[MRCA] BC-348 S-meter modification query?

[John Hutchins]

Ray -
In the manual it talks of placing a 200uA meter at bottom end of the 
volume control in series with the lower leg of the IF DET can.   To 
align the BFO/crystal filter.
I use a 100uA meter jumpered by a resistor.   That works well IMO. I 
placed a  .1uF/25V  to ground. either side of the meter.

Hutch

On 2/19/2014 12:47 PM, Ray Fantini wrote:
> The official CQ Surplus conversion handbook has the S Meter installed  in the screen grid of the second IF amplifier, a circuit that works surprisingly but others had used a 6C4 for inverting the AVC voltage that not quite as good. The S meter in the IF screen is very similar to what they used on the old HRO receivers. Another place where the 6C4 was used frequently is as an audio voltage amplifier to drive the audio output tube but I have found that after changing the audio output transformer to one with a low impedance secondary that there is plenty of audio using the stock circuit. Have also seen the same thing done with 6SN7 tubes. Don't know if it will go thru but will attach a picture from the CQ Surplus conversion manual.
>
> Ray F
>
> -----Original Message-----
> From: mrca-bounces at mailman.qth.net [mailto:mrca-bounces at mailman.qth.net] On Behalf Of D. Platt
> Sent: Wednesday, February 19, 2014 11:18 AM
> To: mrca at mailman.qth.net
> Subject: [MRCA] BC-348 S-meter modification query?
>
> I just received a P-model BC-348 from W3PWW.  Its got an internal a.c.
> supply, an S-meter, and some other wiring changes (which I can dope out OK).  The S-meter circuit uses a jury-rigged 6C4 (pentode).  Before I simply remove that mod, and replace the front panel with a good'n, does anyone have any information of this particular S-meter mod.  I don't want to just go ahead and gut the thing, only to insert a problem.
> Thanks in advance..
>
> Jeep - K3HVG
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