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I have acquired a TMCC BPC.  Investigating the device, I found that someone in their infinite wisdom either broke or clipped the two leads where the shorting block would normally attach. Hence it is in a permanent state of "programming".  If some one could resolve as to why some one would do this, it would remove some of my angst.

That having been said, It was given to me gratis so "no real harm, no foul".  I would like to try a repair.  I have never worked directly with a real PCB only the design on paper.  I have some soldering ability but I am not sure what further damage I could do or if it is even possible to repair as if I remove the solder on the board will I damage because of excessive heat other components.  I would like to think I could apply heat to the solder where the leads go into the board and extract the remainder of the lead(s). Then reheat the area and through trial and error locate the hole where the lead(s) go and reinsert.  A question I have regarding this process.  How do I know if the solder made a connection to the ground plane that I am assuming is imbedded in a layer in the PCB?  Any other issues that I should be made aware of in performing this surgery would be helpful or If you can suggest a better plan than the one I have come up with, I would appreciate your insight.  I do have a variable temperature solder station and if need be I can get access to a solder sucker.

Thanks in advance for your help and suggestions.

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It should not be any issue to replace the jumper, it would seem to be a fairly simple soldering job.  Note that you should have rosin core solder and the proper soldering iron to be attempting this repair.

From the position of the jumper, I'm guessing it may have simply gotten broken off in handling at some point.

Last edited by gunrunnerjohn

As I mentioned I have a variable temperature solder station.  Do you have any suggestions as to what temperature to use?  Also I am aware of the differences between rosin an d acid core solder and when to use one and not the other.  And to my other question regarding connection to the ground plane, since I do not have access to a flow soldering setup, can I be sure that the solder will connect the new lead to the inbedded ground plane?

Use rosin core for electrical soldering. Your question about ground plane confuses me. Heat the remaining pins as you said and remove them and solder wires into those two holes. You could also just solder tack wire to the remaining bit of the pins if the pins don’t fall out of the holes when you try that.

cjack posted:

Use rosin core for electrical soldering. Your question about ground plane confuses me. Heat the remaining pins as you said and remove them and solder wires into those two holes. You could also just solder tack wire to the remaining bit of the pins if the pins don’t fall out of the holes when you try that.

Yes, I understand to use Rosin Core as the Flux medium.  My assumption is/was that one of the layers to the PCB is a "Ground Plane" where all the grounds for the board are connected to.  In looking at the board it appeared to me that this "Ground Plane" is imbedded in the board and I further assume that one of the leads that was clipped goes to this "Ground Plane" since I see no etching going to the solder point.  Therefore assuming my assumptions are correct (and I am looking for a response that says yes the Ground Plane is imbedded or I am mistaken) one is not really sure if the solder applied to the top or solder side of the board will make a good connection internal to the board.

To your suggestion of tacking leads on to the remaining pins, I am wondering what temperature to use on my solder station so as to create little if any more damage due to excessive heat.  Not really knowing what type of solder was used (Lead to Tin percentage) for instance or whatever combination is used now-a-days, it would be to my advantage to know what temperature to start with.

You probably won’t see any trace leading to the ground connection, but the pad the pin is soldered to is plated thru the hole and will make a ground connection just by soldering to the pad. I use a rather high temperature and get off the pad quickly after the solder flows. I generally use about 750 deg F or so. The 63/37 solder flows at about 350 F. 60/40, a little higher. The solder flows very fast and the heat doesn’t have time to conduct very far to other parts of the circuit. 

gunrunnerjohn posted:

I personally use 650 with my Hakko soldering station, and for delicate parts, I drop down to as low as 550..  I've never had an issue with heat, and I've soldered thousands of connections.  I don't recommend higher heat as even a brief high temperature can lift traces and/or separate feed-thru plated holes.

Hi John,

If a trace is lifted on a board but is still connected on one end, can / should you glue it down with Super Glue? This happened to me. I pushed it down, finished the rest of the work and left it alone. The circuit still worked. I'm just curious.

George

gunrunnerjohn posted:

I personally use 650 with my Hakko soldering station, and for delicate parts, I drop down to as low as 550..  I've never had an issue with heat, and I've soldered thousands of connections.  I don't recommend higher heat as even a brief high temperature can lift traces and/or separate feed-thru plated holes.

I’ve lifted a pad or two, but not lately. I was thinking that the plated thru holes might have made that less possible. But I may cut my temperature by a 100 and see how it goes just to be safer.

cjack posted:
gunrunnerjohn posted:

I personally use 650 with my Hakko soldering station, and for delicate parts, I drop down to as low as 550..  I've never had an issue with heat, and I've soldered thousands of connections.  I don't recommend higher heat as even a brief high temperature can lift traces and/or separate feed-thru plated holes.

I’ve lifted a pad or two, but not lately. I was thinking that the plated thru holes might have made that less possible. But I may cut my temperature by a 100 and see how it goes just to be safer.

I'm sure the heat had something to do with my issue, but it only occurred in one spot during desoldering. It lifted as I was trying to get the component off the board. The component was holding tight to one end of the trace. It all worked out, but just a little harrowing.

George

My iron is a very cheap Radio Shack model and not adjustable. I don't do a ton of electronics work. It needs a new tip, and Amazon wants $8 plus shipping for the tip! (not Prime eligible)

I like the high heat, but have been more careful about reducing the time the iron is on the component lead. In any situation, I would think you wouldn't apply the iron longer than it takes to melt the solder. 

George

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