Disaster!

[zorlack]

Last Friday I finally had a little bit of time set aside to make the proximity sensors on my bot work. Or so I thought.

While I'm looking over the bot I notice that one of the wires on one of the X axis motors has come loose. So now I have to figure out how to get that wire back into the motor connector also.

While in the process of debugging this I unplugged one of the motors with the power supply switched on.

I was then treated to a little fireworks display courtesy of the SB control board. You know that sinking feeling you get when you've totally screwed up badly?


8341
This is where the smoke came out


So it's 4:30pm on a Friday. And I'm staring at the smoldering remains of my control board. Ugh.

Monday morning I had SB overnight me a rebuilt 3.x board. But now I have to install it and I'm a little bit worried about burning up a second board. The reason I'm concerned is that prior to burning out the first board, I realized that the motor with the bad connection wasn't providing any driving power.

When I unplugged the other X axis motor and tried to drive it using one motor, the motor with the loose connection just made noise. And moved a tiny bit. I'm still assuming that I have to work on that connection a bit.

Anyone have any thoughts or advice how to proceed with the new main board?

-Dave

[waynelocke]

I would consider returning the rebuilt board to Shopbot and replacing it with the newer 4g board. The board is more expensive but far superior and allows much faster speeds. It also is less prone to blowing drivers if you forget to turn it off before unplugging something.

I think that there is something in the documentation for the machine showing the wiring of the connectors. If you didn't get the documentation I am pretty sure that it is online.

Talk to Shopbot!

[zorlack]

Well I installed the rebuilt board on Friday. I decided that I wouldn't reap most of the benefits of the 4G board since I use a router and generally don't have to worry about extremely narrow tolerances.

The board went in with no problems whatsoever, and it gave me the opportunity to rewire everything. The previous wiring job had just about fallen apart. I even got the proximity sensors working!

My next project is to add a z-zero plate at the surface of the table. That way I can automate the Zeroing on all three axis.

I want to do something similar to Ed Lang's Z-Zero Rod (http://www.shopbottools.com/getting_started.htm#Zero). I'm not entirely sure where to source the Aluminum from...

Suggestions anyone?

[myxpykalix]

try a local welding shop? They should have a piece of scrap.

[jamesgilliam]

Dave, Most hardware stores carry some aluminun stock, in various forms, flat, angle.... it should be in with the rest of the metal they carry.

[knight_toolworks]

I just used an aluminum plate cut some slots in it and screwed it to the table. I don't mill it flush with the table .I zero the bit on the table and use that to set the plate accurately. I bought it on ebay dirt cheap.

[ed_lang]

Mine was a scrap. All above suggestions as to where to source the material are good ones.

[bcammack]

I used contact cement to bond a small square of blank, copper-clad printed circuit board to the table top. Soldered a length of wire to one corner and ran it straight down through the top to the control box. A randomizer routine in the Z-Zero code picks a random point within the boundaries of the plate to reduce wear.

[zorlack]

Is the reason for using aluminum that it's softer on the bit?