Hope someone can help me with this one if possible please .This is the control unit for the power feed on a bridgeport milling machine the resistor on position 61 has blown I’ve tried to remove it off the board and it just fell to pieces I was unable to read the value with a multimeter and it was burnt beyond recognition.

 

Welcome to AAC.

My Bridgeport has Servo power feed, circa 1985. It might help if you can identify the year, make (Bridgeport?), and model number of the power feed. There are so many of those machines that one needs a way to limit the search.

Is that a solid wire between the two pads? If you unsolder one end, what's it resistance?

 

No, there's no wire there
If R61 has died so completely there's obviously a major fault with the board. Just replacing it is unlikely to fix the problem.
Looking in close up there are a number of parts there that are not looking very happy....

 

Try Model Engineers Workshop (MEW).
https://www.model-engineer.co.uk/
Good luck..

 

Sorry, the line on my screen was so bright, it looks like reflections from a wire.

The heavy work is being done by the things on the heatsink. Probably SCR's or Mosfets. Do any look bad? Do any traces to those items look overheated (discoloration bubbles in the conformal coating).

In a different type of controller, I had a single SCR bring the whole thing down. It was an easy fix. I your case, that burned resistor may well be connected to a bad device on the heat sink.

 

Hi Barry,

Just wondering if you were able to fix this issue. I have the exact same board and the exact same resistor is burnt. If you were able to fix it please let me know, as there is so little information available online.

Thanks