[Premium-Rx] Nonsmoking Tantalums

[John Miles]

When you replace these, bump the voltage rating up.  They fail when they
aren't derated sufficiently (e.g., 16V tantalum on +15V supply bus).

They *seem* to be pretty reliable if you double the WV rating.

-- john KE5FX
  -----Original Message-----
  From: premium-rx-bounces at ml.skirrow.org
[mailto:premium-rx-bounces at ml.skirrow.org]On Behalf Of DAVEINBHAM at aol.com
  Sent: Thursday, April 28, 2005 9:58 AM
  To: premium-rx at ml.skirrow.org
  Subject: [Premium-Rx] Nonsmoking Tantalums


  I have replaced a few dozen shorted tantalums in my 6 pack of Racal
RA6790/GM's in last 3 years or so.
  However, only one was a smoker. Mostly they just short and the +15 power
supply shuts down.

  Regards,
  Dave
  **************************************************************************
**************

  Rick,

  You might also check if the power supply has any tantalum capacitors in
it, such as 10uf at 25V match-head epoxy dipped style.  They are sometimes
used as filters on VCC lines, usually downstream from a 10 ohm 1/4 watt
resistor.  I don't know why, but in the last five years I have run into
literally hundreds of shorted ones in Racal, Fluke, Datron and other
equipment.  In all cases they were adept at sending smoke signals.

  The HF-1000 supply sounds almost like a PC power supply...5V, 12V and a
power good signal line...

  Geoff Fors

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