9810 question and offer

[Tony Duell]

(02-15-2014 04:49 PM)dramsey Wrote:  Another question: As you can see, there are several printhead elements that fire all the time, leading to vertical lines in the output. I'm assuming this is an electronics issue rather than a physical printhead issue.

I have another 9810 I can use for board swaps. So: any hints on which boards I should swap?

Firstly, I am not going to help you to swap boards. I will help you to find the fault.

The printhead is 80 elements. Electrically they are wired as a 20*4 matrix with the diodes on the PCB on the bottom of the printer. The 4 power transistors on this board select one of the sets of 20 elements, each element in the set is then controlled by a transistor on the printer interface board on the side of the printer. In turn these transistors are controlled by a long shift register, in part it's the normal processor I/O register, the rest is on the printer PCB.

My guess is a failed transistor on the printer interface PCB. Take the printer out, take out the 3 screws on this PCB and ease it off the edge connector. Then you can check for shorted transistors there.