Woo woo, I'm now 6 for 6 on repairing the "broken" Cricuts I got off eBay. (ok, Danny M. gets 95% of the credit for the one with the busted middle-layer board traces)
The last holdout was a Personal model, which would beep three times when powered up. Nothing from the LCD, all the keyboard lights would come on.
I started by plugging a known-good power supply into it, just in case, but it didn't make any difference.
Next, I removed the bottom cover where the motherboard lives, and immediately spotted the culprit. The LCD header was unplugged.
After plugging it back in and powering it back up, angels sang, it started right up and gave me the "Cricut 1.0 OK"!
Incidentally, I had been wondering if the earliest firmware versions had perhaps not been read-only, so I plugged in my handy programmer card and attempted to download the firmware.
At first I thought I had hit paydirt, the file was NOT all 0s like the others, but alas, I realized the bytes were all sequential numbers in an interesting pattern (high-byte increasing across, low byte increasing downwards).
This machine looks pretty much unused and gleaming. I wonder if it was bad right from the factory? How else could a header just come unplugged like that?
One thing that always bugged me about using pens in my Expression is the super short limit on pen length. I love the Staples mini gel pens, and I've gotten pretty good at shortening others, but some (like Sharpie paint pens) just not feasible to do this with.
One video on YouTube shows someone with a Personal model who removed the keyboard which allows a full length pen to be used. Unfortunately, this requires removing the end caps which is kind of a hassle. The Create is even worse, the body of the case extends underneath the keyboard and completely eliminates the option altogether.
Anyhow, with the help of a friend at the hackerspace the other night, I finally figured out how to do this EASILY on the Expression.
Here's photos showing how:
Using the head of the special tool, slide the latch towards the rear of the machine. It's pretty stiff, but don't worry about breaking anything. You could also use a flathead screwdriver for more leverage.
Once the latch clicks, lift up on the left side of the keyboard. The right side is just held down by some plastic fingers in holes in the case and will release when you move the keyboard a little to the left.
Taking care not to tug too hard on the wires, you can now lift the keyboard up and out of the way, eliminating any length limit on pens. On mine, the power wires on the right side were especially short. Taking the right side endcap off allowed me to release a bit more wire, but it doesn't really take much.
Reversing the process is pretty easy, just tuck the right side back in the holes, press the left side down flush, and use your special tool in reverse, this time to pull the latch back towards the front of the machine until it clicks.
I've been looking into and learning some secrets of the Cricut's cutting carriage.
First off, it appears to be a custom version of the US Cutter "Refine EcoCut" carriage. See for yourself: http://www.uscutter.com/Refine-EcoCut-Carriage_p_1669.html - the only difference I can see from the photo is there are TWO positions in the tool holder. The manual says the front hole is for the pen attachment, and the rear hole is for the blade attachment.
Regarding cutting pressure, both the Refine manual and in other places, the maximum pressure is claimed to be 400g (or 0.88 lbs). However, a colleague of mine actually tested it and got an indicated 0.4 lbs at +4 vdc. I'm planning to retest this on a running machine (after disconnecting the stepper motors!).
Finally, I originally believed this to be a solenoid, but after taking the carriage apart and checking voltage readings, it was discovered that it's actually a voice coil! Basically just like a speaker without a diaphragm. Normally, a -2vdc current biases the blade upwards, and switches to +4vdc (at maximum pressure) to press the blade downwards.