[MRCA] BC-348 S-meter modification query?
Ray Fantini
RAFANTINI at salisbury.edu
Wed Feb 19 13:47:01 EST 2014
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
______________________________________________________________
MRCA mailing list
Home: http://mailman.qth.net/mailman/listinfo/mrca
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:MRCA at mailman.qth.net
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
-------------- next part --------------
A non-text attachment was scrubbed...
Name: smtr.jpg
Type: image/jpeg
Size: 18316 bytes
Desc: smtr.jpg
URL: <http://mailman.qth.net/pipermail/mrca/attachments/20140219/6f82e56d/attachment-0001.jpg>
More information about the MRCA
mailing list