Darnit! UDA50 problem.

From: Tony Duell <ard_at_odin.phy.bris.ac.uk>
Date: Tue Nov 4 11:03:25 1997

On Tue, 4 Nov 1997, Tim Shoppa wrote:
[NPG jumpers]
> 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...

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.

> Tim. (shoppa_at_triumf.ca)

Received on Tue Nov 04 1997 - 11:03:25 GMT

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