Repairing Bridgeport servo power feed

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Glenn Brooks
Posts: 2930
Joined: Mon Nov 10, 2014 1:39 pm
Location: Woodinville, Washington

Repairing Bridgeport servo power feed

Post by Glenn Brooks »

My Bridgeport clone Servo 140 table feed(right hand side drive) lost its power cord yesterday. One of the wires pulled loose from the bottom of the housing.

I can’t figure out how to remove the innards without damaging the parts. I loosened the bottom housing. Took out the four screews, pulled the nut off the drive gear on the bottom. The parts assembly seems to be held in the housing by a spring load of some sort. Won’t come out. Even the plastic drive wheel on the bottom won’t come off the shaft when prying with a screw driver. The parts diagram shows a retaining pin and clip mid way into the housing. But no may to access them. Crazy.

Any idea how to take these things apart?

Thanks
Glenn
Moderator - Grand Scale Forum

Motive power : 1902 A.S.Campbell 4-4-0 American - 12 5/8" gauge, 1955 Ottaway 4-4-0 American 12" gauge

Ahaha, Retirement: the good life - drifting endlessly on a Sea of projects....
whateg0
Posts: 1114
Joined: Sat Mar 28, 2009 3:54 pm
Location: Wichita, KS

Re: Repairing Bridgeport servo power feed

Post by whateg0 »

If it's really cloned off of the Servo, once the four screws are out, you can remove the lever then take the name plate off of the front. It had adhesive on mine that didn't do much, but I still took it off. Then just persuade it apart. The gear doesn't have to come off, depending on how your's is assembled. There is a board along the right side of the unit that comes out that has the switch/breaker on it. This video shows disassembly to a degree. You can see the pcb I mentioned.

I just replaced the gear on mine, btw. It was pretty simple on mine. I'll see if I can get the video posted of it, but just remove the nut in the middle, then the gear, hub, etc. should slide off. The gear and hub on the Servo are held in place on a taper by a spring washer and a snap ring.

https://youtu.be/NiLUDtunUPk
Glenn Brooks
Posts: 2930
Joined: Mon Nov 10, 2014 1:39 pm
Location: Woodinville, Washington

Re: Repairing Bridgeport servo power feed

Post by Glenn Brooks »

Thanks. Turns out mine is the old model 90, not a Servo 140. Just found an inspection plate with the model #. Earlier configuration. It has a Rube Goldberg retaining arm inside the housing that bolts down through a side plate to the inside of the housing. This arm was holding the assembly inside the housing. I got it apart, but not sure I can get it back together again. Also can’t get at the wiring harness under the motor, as the motor appears to be pressed onto the shaft sleeve, and somehow pressed into the housing,,, so likely will send off to a shop to repair, or shell out a shop buck ($1k) for a new one.

Much appreciate your assistance.

Glenn

Note- just found a parts diagram on line. Apparently the motor is held in place with 2 machine screws. I am heading back out to the shop to see if I can locate and remove...then soder a new wiring harness. this is why I never learned to do small electric motor repair as a kid. Nightmare on Elm street, every time!
Moderator - Grand Scale Forum

Motive power : 1902 A.S.Campbell 4-4-0 American - 12 5/8" gauge, 1955 Ottaway 4-4-0 American 12" gauge

Ahaha, Retirement: the good life - drifting endlessly on a Sea of projects....
whateg0
Posts: 1114
Joined: Sat Mar 28, 2009 3:54 pm
Location: Wichita, KS

Re: Repairing Bridgeport servo power feed

Post by whateg0 »

You've probably already figured this out, but the bottom gear appears to come off the same way as on the 140. It may be snug, though. I think I had to work at it a little bit after I got the nut off. You can see in the assembly diagram that parts 88-92 are an assembly. This doesn't appear to have changed. Remove the nut (39) annd the whole assembly slides down off the shaft. The upper side of 89 has a groove that engages the pin/key (41), which of course stays in the shaft.

The main switch and cam arrangement is a pretty neat way of using COTS electrical components. It can be a bit of a challenge to reassemble, though. Just make sure that you get the cam oriented right or else, the lever will swing all the way around in one direction or the other, but not activate the switches.

Dave
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