[Packet] fpllow up to question on KPC-2

[Dr. Gerald N. Johnson]

On Tue, 2006-09-26 at 15:27 -0700, kd7nm wrote:
> This is a fairly common problem where inexpensive capacitors
> are used as part of a DC/DC converter to generate a negative
> power supply from a positive power supply, as for RS-232
> interfaces, and some modem chips.  Unless the capacitors
> have a low effective series resistance (ESR), they heat
> internally and dry out.  And I'm sure it was exacerbated by
> the heating from the 7905 VR.  That, and a KPC-2 isn't a
> spring chicken any more!
> 
> 73, Bob, KD7NM
> 
Miniature electrolytics have not been the epitome of a quality
capacitor, even when new. Their aging rate is fast enough to expect more
failures even if not mistreated by external heat or reversed polarity.
-- 
73, Jerry, K0CQ,
All content copyright Dr. Gerald N. Johnson, electrical engineer