Anyone Familiar with the Bridgeport Power Feed circuit board F-6120?

[tfleming]

Just bought a complete Bridgeport power feed, and I bought it knowing it didn't work. Seller indicated that it worked up until a week ago, then it smoked out of the control panel and quit. Well, I got her open today, and here is what I found:

Here is the board:

Here are the reversing switches, notice the one on the "top" is missing a connection in the middle post:

So, here is the "fried" connector, looks like it came loose and "smoked" on the housing:

So, I can certainly put a new connector on it, and place it back on the post. However, I would like to check a few things out first. Not sure if it smoked anything on the board when it went to ground.......

Any thoughts or suggestions? The power light comes on, but neither direction works on the motor. I get nothing. No hum, no buzz, NADA (but that is without that terminal connected). I guess it won't hurt anything to put the wire back on before I try anything. However, I would think I would get something from the other switch, and it does nothing.

 

[Terrywerm]

I would try a new connector and attach it to the empty post on the switch, but check the rest of it over first. Are there any other empty posts? If not, it's a pretty safe bet that it should connect to that switch. Take a look at the wire length and 'set'. Does the wire seem to have just the right length to attach to that switch and does the wire seem to 'want' to find its own way when connected? I don't know how else to word it, but wires have a tendency to show how how they've been laying for the last umpteen years.

 

[tfleming]

Thanks Terry, yeah, that wire goes there. I did find the high level wiring schematic for that, and the color code on the "fried" wire is for that post, so I know it goes there. I am worried what it might have toasted in the circuit board when it hit the case and grounded. I guess it certainly won't hurt to put a new connector on it and try it. I can get a new board for it, but that is another $300 (ouch). If it is something as simple as replacing a specific resistor or capacitor, I am comfortable doing that (if need be). The circuit board itself, is pretty "old school", so a wee bit of patience with the soldering iron might do the trick!

 

[markba633csi]

If the controller is solid state then a component might be smoked. Are there any fuses in there? Is there a schematic diagram available online?
Mark S.
ps I can help you troubleshoot it and save some $$

 

[tfleming]

 

[tfleming]

If the controller is solid state then a component might be smoked. Are there any fuses in there? Is there a schematic diagram available online?
Mark S.
ps I can help you troubleshoot it and save some $$

Yes, there is a fuse, but it is intact. However, unknown if the seller replaced that when it first smoked. I am certainly going to put a new connector on it, and see if it powers up. From the schematic, the pilot light appears to be at the "front end", so just because that lights when you turn it on doesn't necessarily mean much........and thank you for offering to assist in the diag.

 

[tfleming]

I take it that in the 2nd schematic, the NC and NO are "normally closed" and "normally open" as far as the switches go. Maybe all this puppy needs is to have that connector back on. I'll try that here in a bit. If that works, then "Bob's your uncle"................................if not, then I need to dig a wee bit deeper into this puppy.

 

[Keith Foor]

After reviewing the schematic It looks like that wire is the common power for the directional logic (tells the board which way to spin the motor). It is off the bottom of the main power feed into the board via a bridge rectifier. So, if you understand checking diodes with a multimeter, I would look at the bridge rectifier directly off the 115 volt AC input and verify it's not shorted.
Another way to test this is with a simple inline lightbulb circuit. Connect a 100 watt light bulb in line of the 115 volt AC input and see if it glows brightly or not when you apply power. If there is only a faint or no glow, then the rectifier is most likely ok. If it lights up full brightness then it's most likely shorted.

 

[tfleming]

Thanks Keith, yes, I can check the bridge. I have a full function multi-meter, so I can also check the DC voltage coming out of the bridge as well. Not sure I will make it back into the shop tonight, but I will update this thread after testing.

 

[markba633csi]

Hi Fleming, looks like the field supply might be damaged, let me cogitate for a bit and get back to you
Mark S.