[Hammarlund] Still more bad micas

Tue, 10 Jun 2003 18:21:07 -0400

Years ago I had a BC-348 that had postage stamp caps with color code dots
that looked like mica but were actually paper!

Have you opened one of these caps up to be sure its mica?

Just an improbable thought.

Pat
wa4tuk

> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]]On Behalf Of Phil Atchley
> Sent: Tuesday, June 10, 2003 2:17 PM
> To: [email protected]
> Subject: [Hammarlund] Still more bad micas
>
>
> Hello
> Well, it looks like there are still some more bad mica capacitors in this
> SP-600, this time in the band 4 module.  I am listening to some SSB in the
> 20 meter band and the frequency is jumping around like bands 5 and 6 did.
> To double check I went to the 15 Meter band on band 5 and they are rock
> steady.  Back to 20M and it's jumping around.  So, a little later this
> morning it goes back on the workbench for servicing.  I'll
> probably do band
> 3 at the same time just to be on the safe side.  At least bands 1 & 2 were
> done while I was replacing the BBoD's.
>
> I suspect if one were able to measure gain closely enough a person 'might'
> be able to detect problems in the micas that are in the RF amplifier coil
> modules.  Luckily they aren't as critical and a capacitor would probably
> have to be really bad to cause any problems there.  A one or 2 PF change
> probably isn't going to affect the circuit to any degree.
>
>
> 73 de Phil, KO6BB
>
> ****************************************************
> *  DXing WITH THE FOLLOWING EQUIPMENT.             *
> *  RECEIVERS:                                      *
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> *               Hammarlund HC-10 Sideband adapter. *
> *    Yaesu VR-5000 Wideband, "DC to Daylight".     *
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> *  ANTENNAS:                                       *
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> *    Roof mounted Hustler 6BTV 6 band Vertical.    *
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