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Bitrex

On 05/02/2016 07:01 AM, wrote:
On Monday, May 2, 2016 at 6:49:30 AM UTC-4, bitrex wrote:

Question is now that I've located the problem, what's the most effective
way to make an expedient repair? I can't seem to get the wire to make
firm contact no matter how I poke at it, and it seems impossible to pull
out of the header.

I'm thinking about just clipping it off, heat shrinking a longer section
to it and then soldering it directly to the underside of the board, but
that seems a bit barbaric.

The solution that I use for this issue, typically, is to strip a small piece of fine gauge (appropriate to the MPC) copper wire -leave it on the spool for leverage - preferably hardened, and I keep a couple of small spools _only_ for this purpose, and push it down the connector beside the broken wire. Touch this wire with a hot iron and a bit of solder to bridge the break, and then cut it off with fine nippers. If the MPC is very fine, I will pre-tin the wire as it may not flow down the hole. If and then, a bit of hot-melt or similar to insulate any exposed wire. Done.

I have been known to use a silver-plated sewing needle, broken off to the proper length if copper would be too soft. They solder very nicely.

Peter Wieck
Melrose Park, PA

OK, so the mystery deepens a little bit. I was having trouble getting
the shimming to work consistently, so I tried jumpering directly from
the control wire to the underside of the PCB.

Turns out that there's still a problem, even with the wire jumpered
directly to the board. But when I pinch the wire junction in my
fingertips, everything works normally.

Pull-up resistor gone open on that line, maybe?