TU-56 capacitor repair (part numbers)

[Tony Duell]

> (And they are relatively expensive.)  Tantalum capacitors will fail
> in a particularly spectacular fashion if reverse-biased.  One day
> when we arrived at work, there was a 3/4-inch hole burned through our
> multi-thousand-dollar prototype PCB, and a charred spot on the
> workbench below it.  Although there was not enough evidence left to
> prove it, we believe that a tantalum capacitor had been installed
> backwards.

May not have been.... I've had tantalum capacitors 'go up' for no good 
reason, they burn spectacularly give off a large cloud of smoke, and 
often the remains on the boasrd is glwoing red-hot at the end. 

When I say 'no good reason', I mean I've had PCBs that have been used for 
say 5 years, then stuck on the shelf for a few months, then they go up a 
day or so after putting the board back in service. 

They certainly weren't fitted backwards.

-tony