[Milsurplus] BC-348-Q restoration

[Joe Connor]

 Thanks, Mark. That's great information to have.
                     Joe Connor
    On Monday, June 15, 2020, 10:36:37 PM EDT, Mark K3MSB <mark.k3msb at gmail.com> wrote:  
 
 Well,  my web site had the detailed pictures of the 4 modules but nothing about their removal.   So,  after working 8 hours and spending 3 hours on yard work,  I did some fast scrambling and updated my web site with some removal notes.   First pass,  but if I didn't get this up tonight it would probably fall off the radar....   I will try to align my terms with those in the manual at a later time.    Comments welcome.   

http://www.k3msb.com/bc348/main.html
Scroll down and select the link for "Antenna / RF / Detector / Oscillator (sub)Assembly Photos"
73 Mark K3MSB




On Mon, Jun 15, 2020 at 8:22 PM Dennis Monticelli <dennis.monticelli at gmail.com> wrote:

OK.  Found another mod.  This one was hidden behind the front access plate.  The first RF stage 6SK7 had been rewired as a pentode. I'm thinking there must have been a published mod way back when on getting more gain the easy way.  Stock is triode connected.  I presume the designers chose a triode for lower noise.  Meanwhile the impedance matching to the next stage and the overall gain distribution is all tied to that triode connected stage.  Unless someone tells me otherwise, I will reverse the mod.
Dennis AE6C
On Mon, Jun 15, 2020 at 8:00 AM Dennis Monticelli <dennis.monticelli at gmail.com> wrote:

Hi guys,
I am beginning my first BC-348 restoration. Luckily the Q model is the simpler of the two basic types. It appears to have decent caps, not micamol. Not badly hacked either.
First order of business has been to remove unwanted mods. That means all other than the AC supply, which fortunately was well executed.  A 1uF bypass cap on the cathode of the 2nd IF has been added.  The stock 0.1uF bypass is still there.  Was this a published mod to change AVC action?
Regarding the tuning gearing.  It was stiff and I found dried grease.  Was any grease used on stock units?  I note the use of brass on steel gear design choices which I recall is naturally lubricating.  What do you recommend regarding cleaning and possible lube of the gears?  I am using WD-40 on Q-tips to clean off the old lube.
Any other restoration hints would be appreciated.
Dennis AE6C
______________________________________________________________
Milsurplus mailing list
Home: http://mailman.qth.net/mailman/listinfo/milsurplus
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Milsurplus at mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
______________________________________________________________
Milsurplus mailing list
Home: http://mailman.qth.net/mailman/listinfo/milsurplus
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Milsurplus 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 --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/milsurplus/attachments/20200616/68c24df1/attachment.html>