VAX 9440

Eric Smith spacewar at
Sun Nov 11 21:31:13 CST 2018

On Sat, Nov 10, 2018 at 8:55 AM Jim Manley via cctalk <cctalk at>

> It's one thing to replace discrete transistors in our IBM
> 1401, but, it's quite another to desolder and yank various little black
> rectangles off extremely dense circuit boards without destroying anything
> else ... and then solder in a replacement,

Actually that's just as easy as the discrete transistors. You just need a
vacuum desoldering station. I use a Hakko 472D-01, which is great, but
unfortunately discontinued. Hakko's replacement, the FR410-03, is even
better, but unfortunately is twice as expensive (around $950).

Some people are satisfied with the handheld vacuum desoldering irons, like
the Hakko 808 (now replaced by Hakko FR-301). They're OK for some small
jobs, but the handpiece is bulky and heavy, so it's difficult if you have a
lot of desoldering to do, or the density is high so you need careful
positioning. The pencil-style handpiece of the 472D-01 or FR410-03 is
smaller and much lighter.

There are cheap no-name Chinese desoldering stations to be found online. I
haven't tried them, but I've generally been dissatisfied with Chinese
no-name soldering stations.

if you can find one not already
> firmly attached to another board with another kind of failure.

Actually that's ideal, because parting out a non-working board isn't
destroying anything useful, and a vacuum desoldering station allows the ICs
to be removed without damaging them.

However, for rare parts it's more common to not have any other board with
that part, working or otherwise.

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