I'm working with Shopbot on this but we still don't have a resolution. Perhaps people on the board can offer suggestions.
Background:
- Shopbot PRT Alpha 48 & indexer mfg. in July, 2005
- Windows ME on a 1.7Ghz processor with 256MB running latest Shopbot software. No network connection. I do not have easy access to another computer to try a replacement.
- Porter Cable router
- Shop is metal clad wooden building in a rural area and NOT near high voltage power lines or RF transmitters
- Cables are run neatly: not coiled and are well seperated.
Symptoms:
We've had occasional communication loss issues since the beginning. Switched to the Quatech USB/serial interface. Still had occasional communication losses.
Beginning 1/10 motors began randomly making a grinding noise and the machine would either lose position (gantry traveled farther than shown on the screen) or would do random reversals in Y and/or Y. This occurred while surfacing the sacrifice board with practically no load on the router bit.
Problem also occurred during air cutting with the router not powered on.
Replaced the control board with one sent out by Shopbot. Have not had the random reversals but still will randomly make the grinding noise and lose position. The limit switches do not stop the machine when it is making the grinding noise but they do work otherwise. I can still use them to XY home the Shopbot.
We have tried running without the limit switches, Z-zero plate or indexer motor hooked up. Still malfunctioned.
One of the relays is very slow to close after hitting reset. Shopbot is sending a replacement but they didn't believe a defective relay would manifest this behavior.
There is another Shopbot PRT in our town that the owner may allow me to use in his off hours so at least I can finish a critical job -- but I'd rather use my on system.