[time-nuts] GC-1000 Clock Cap Choice?

WB6BNQ wb6bnq at cox.net
Mon Jan 17 01:41:13 UTC 2011


Brooke,

WTF !  Just replace them with the same type as was in there.  That will give you
another 20 or so years and by then you will be dead and won't give a damn.

The only "critical" (for that time) component would be the TC loop capacitors for
the 567 PLL's.  They should be silver mica types (good enough tempco for the
567's), but knowing heathkit they might have just used common disk ceramic types
(bad for tempco).

All these other people going crazy with all the {RE} engineering crack me up.  No
thought as to what is really needed to fix the item.  All they truly do is create
a given level of noise that exceeds the original expectations of this list.

Well, one other thought . . . . . but I would hate to accuse you of trolling,

73....Bill....WB6BNQ

Brooke Clarke wrote:

> Hi:
>
> More than half the electrolytic caps in this Heathkit GC-1000 Most
> Accurate Clock are bad and I'm trying to come up with modern replacements.
> http://www.prc68.com/I/HeathkitGC1000.shtml#Rx
>
> The Tone Decoder board uses a couple of NE567 PLL ICs to capture the 100
> Hz and 1000 Hz WWV tones.  Heathkit used Tantalum caps for the PLL
> output filter.  I'd think something like a low loss electrolytic or
> plastic cap would be better.
> http://www.prc68.com/I/HeathkitGC1000.shtml#TB
>
> Also how about using Aluminum Organic Polymer caps (where there are
> replacements) instead of the plain electrolytic caps?
> The plan is to replace all the electrolytic and tantalum caps since the
> ones that are now OK may fail in the near future.
>
> Any thoughts?
>
> --
> Have Fun,
>
> Brooke Clarke
> http://www.PRC68.com
>
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