire, the head could be fried and/or there is some other mysterious electrical issue happening.
Fuses are soldered on the SP300 and 540's. They are testable inplace
This turned out to be the case. Checked the fuse again and everything works! Prints like a new machine! The fuse can check good and not be soldered to the board properly. Thank you for all the advise!It depends on the exact model. Later versions had replaceable fuses. I also agree they are testable in place but I have had many customer say a fuse was good when in reality it wasn't.