[ARC5] BC-454-B, tough problem

[Leslie Smith]

  Some time ago I had a BC-453 that didn't work.  Again the oscillator
  circuit didn't work.  I couldn't find any reason for this.  I
  discussed the problem with a "cluey" telecom tech type, David.  He
  proposed the most bizzare solution.


Go home.  Fold a travelling rug into 4 and put it on the floor.  Hold
the receiver 600mm (David said 2 feet) above the blanket (very square to
the floor) and drop "the thing".  Take care not to damage the
box/chassis by dropping the set on one corner.  I followed his
instruction to every detail and - surprise - found the set worked.


This is a true story in every detail - although you may discount choose
to discount it.
That's all I've got to say.



   73 de Les Smith

   vk2bcu at operamail.com







On Sat, Nov 19, 2016, at 15:19, J Mcvey via ARC5 wrote:

> I had a similar issue a while back. Note that the tuning gang is in
> the oscillator PLATE circuit. It was the the variable cap that was
> bringing down the plate.
> I blew it out with an air compressor to clear the short. 

> It may have been a  growth from the metal or just a stray shard. I
> never saw the culprit.
> 

> 

> On Friday, November 18, 2016 4:54 PM, WA5CAB--- via ARC5
> <arc5 at mailman.qth.net> wrote:
> 

> 

> Not that it would appear to have had anything to do with the problem,.
> but the only lead going through the tuning capacitor covver is the
> mixer grid lead.
>
>  In a message dated 11/18/2016 15:04:18 PM Central Standard Time,
>  ianmwilson73 at gmail.com writes:
>> I've been resurrecting a BC-454; everything worked FB except for the
>> local oscillator stage (triode part of the 12K8 triode-hexode).
>>
>>
>>  The triode plate voltage appeared to be absent. This part of the
>>  circuitry is a little obscure, since there is a 200k plate series
>>  resistor that is contained in the RF oscillator subunit of the plug-
>>  in coil thingy. Also, the plate supply for this stage is routed
>>  through the capacitor cover.
>
>
> Robert Downs - Houston wa5cab dot com (Web Store) MVPA 9480
> 

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