20 Oct
1999
20 Oct
'99
2:17 a.m.
--- Doug Coward <mranalog(a)home.com> wrote:
While the silver oxide is hard to solder to it is conductive and no
problem I've seen using sockets of good quality (some of the RN sockets
were trouble with any part).
FYI: silver oxides are relatively easy to remove.
The H27 was somewhat troublesome with bad clock to the z80 (levels and
ringing). there were several mods from heath on that alone. Then the
drives were not the most relaible and cooling was poor too.
Since it was a kit most of the troubles were soldering related. I've
found plenty of bad sockets on them as well. My solution was to pull the
chips, wash off the flux, run them through the dish washer and then plug
in the chips again and test. Often that meant pulling the socket as the
sockets were intermittent, I solder the part in directly.
Allison
Dave Dameron wrote:
> The bad chips were all made by TI.
I, too, have had bad experiences with 1970s TI chips and pin corrosion. I'm
wondering if that's the problem with my Heathkit H-27 controller. No broken
pins but lots of blackened ones (silver oxides).