Emco Compact 5 interface with linuxcnc -- random/intermittent estop toggling.

This relates to an interface issue that cropped up with an EC5 PC running on LinuxCNC using Sam's config, so it seems like this most be the best place to post. If not, I'll happily move it.

I've been running a EC5 PC on LinuxCNC with no problem until it recently began to toggle the EStop by itself. It was very random and fairly rare at first, but got progressively worse. The bridge rectifier was recently replaced and should be good. All fuses appear to be good. I've checked connections and don't find any that are loose.

What usually happens is that when I open LinuxCNC, all looks good until I power on the machine with the key switch, then the EStop button in LinuxCNC turns pale.

I removed the chip-guard cover when I first got this machine, so that switch is in a position where it should always see the lid as closed. While fiddling around I discovered that most of the time, but not always, I can get the EStop button in LinuxCNC to toggle off (machine power on) by pushing up on the lid switch a little. Sometimes that is effective for a quite a while, other times the switch either dims out again and stays dim or toggles itself on an off randomly. None of this causes any power loss (either main or spindle motor). I'm just not able to control the machine with LinuxCNC.

I tried inserting a dummy plug to permanently disable the lid switch, but all that did was deprive me of the ability to get the EStop button to un-dim.

Any thoughts about what the underlying problem is?

Thanks for the reply, but I don't think it's the switch, even though manipulating it could at least temporarily seem to resolve the problem. But when I simply short the two circuits and by-pass the switch, I still have the issue. And it continues to be somewhat intermittent. I just lose my ability to tamper with it.

It's clearly a machine-side issue, though.

Thanks. I have a DVM. Just very challenged in using it. I'll figure out how to do that, though.

Should the rectifier be getting very hot? It is, which I haven't noticed before, although I don't know that I would have.

I have several of these machines and and a couple have begun to develop control-side idiosyncrasies that I assume are related to age. I need to develop a plan to update/upgrade them. If anyone knows anyone to recommend who might be able to help with a reasonable distance from Kansas City (which would include St. Louis), I'd welcome recommendations. I'm not looking for charity. I really want to stick with LinuxCNC.