canon ipf 750 need advice in diagnosing problem

[tmw]

I've been occasionally sent to look at ipfs, although they are not normally what I work on. I have a manual, but it only takes me so far.
The original problem was 03130031-2f2a, feed roller detection error. The roller was turning at startup,then went into code. I first started with replacing the feed roll sensors and encoder wheel. The code reoccured just the same. I tried seeing what would happen in service mode, and it got a 03130031-2f14 error when I tried loading paper. Both codes left me the option of replacing the main board.
I was going through the posts and they mention various things, such as printhead, purge unit or firmware. The customer said canon told them to try a new printhead, supposedly that should rule it out. I noticed that the ink tubes were all empty. The other techs were complaining that the manual was vague, and the support line techs sounded like they were guessing at things.
Since this might be a guessing game, I wonder from the people who know better then I do. What would be a reasonably educated guess as to what the next step I should take? Thank you, I appreciate the knowledge that's out there.

[guitar9199]

If your ink tubes are empty, that would lead me to think the Purge Unit might be bad. QM3-5988-010

2F14 if powering up in user mode, try booting into Service Mode and clear the error and powercycle. If the error returns, Main Controller PCB shot. QM3-5820-010

The 2F2A error on a feed usually points to a bad feed sensor... Part # WG8-5849-000

Good luck.

[MunsterTech]

hardware error 03130031-2F14
turn off printer, wait, turn on again

Power on again, hardware error 2,

ASIC Register not writeable (hardware err2)
could not write to the ASIC register on the main pcb

replace the main PCB

havent worked on these for a good while, but thats on the trouble shooting guide, couldnt find your first error on there. hope it helps
A