Bridgeport Series "I" will not home, please help technical school in need!!

[phantomcow2]

I am representing a technical school here, this is not my machine.
X y and Z will move, but will not home.
If i tell the machine to home it will not home however it moves right ot limit swithces, and shut off.
Commands that show up:
Zap does show up.

We have a series I bridgeport, 1983. All electronics are onboard here, everything is physical. In order to complete any operation, all axes must be homed. However we are having difficulty because the axes will not home! We try to home, all axes move to limit switch, then normal limit error occurs. Not picking up homing sequence.
The following error notices occur:
ADE
ADE transfer to homing due to Zap


THis is most certainly a problem with circuitry.

Thankyou for any helpful replies, if you have any questions or in any way can help but need more information, please post a reply. Thankyou

[machintek]

ADE = Axis Drive Enable
ZAP is a emergency stop condition generated by the FMDC because it saw a problem. The only way to see what caused it is to use the FIST event monitor. This is a diagnostic tool built into the FMDC board using a PC using RS232 communicating with K3 on the FMDC board. It is the maintenance manual.
With a high degree of certainty you have a BOSS 8 which has a two line LCD display.

What you do not say is does the Z move down and back up, is it followed by the y moving away from column and then back to column, and then does the X try and home and is it then that it goes to ZAP.
Lets say it is the X. Does it move off the home switch and back on? If it does not move off the home switch by itself (if it is on the switch) then it does not see the switch. Might be a bad switch or broken wire. Maybe the switch is full of coolant.
If it moves off by itself and back onto the switch but goes to limits, it may not be adjusted correctly or the marker pulse may be missing from the encoder (bad encoder, bad cable, or bad board).

George

[machintek]

After rereading your post, I am wondering if all three axis are moving at the same time to try and home. Never seen this happen. This would be a control issue. The BOSS software is burned onto PROMS.

George

[phantomcow2]

I will ask the instructor for the class tommorow. I am going to see if the school can take some pictures tommorow.
i will pass all of that on though, thanks for a reply!

[phantomcow2]

When you say control issue, do you refer to the main circuitry? Last time we had to have a guy come replace the CRT it cost 400 dollars. To repair (or replace circuitry) will most definitely cost more than that. I've seen some hobbyist who take the Series I, rip out the electric guts, and replace them with modern servo drives. Wondering if that would not be the best route for us.

[phantomcow2]

What a shock this was! We moved the Z down, not even .200", it initiated home. All is working.
Awkard, we have moved the Z up and down many times without luck...

[machintek]

Someone sprinkled pixie dust on the machine?
Do not argue with success.
Yes, repairs can be very expensive. And your thinking is very sound.

George