[MRCA] BC-348 Help

[Ray Fantini]

Great to see positive comments about the J, N and Q being they have always been one of my favorite receivers. Years ago got into a big pissing match over whether the older versions of the receiver superior to the newer versions like the J, N and Q
I always prefer the simple component layout and installation on the later receivers and thought the older version were much more difficult to work on and like much military equipment tended to be over built.
The reality is though that all versions work the same and have the same specifications so other than the later versions being designed more along the lines of a commercial radio or later TV and the early versions being designed along the lines of a standard military radio they were the same receiver.
Would speculate that although the ARC-5 stuff was more plentiful the BC-348 may have and still is the most popular surplus receiver.
The big 8 uf capacitor that was under the dynamotor deck was still in the last BC-348Q I did and after checking it found it to still be good and ended up using it in the AC supply where it was originally mounted.
Often amazed to see sometimes how well some of the capacitors held up with age.  My 1938 HRO RAS still has the original filters in its power supply and after eighty years they still work without issue.

Ray F/KA3EKH


From: mrca-bounces at mailman.qth.net [mailto:mrca-bounces at mailman.qth.net] On Behalf Of DSP3
Sent: Sunday, February 10, 2019 2:12 PM
To: JEFF CICCONE <kg2bz at comcast.net>; mrca at mailman.qth.net
Subject: Re: [MRCA] BC-348 Help


The J, N, and Q used a different type of capacitor for general use.  The other models used the plastic/paper (postage stamp) types for the .05 and .01.etc.  They are not as robust as the later types in the J, N, and Q.  Also the J, N, and Q used a double trimmer in the modules and they don't fall apart.  I just went through a donor R model and found when I gently tried to adjust the capacitors, each and every one slipped back and shorted out.  If you ever see the adjustable part not level with the collar, its cracked, for sure.   The J, N, and Q use a large capacitor for filtering whereas the others use a bank of metal cased .5ufd wired as .5, 1, or 1.5uf.  I have generally found that these hold up well.   If one is going to modify the unit for an a.c. supply, with good filtering, several of these metal caps are wholly unnecessary and can be removed. Finally, the J, N, and Q mount most components where they're used, rather than on adjacent terminal boards..

Jeep K3HVG
On 2/10/2019 12:39 PM, JEFF CICCONE wrote:

Jeep and folks  I have both a 348J and a Q. My Dad had the J squired away in his  uninsulated attic for many years totally original and unhacked sans DM28.  After he passed away in 2012 my Mom  was cleaning out the attic and saved it for me. I found a dynamotor and after much eyestrain from internet schematics, wired it up and the reception and audio was very good after many years storage - what were the caps that were used in the J model?  Jeff
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