[Milsurplus] BC-344D

[mac]

Larry,

Yep, changing out T1 would be a bear.  Instead,  just try connecting a  
100K resistor from the plate of V7 (pin 3) over to B+.  Resistor could  
also be connected across the primary terminals of T1 if these are easy  
to reach.  Only thing you'll loose is audio over to one of the jacks  
on the front panel and to pin H on SO-1.  Ran into the same  
transformer problem in a 342 and this simple fix worked fine.

There also appears to be an error in the manuals concerning the value  
of the cathode resistor for V7.  Schematic and parts lists call out  
250K for R-31 for both the BC-314 and 344, way too large a value for  
the circuit.  However, the resistor in the AVC line filter is also  
labeled R31 and 250K would be OK in that application.  If you check  
your receiver I suspect you will find the V7 cathode resistor to be  
750 ohms, the value used in the BC-312 and 342.  This discrepancy  
appears in both my 1943 and 1946 versions of TM 11-850.

Have fun,

Dennis D. W7QHO
Glendale, CA

***********
On Sep 6, 2010, at 9:45 PM, LARRY D GODEK wrote:

>
> It's ALIVE!!!!  got the beast running the other day.  Works quite  
> well except that the audio is a bit down.  Reason:  the T1  
> transformer in the plate lead of the 2nd detector is open.  No B+  
> getting thru.  Bypassed it and using the 2nd audio output.  Even  
> hear stuff downs below 400 kc in the beacon band but not what it  
> should be.
>
> Need a couple of parts.  No description for the T1 transformer other  
> than Transformer, C-205, Audio interstage, but if you've got one of  
> these things laying around in your junk pile, take a look at it.  If  
> it's any good i'll arm wrestle you for it.  Changing it out will be  
> a bear cause all the wiring is piled up right under it.  Course the  
> transformer is on to of the chassis and the wiring that has to be  
> sorted out is underneath with what looks like "zero length" wires.   
> Ugh!  This particular item feeds J1 and J2, 2nd Audio Phones.
>
> On the CM49 lamps i was inquiring about, if not everyone got the  
> email from Al Klase i believe, they are a #44.  Apparently in his  
> copy of TM 11-850 which is the predecessor of mine that is what  
> shows.  My copy is dated September 1946 and does not show #44 lamps  
> anyplace.  Tidbit of info there.
>
> Another part i'd like to find is the volumn control.  The numerical  
> outer scale on mine is a bit bent and scared so i would like to come  
> up with something a bit better looking.
>
> I'm running mine off of 12Vac and 200Vdc for B+.  Seems to work  
> pretty darned good for an old girl like this.
>
> Larry
> W0OGH
>
>
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