HP M601 blank screen/cold reset procedure

[Tom]

Ok, here's what happened. I ordered one of these printers that I love cause I don't care much for the current models, it had a low meter of 14k. Arrived in great condition, well packed. I fired it up, printed out confirmation and usage pages to verify, ran a few tests to check for jamming or anything, it looked great. Except, it had older firmware. No problem, they always do, so I popped out my handy dandy thumb drive to upgrade. I went to look for the upgrade under device maintenance where it usually is and nothing was there. I looked everywhere, couldn't find it. A quick google search showed me another way of turning on while pressing the X button repeatedly and a different method came up. I followed the instructions and it seemed to copy the files just fine, then it turned off as if rebooting but never came back on. I turned on manually and now I have a blank, dark screen. I guess I've been lucky in the past that all the printers of this series I've ordered were 2014 or newer and had 2014 firmware. This one had 2012 firmware which I'm guessing is why I had to do a peculiar method of updating. I thought I knew these machines well, but never had one from before 2014, it must be one of the first year machines but it's immaculate so I want to save it. I don't see any way of doing a cold reset without having the screen though. I turned the lights off in my shop and I can see a dim backlight on the screen, so I know it has power, but it never brightens up and says anything. Obviously the update screwed it up, but I have no idea how to fix this with no screen to go by. Any ideas? It's too cherry to relegate to the parts machine pile.

[Tom]

Fixed it, I had a spare parts machine and a few minutes before thanksgiving this morning to play with it. Since I was almost certain it happened due to firmware update, I bypassed swapping out the display and went straight to the formatter assy. Tried the HDD first just to see, but nope it was the formatter board locked up. Put another one in it and it fired up. Had to let it do the used board reset, but it took just fine. It had older firmware also, but it was from 2013 not 2012, and it allowed me to update the normal way by scrolling to it. I guess that first year was the issue, and it didn't like updating to 2022. It did change the IP address, but kept the usage count. I don't know where that info is stored, I always figured it was on the formatter or HDD, but I guess not.