Electronics > Repair

BNC socket fatigue

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Hi, My Micsig tbook mini gets a lot of use in automotive workshop environments and is starting to have trouble with the BNC female contact being stretched out and making intermittent contact with the probes plugged into it. I stripped it down with the idea I could swap the BNC socket from the trigger output which I never use with channel one input BNC but the amount of heat required to de-solder the body of the BNC from the PCB seems like I will de-laminate the PCB or otherwise melt the insulator in the socket.
 I have a possible idea for "repair", if I can find a BNC with a slightly oversize pin to make an adapter for the socket.
Does anyone know a brand/model of BNC which has oversized pins?

Maybe you can mechanically cut old BNC out of the board, part-by-part, if construction allows that ? Or use 'dremel' ...
(of course in this case you have to buy new part anyway)

OR, if your workshop has such facilities, you can fabricate something out of piece brass with enough temal mass so that it has required holes that match pins on original BNC underneath. Heat it up, fill holes with solder and use it instead of iron to perform quick desoldering job. Maybe seems like one of crazy methods, but why not.
And heating original socket up to let's say 80-100C before doing that will also help a lot.

Wallace Gasiewicz:
Can you put another BNC Female somewhere else on the case?If you can then just put a wire or a short coax from the board to the new connector and leave the old one alone.

I desoldered tenths of BNC connectors from PCBs by keeping outer part of the connector (edge) slightly pushed against surface of heating platform set to 290 to 300 degrees Celsius. Then soldered to other PCBs. Temperature may depend on solder used. Although contact area was very small (thin circular edge), it heated up within minute or two and went out very smoothly, sometimes I needed to pull BNC connector with tweezers to heating platform direction,  and PCB to opposite direction. Plastic material inside connectors not melted, but I often do small repairs and resoldering, so can't guarantee on this. I think connectors probably must withstand 260 deg short term, not sure. I have used this heating platform, but a smaller size (image in attachment). I am sure that with heating gun I would damage PCB, because too much hot air moves around compared to heating platform.
Moreover, I've bought new BNC connectors for repairs few times, and struggled of soldering them for a long time (flux, grinding, 300+ Celsius soldering iron). All problems was gone after using heating platform: I set it to around 200 deg, put all BNCs upsidedown, preheated, and accurately placed PCBs on top of them, so BNC four ground pins and one signal pins inserted in PCB dedicated holes, and used 290 deg soldering iron to solder them one by one while keeping BNC edge pushed against preheating platform. But there was another problem, some LEDs weakly lit up when soldered signal pin of BNC, so there was some ac or dc present between platform and soldering iron, which is not good, and must be careful. Everything worked after repair though.

Preheating is absolutely the way to go.


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