xXxOlivierxXx
Plastic
- Joined
- May 28, 2019
Hello everyone
I have a friend who is an machinist and owns an old Bridgeport mill with an even older Servo Type 100 power feed.
He never installed a limit switch on his power feed and then one day, he turned on the power feed to maximum speed by accident and the mill hit the end, apparently killing the servo because it released some magic smoke.
Since Type 100 circuit boards are pretty much impossible to find nowadays and the type 150 boards are over $100 plus tax and shipping (like this one or this one), I wanted to attempt to repair the damaged board myself.
I'm not an electronics expert but I do have a lot of experience. This is what I have found so far:
When I plugged in the 110v cable of the power feed, the breaker would trip instantly. I opened the Servo unit, I noticed that the circuit board had short-circuited traces right where the 110v lines come in. I repaired the damaged traces and then started diagnosing components. All Varistors are fine (open, not shorted) and I found that the Bridge Rectifier diodes were dead, they had continuity on both directions. I replaced all 5 Diodes (400v 6A) found in the Bridge Rectifier area, replaced a blown 16v capacitor, tested all resistors and all of them appear to be fine.
Now, when I plug the 110v cable the breaker does not trip anymore. The circuit board is being powered, the bridge rectifier appears to be doing its job, but the servo motor doesn't spin. The coil of the motor gets warm which tells me its getting power, but it just doesn't spin. I tested the Potentiometer wiring and looks fine, and the Forward/Reverse toggle is fine as well, carbon brushes are fine but I can't find what else could be dead on the circuit board or any other place of the power feed. Any tips/help will be appreciated.
Here's a link to my Onedrive with some Pictures I grabbed from the board:
https://1drv.ms/f/s!Asv5yaQakrNSiMQBsZVmAgEDPQk-SA
Olivier
I have a friend who is an machinist and owns an old Bridgeport mill with an even older Servo Type 100 power feed.
He never installed a limit switch on his power feed and then one day, he turned on the power feed to maximum speed by accident and the mill hit the end, apparently killing the servo because it released some magic smoke.
Since Type 100 circuit boards are pretty much impossible to find nowadays and the type 150 boards are over $100 plus tax and shipping (like this one or this one), I wanted to attempt to repair the damaged board myself.
I'm not an electronics expert but I do have a lot of experience. This is what I have found so far:
When I plugged in the 110v cable of the power feed, the breaker would trip instantly. I opened the Servo unit, I noticed that the circuit board had short-circuited traces right where the 110v lines come in. I repaired the damaged traces and then started diagnosing components. All Varistors are fine (open, not shorted) and I found that the Bridge Rectifier diodes were dead, they had continuity on both directions. I replaced all 5 Diodes (400v 6A) found in the Bridge Rectifier area, replaced a blown 16v capacitor, tested all resistors and all of them appear to be fine.
Now, when I plug the 110v cable the breaker does not trip anymore. The circuit board is being powered, the bridge rectifier appears to be doing its job, but the servo motor doesn't spin. The coil of the motor gets warm which tells me its getting power, but it just doesn't spin. I tested the Potentiometer wiring and looks fine, and the Forward/Reverse toggle is fine as well, carbon brushes are fine but I can't find what else could be dead on the circuit board or any other place of the power feed. Any tips/help will be appreciated.
Here's a link to my Onedrive with some Pictures I grabbed from the board:
https://1drv.ms/f/s!Asv5yaQakrNSiMQBsZVmAgEDPQk-SA
Olivier