[time-nuts] Racal 1992

[Joe McElvenney]

Hi,

A year or so back I had an unusual fault on my 1991 (160MHz version of
the 1992). After half-an-hour it would lock-up if you changed any
settings but was okay if you left it alone. Of course, after a cool-down
period, all went well until the next time.

Now for some reason I got it into my head that it was the GPIB board
giving me grief so I put the 10x scope probe on a buss line going to it
from IC18 on the motherboard. Instantly the fault appeared and it then
became apparent there wasn't enough poke to run both the counter and the
few pF of the scope lead.

To cut a long story short, the supply pin was bent under at 90 degrees
so the chip was working without any external power, just on internal
leakages, until it warmed up. Had it been IC18 - good bye Mr. Chips.


Cheers - Joe G3LLV