Circuit Board repair

[n2ize]

While working on the inner guys of my yaesu FT-470 I noticed a section of the IF connector board that seems to have taken a bit of heat (not from my soldering iron but perhaps a momentary short at some point) which has caused one of the traces on the board to peel from the board and break.

I am wondering if anyone can recommend a fix. I was considering trying one of those silver conductive pens but I am not sure if it can produce a narrow enough trace. real estate is tight on these boards, they are assembled by robots, and traces are very narrow. Another possibility might be to bridge it with a very thin piece of hookup wire running from just before the point where the break starts to a suitable solder connection point on the circuit board itself. I am inclined to try this second method as the silver pen might be too messy on such a narrow trace and might end up bridging components that I don't want bridged. The narrow gauge hookup wire might be better as it is insulated and can be easily removed if it don't wuyk.

Of course any other suggestions of clever ideas are appreciated.

[PA5COR]

I'll go for the (isolated) hookup wire.
If needed glue in place, i have some teflon coated hookup wire just for that.

[n2ize]

I'll go for the (isolated) hookup wire.
If needed glue in place, i have some teflon coated hookup wire just for that.

Yeah, I think I'm going to opt for the hookup wire as well.

[K7SGJ]

I did rework for over 40 years, and I have found that, as noted above, small hook-up is the best bet. I had all kinds of machines, cameras, reflow, etc. and have found a small bridge across the trace is likely to fail. Follow the trace and try to connect the hook-up wire to solid solder pads on both ends. Scratching the "green" mask off and soldering there makes for a lousy connection. Good luck.

[N5RLR]

I'll echo what others have said; go for the wire method. I've literally "stitched" broken PC boards back together this way -- simple solder bridges would have failed in short order.

Do this repair while rested and alert, and doublecheck your work before applying power to the board.

[N8YX]

Another "aye" for the wire.

[kb2vxa]

I used to do board work for a living and we never used insulated wire except where it crossed traces, then we used Teflon tubing. In a cramped space a thin soldering pencil and needle nose tweezers come in handy when you bridge the space with small gauge bus wire. If you clean the ends of the burned trace with the tweezers and apply a drop of liquid flux first, then a dab of solder from the pencil iron while holding the pre-cut bus wire in place with the tweezers you won't have to worry about a poor joint. Oh and BTW, cutting the trace back with the point of an Exacto hobby knife to where it's firmly attached sure helps keeping it from peeling off.

Yup, aye for wire, you'll make a helluva mess with solder blobs.

[n2ize]

Well, in my case with limited soldering equipment and a ultra cramped circuit board and poor eyesight and considering that a fairly long stretch of the trace has dissolved I think the wire would be the best and least damaging of my options. Even then I still have to figure out why the board took enough heat to peel away and break the trace. In short I have to check some nearby components for shorts and test it very carefully when i apply voltage to it.

In any event I'll be buying a new HT so in the event this one turns out to be a total loss at least I'll have another working radio. Besides, this FT470 has been problematic since i bought it. During the days I had it in operation I had to open it and repair it several times and even had to send it back to Yaesu on one occaision. Nonetheless, i'd like to get it working again. This radio does have some sentimental value to me.

[kb2vxa]

"...a ultra cramped circuit board and poor eyesight...
Maybe that's why I no longer do board work? (;->) I hope your vision didn't go to the middle distance like mine did so maybe a lighted bench magnifier would help. Yeah for sure, SOMETHING fried the trace so should the problem remain after the "fuse" is replaced with wire something's gonna give big time. Remember the precious smoke, you can't put the genie back in the bottle.

[KA5PIU]

Hello.

I remember when some old telephone man was complaining about the "tiny wires" inside a 500 series telephone. ;)
But, yes, teflon magnet wire if need be.
I have soldered quite a few hearing aids in my day but now it is all in the ear, very little soldering, the parts are actually held together to work.
Some radios are better than others.
My current ham talkies, the TH-f6a, and VX-3R and VX-7R, have proven themselves over again.
For commercial service we have all gone away from Motorola back to GE, now Harris, and have been tickled pink.
Pull apart any of the ham talkies, the boards are connected with ribbon cable that makes servicing (modding) very easy.