The SPERRY UNIVAC UTS 40 system + 8406 double-sided diskette subsystem : Restoration

Dominique Carlier dce at
Mon Oct 2 13:32:50 CDT 2017

You're probably right, but the work is so massive, and also this time I 
would like to understand and target this breakdown instead of working 
(as usual) in blind mode.
In addition, I do not see the same type of capacitor on the CPU board as 
the one from the subsystem you quote as being known to break down.

Do you think that the small green capacitors here

can be as fragile as this model there?


On 2/10/2017 19:05, Camiel Vanderhoeven via cctech wrote:
> On 8/13/17, 11:15 PM, "cctech on behalf of Dominique Carlier via cctech"
> <cctech-bounces at on behalf of cctech at> wrote:
>> On 12/08/2017 19:35, Al Kossow via cctalk wrote:
>>> the black one in the lower left
>>> it is a tantalum, which are known to short, try removing them
>> Yes ! It was this one that was shorted !
>> I decided in the same way to repair the second disk drive but this time
>> by taking some pictures.
> It would be a good idea to replace all tantalum capacitors; if two
> shorted, chances are others are on their way out soon, too. Sometimes,
> tantalum capacitor failure is paired with a nasty epxlosion that can make
> a mess of things.
> Camiel

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