[UK-CONTEST] Cleaning flux off PCBs

[G3SJJ]

OK, thanks to Ian GM3SEK, Dave, G3YMC and Bob 5B4AGN. All very interesting
and useful, and actually a good crossover of ideas.

I've found some nail varnish remover and that has helped to remove most of
the stuff so that I can see if there are any shorts across the very fine
tracks, which is the Sunday evening cure. I was, in any case, thinking of
going to Maplins across town tmw so I will get some Electrolube Fluxclene or
Ultrasolve, whichever they have, or whichever seems better from info on the
can.

Like Dave, I prefer to see no flux, back to my Plessey Telecomms days, when
you had to be "P.O. soldering approved."

Yes, Bob, I thought I might put a quad op amp in to see if I could get any
gain more from the antennas it is switching!!

The main reason for all this is that over the years I have managed to put
several shorts on the output resulting various track repairs and now I
suspect a blown source driver chip UDN2585A, which is supposed to be
obsolete. I have a couple of different sd chips which I want to try.

I have e-mailed Topten for a replacement board and it looks as though they
have now overcome the intrinsic design problem. "We are in the final phase
of bringing a new Source Driver board to market. This one will have
individual output transistors and a thermal fuse for circuit protection."
Assuming direct replacement, I will probably go for a couple of those for my
two units.

Thanks guys, I knew I would get some useful stuff.  Chris G3SJJ