The one with the evil MFT.

What do you do when the service manual fails to support you? You take off the kid gloves and kick some ass, that’s what you do!

I’ve been trying to resolve this issue with a non-working manual feed tray on an HP Color Laserjet 4700DN (Q7493A). If you clicked on the link, you’ll notice that it’s big, but not as massive as the psycho-heavy HP Laserjet 4345mfp (which I have installed, but have yet to service). Anyway, the unit I’m referring to is just the base unit and extra 500-sheet feeder with no other add-ons.

Anyway, it’s a GOM (Government of Manitoba) asset, for those of you who are curious as to who in their right mind would purchase such a paper weight of a printer. As it turns out, the printer as a whole works fine, except for the MFT. If a user tried to print to the MFT, nothing would happen, it wouldn’t feed, and the printer would automatically attempt to clear the paper path and error out with a non-existent 13.XX paper jam. I did a simple thing first – checked for any jammed paper. Nothing. Then, I ordered a new paper tray. The problem persisted. So, I consulted the service manual, which listed a bunch of steps to take. I decided to skip the whole diagnosis and I ordered both of the suggested parts to replace, so that I could troubleshoot all the steps at once. Since the printer was working for the user, just without that insipid feature, I did my best to delay fixing it. Damn rights, it’s quite an intimidating piece of machinery. Also, I had an excuse – the parts were on backorder (actually, just one of them was – I had already received the other one).

So, anyway, last week, I got the last part in and thought to myself, ‘Okay, new piece of hardware, so that means a learning curve will be required, along with some fumbling in the service manual – I’ll need about two to three hours, tops. Better do this frakker after hours.’ I didn’t listen to myself and went onsite with some key printouts of the manual, as well as the PDF of the whole manual on a USB key, along with the two parts I ordered – the paper pickup motor assembly and the DC controller PCB. I swapped in the paper pickup motor assembly first – it required taking apart a good deal of the printer – the main motor assembly, the delivery motor assembly, and even the cartridges (well, there were more parts than that, but they are too numerous to list (also, I forgot what they were called)). Too bad I did all that work for nothing, because the frakker still wasn’t feeding from the MFT.

I took my advice the second time, since the first attempt made me look like a fool in front of an entire department of government employees. I went back onsite on Saturday and took the whole thing apart again. This time, I replaced the DC controller assembly. Luckily, there wasn’t that much to take apart this time around, but the board had tons of connections. Seriously, if you ever saw the diagram for solenoid connectors, you’d shrink back in cowardice. At the same time, I was thinking, ‘What the hell does replacing the DC controller board have to do with the MFT not feeding?’ Apparently, the service manual never needs to explain itself, as it is not human and has no feelings or tact. If it had an ass, I’d kick it. Anyway, a test print yielded the same results – a FUBAR MFT. I decided to throw the service manual away and do things my way. This is where the kid gloves came off and I got serious, son! I kept the right side of the printer open so I could see for myself what was going on. I powered on the printer and watched each and every gear go through its calibration, leaving nothing to scrutinization. When I did a test print from the MFT, I saw all the gears spinning, despite its failure, so it was obviously something inside. I pulled open the tray and referred to the parts diagrams in the manual – the only part inside the sheet feeder unit that was available to order was the paper pickup gear assembly. So, I ordered it. I got it in today, and decided to get it replaced after hours today. By that time, it was lunch, and I had no vehicle to go anywhere, so Mom picked me up, I ate lunch at the restaurant, and I went home, relaxing for the afternoon.

Relaxing actually means reading an e-mail from a female colleague that invited you to Flixster, joining Flixster, and rating over 50 movies for the hell of it. Hahaha. I actually ordered Karyn Bosnak’s first novel, 20 Times A Lady, from Amazon two days ago. I got it in today at lunch, so I started reading it afterwards. Funny stuff, as expected of Karyn.

After that, I got dropped off at work, and I began my foray into battle with the 4700. When I referred to the manual on how to replace the part, I was shocked to find that there were no instructions.

「ありえないよーーーーー！」 I exclaimed as I spiraled naked into a black hole.

Anyway, I had to wing it somehow, so I tried to figure out how to remove the blasted thing. Unfortunately, I saw no easy way, as the whole thing was wrapped in plastic that didn’t seem to have any sections to remove. I had a gut feeling that I’d have to disassemble the entire top half just to get to the bottom. That, and the whole unit was just a tad bit heavy to lift and maneuver upside down on my own. So, I physically attempted to pull the thing out from inside. Removing the screws was difficult enough, since I didn’t have the same amount of leverage to do so. However, it was all for naught, as the assembly would not be removed. I was running out of ideas. I was also getting hungry.

Then, it hit me. Ouch.

After recovering from getting hit, I got an idea. I inspected the assembly I ordered to discover any clues on how to replace it. I scoured the part carefully, and realized that there was really nothing in it that would need replacing unless some of the gears were broken. However, if that were the case, I would have heard something by now after all the test prints. So, the only things that could be replaced were the two solenoids in the assembly. So, I experimented and took the assembly apart. Using that brief experience, I duplicated it on the assembly in the printer, and with a bit of difficulty due to the tight space, I was able to remove the exposed cover of the assembly. I was very impatient by that time, and picked the easiest solenoid to replace – the one that was mounted on the cover. I swapped the solenoids, re-attached the assembly cover, and tested printing again – success! I beat the frakking bastard!

So, the moral of the story? Never work on hardware this big. Oh, and if you ever find yourself in charge of writing service manuals, make sure you write removal/replacement instructions for every little thing, even a little plastic tab that comes off with one screw. I would almost hate HP, but Dell is much worse. You can’t even get a hold of their service manuals, unless you call them directly. What’s THAT about?

以上。。。であります。