Bridgeport Power Feed 6f Motor Mount Question

expressline99 said:
What's horrible is that there just isn't much too it after the board. I've got new micro-switches. Which I've taken out and tested to insure they work properly. Then set the switches to not over run each other on the direction handle...neutral and so forth. The fuse holder is new. The light is new. The pot is new. I thoroughly tested the pot today. It works fine. I even tried testing it in the balanced state. About 250 ohms each side. Very Even. The motor is basically brand new inside except for the field windings. But that was done professionally. I don't think that would be wrong. Power switch works or the light wouldn't work. Wiring wise it's all exactly as diagrams show me. Down to the pin on the harness everything connects to.

Tomorrow I'll go over every wire in the harness and check for faults there. Grounded and/or no continuity from ends to pins. :( Beyond that I'm back to it being an expensive mystery. If I can't find it I'll have to call Wayne at icai and ask him what he thinks. Maybe it will be obvious to him.

Know anyone that is great at electronics?

Paul
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Are you saying you have a linear pot? My memory tells me that pot should have a logarithmic taper resistance. Was there anything wrong with the original pot? I would use the original pot if nothing is wrong with it and it is just used, a used pot is fine by me. The original pot was also sealed. That kind of pot with mentioned characteristics, design and made in the USA is kinda hard to find today and $. Use the original whenever possible.
 
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In motor speed applications the pots are commonly linear, it is just acting as a voltage divider. The pot is specified as a 2W 500 ohm, Honeywell make decent pots. It could be that the leads to the pot are wired incorrectly. You should be able to check voltages to the motor (90VDC) and the field coil (100VDC), you could do this with the motor disconnected. If you are not getting voltage, then you need work backwards, check the voltage at the control board terminals and then to/after direction switches.

http://www.atechfabrication.com/information/Bridgeport_Feed_Controller.htm
 
chips&more said:
Are you saying you have a linear pot? My memory tells me that pot should have a logarithmic taper resistance. Was there anything wrong with the original pot? I would use the original pot if nothing is wrong with it and it is just used, a used pot if fine by me. The original pot was also sealed. That kind of pot with mentioned characteristics, design and made in the USA is kinda hard to find today and $. Use the original whenever possible.
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The one that was original one got opened/cleaned/destroyed months back. Little did I know. The pot I see online for this is $41.00 so maybe that's the difference? It needs a taper resistance pot? This one for sure is linear I just checked. It's a honeywell 380c1500.

Bob Korves said:
Paul, my thought in my post was not so much about the components, but more about the wiring. Really, it is the composite of all the components and wiring together as a system. I am certainly no electrical or electronic genius. When I tear down electrical wiring, I make a schematic of how it was, and what color wires went to which terminals. I label the connections if they are not already. That way I can put it back the way it was before I started on it. Yes, there may be mistakes, even multiple ones, from the previous owner(s) or builder. The next step is to understand the wiring, what does each wire do, how is it activated or deactivated, and how does everything work together to do what it is supposed to do. Lots of people get overwhelmed by a bunch of different colored wires with no big signs for what each one is and does, seeing the total with glazed eyes. My rule on troubleshooting anything is that I must first understand clearly in my mind exactly how it all works. After that it is a matter of testing things to make sure they are doing what they are supposed to do, and fixing the things that are not correct. We cannot understand why it does not work until we understand how it should work.
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Oh I'm not overwhelmed by the wires. Back when I worked for a sub contracting company for the phone company. I got sent once to find 2 wires in a building that had 2 million coming into it. This was in San Jose. I think the building was #1 1st street? Or something like that. Anyway, the building used to be the phone company way back. So figure a wall 6ft high 50ft long full of 66 blocks. Fed by 1200 wire cable bundles. I was so overwhelmed by that I sat down on the floor and just stared but I found the wires! That's been ages ago.

If it's a log pot and this one is a linear that's got to be it!

Paul
 
mksj said:
In motor speed applications the pots are commonly linear, it is just acting as a voltage divider. The pot is specified as a 2W 500 ohm, Honeywell make decent pots. It could be that the leads to the pot are wired incorrectly. You should be able to check voltages to the motor (90VDC) and the field coil (100VDC), you could do this with the motor disconnected. If you are not getting voltage, then you need work backwards, check the voltage at the control board terminals and then to/after direction switches.

http://www.atechfabrication.com/information/Bridgeport_Feed_Controller.htm
Click to expand...

That's the diagram I've printed and have been using. I'll have to spend some time checking voltages later today. I will do this.
Paul
 
I will trust my memory and still say the pot is logarithmic. Find the actual 6F schematic and or original pot to find out. That schematic you just referenced is too generic. Yes, I know it is a Bridgeport schematic but not in the detail you want. You want the actual schematic of the 6F circuit and its parts list.
 
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My memory was correct. Please look at the pic below of the Bridgeport 6F parts list and #11632618.
pot.jpg
 
I went down this rabbit hole for a while and got very frustrated. Circuit design has been very much improved now. I replaced components and fiddled and tweaked like you before doing the following as done by Atech:
http://www.atechfabrication.com/information/Bridgeport_Feed_Controller.htm

This is an excellent fix and is working flawlessly, I bought a miniatik board on eBay second hand and sold my Bridgeport board for parts at the same price, new micro switches off eBay and some relays too, the repair only cost me about $40.
It works great!


Sent from my iPhone using Tapatalk
 
I personally see no need to do that kind of mod on the 6F. The 8F has some factory changes. I guess the best was the lever direction mechanism change on the 8F. Anyway, if a few problems are taken care of correctly, both 6F & 8F are the best feed IMHO…Dave
 
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