[sdiy] PCB layout mistake = Aaron curls up in a ball in the corner and cries

[Ian Fritz]

Similar to John, I'd bend the pins up and cross wire them to the pads with 
fine wire.  I usually ... um, I mean *if* this ever were to happen to me, 
I'd use #28 wire wrap wire. Since the wire is short it will be quite sturdy 
(think length to thickness ratio).  I don't see any issues with stability 
doing it this way.

   Ian



At 10:12 AM 6/20/2009, Aaron Lanterman wrote:
>Feeling overly confident from the success of my Music Easel LPG layout
>(youtube video to come when I get around to it), I was really excited
>when five new boards (preamp & env det, pulser, envelope generator,
>timbre circuit, and balanced modulator) came from PCBCART last week,
>and I happily built, built, and built. I need to order a few strange
>resistor values and various pots, but I'm close to being able to start
>testing everything.
>
>Then, while viewing the schematic of the timber generator, I realized
>to my horror that I had the +/- on four op amps switched. The feedback
>was going the wrong direction. How could I have not seen that before
>in all the time I've spent staring at the schematic? Hmm, I'll need 8
>jumper wires to fix that. Bad, but still doable.
>
>Then I reviewed the others. The pulser, envelope generator, and preamp
>& envelope detector have op amp inputs OK. But on the balanced mod -
>oh hell, I screwed up the inputs of 11 of the 12 op amps. Aaack, that
>would require 22 jumper wires! *hits head repeatedly into wall*
>
>What makes it worse is I have a vague recollection of actually
>switching the op amps from the correct way to the wrong way at some
>point in a severe brain fart moment.
>
>AAAAAAAAAAAAAAAAARG!
>
>That's a couple hundred down the drain.
>
>I figured it out before I started testing, but I still have most of
>the parts in. My plan is to solder in the vactrols with only a few
>leads in, so I can clip them back out and reuse them (I can't imaging
>committing 7 expensive vactrols to a board that requires 22 jumper
>wires, which I can't imaging are very stable).
>
>But I do want to try to test everything, so that when I fix the op
>amps I can fix other mistakes I find to.
>
>So what's the best approach to actually getting a prototype running?
>
>1) I was thinking of dremelling the traces, but then I thought a
>quicker solution would be to just clip the input leads on the ICs
>where the ICs meet the board.
>
>2) If I take approach 1, is there a "best practices" for soldering
>jumper wires on top of ICs? I imaging it will be hard to make a stable
>connection
>
>3) Instead of 1 and 2, maybe I should unsolder the op amps (I
>generally solder chips straight into the board without sockets, unless
>it's a particularly expensive chip to replace, or failure prone like
>CMOS), put in sockets, and build some "pin switchers?"
>
>- Aaron
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