Another Printer Partout

Welcome to another edition of "Taking Apart Printers!" Today, we're taking apart a HP Photosmart C4680. I'm kinda excited about this one because it has a scanner and a tiny LCD screen, so that's pretty exciting. This was my printer, so I'm glad I'm recycling it. It's nice to at least try in full faith to reuse some parts to make something else, even though I'm only learning how. It beats the hell out of buying parts, right? Also, taking things apart is fun.

Here is the victim:

The first apparent problem was that there were no visible screws. None. Whatsoever. That is until I observed closely. There were three screws holding the top scanner assembly onto the bottom printer assembly. There was a fourth one but I couldn't find it so I basically broke the plastic around it to get the top part off. We'll work on the top part later.

The first thing to come out was the logic board. The fact that all of the screws so far were T10s made me happy because I didn't have to change the bit of the drill. We'll get back to the board in a while.

At this point it was just a matter of attacking this thing with a screwdriver. There were only T10 and T9 screws which made it super easy. There were also some annoying plastic clips that had to be disengaged/broken to get parts apart. I didn't spend too much time tearing apart the print roller or the carriage assembly because based on past experience there isn't much there to be had. This is the printer with the bottom taken apart.

Then I moved on to the top. After fussing with clips, I was able to separate the top part further into three interesting sections.

After that is was just more prying and crying. The screen was actually fairly hard to pull out, but once I got it out it was nice. Now that we have separated the interesting bits from the plastic, let's get rid of the stuff we don't need.

We're going to look at five parts. The main board, the screen, the reader, the scanner bit, and the tiny PCB that has a button and a light.

The main board is an enigma. The markings on the chips yield no results on Google. I'm pretty sure that all of the chips on this board are made on contract so their datasheets will not be available. However, I could deduce which chip was the main processor (the big one) and the memory (the one next to it.) I also think it has a 64kb Serial EEPROM chip, but this is only vaguely the number on this small chip.

Next we move onto the screen. On the screen board we have a PIC16F727 Microcontroller. That whole assembly seems to be pretty rock solid, so I think I'm not going to disassemble it. It seems to me to be so well assembled. I might be able to make it work. I like to make false promises.

The SD card reader is another story. The chip on it implies that the wires coming off of it are USB2. But the connector has more than four pins on it. That'll probably be the easiest thing to reverse. But for now, I'm putting it in the pile for later.

Next we have the scanner bit. At the very least this would make a good light once I figured out the pinout of the ribbon. It also has a motor on it. I'm very doubtful of getting image data off of the sensor strip, but it's worth a shot.

Finally, there's this little PCB.

Why did I include this? Well, I'm going to reuse the whole thing in the next part of the Hard Drive turn table, so I thought I'd discuss it here. This board has four pins. I'm not sure of the pin out just yet, but it has a tactile button, an LED, and a SMD Transistor. Just some simple controls for the board.

Anyway, this printer has spawned some additional project ideas for me. I just need to finish up some of the ones I'm currently working on so I'm not drowning in parallel projects. The turn table is close. I just need to get the time to make it look good and maybe make the platter spin by itself. I think that'll require more amperage than I have from USB 2.0, though. But I digress. I'll get though as many as I can in the time I have.