reprap

Results of today's printer work

A very confused evening with a good outcome.
I decided to poke around a bit, and fired up the machine. I immediately hit problems because I could not get sensible readings from the thermistors, both the hotend and the print bed read all over the board, from 0 to 38 degrees (actual room temp is about 22). I spent a full 2 hours on this, eventually completely disconnecting everything from the RAMPS board, removing it from the CPU board, wiring a pot to the thermistor input, doing a careful inspection of the board, etc. The thermistor is as simple as circuits get, a 2-resistor voltage divider with a 10uF filter cap going into an A/D channel on the Arduino. Everything was fine yet there was some source of noise in the system.

Long story short, after 2 hours of dinking around and chatting with one of the designers of the board on the IRC channel, I suddenly realized that I'd moved the board to the USB hub instead of the PC, and that hub is a hunk of junk. The board runs from USB power. I moved it to the PC and the problem went away.

feh.

Anyway, in the mean time I also hooked up my new power supplies though they are not yet in an enclosure. They work fantastically. I'm going to build a box for them later, and I think I will be printing an enclosure for the electronics after my new heat sinks arrive, then I'll have to do some rewiring because I made some of the wires way too short.

I was thinking I'd try to print something on the broken glass, it's held together by tape on top, but it's bent in the middle by about 0.75mm and that's too much for a good print.
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