4 Nov
1997
4 Nov
'97
3:03 a.m.
On Tue, 4 Nov 1997, Tim Shoppa wrote:
[NPG jumpers]
I'll remind you of that next time you're sitting alongside a fully stuffed
BA11-F trying to remove an NPG jumper from the middle of a DD11-D
backplane :-). It's a lot easier to dike it out.
And even if you do manage to remove it, you have to put the replacement on
top of the other wires - you can't re-wrap it in the same position. I
still think this jumper should have been fitted _after_ the other wiring.
I've often seen DEC field maintenance droids use
the little 0.1" header
jumpers while debugging backplanes. You have to bend the pins to install
one, and they are hardly very permanent, but they do work in a pinch.
Other workarounds include two barrel-type header connectors with a short
piece of wire soldered between them.
Hmmm... While such kludges may be great if you need to quickly try a
machine with a board removed, I'd rather use a proper soldered or wrapped
jumper in a machine I was trying to use. After all, the tool needed to do
the job properly is not expensive, and it's useful for a lot of other
repairs as well.
Why kludge when the proper repair is easier and quicker?
For some crazy
reason DEC fitted the CA1-CB1 jumper before they put the
other wires on those pins. So you have to cut it - you can't unwrap the
old jumper, alas.
If you expend a little effort, you can usually unwrap it. This is what
dental picks and very narrow needle-nosed pliers are needed for...
Tim. (shoppa(a)triumf.ca)
-tony