[Milsurplus] BC-348R Oscillator Issue output Frequency is 0 for part of band 4 : 6 - 9.5 MC

[hwhall@aol.com]

That's an unusual approach to aligning the tuning.  Are you quite sure the freq counter isn't loading down the oscillator output & sometimes just killing it?

Wayne
WB4OGM

On Thursday, August 21, 2025 at 05:47:35 PM MDT, jphutch60bj <jphutch60bj at gmail.com> wrote: 

Reading the Manual TO-12R2-3BC-112, Revised 15 April 1957,  Page 4-3 paragraph 'e'.

On the four lower frequency tuning bands the
oscillator frequency is higher than the desired signal
by the intermediate frequency. On the two higher
frequency ranges, bands 5 and 6, the oscillator is on
the low frequency side of the desired signal. The latter
results in a more uniform tuning ratio over these
bands and increases the image rejection ratio.

Before I start doing Brain surgery on BC-348R by pulling the RF Units .....

I was Checking Oscillator output frequency with a frequency counter, tweaking the outputs from the oscillator on each band.

Band 4, frequency range of : 6 - 9.5 MC,  reading the manual the Oscillator High Side output should be between 6.915 - 10.415 MC  for band 4?

My Oscillator goes dead no output,  between DIAL Frequency reading of:  7.2  to 8.8 MC - which equates to an Oscillator output frequency of  "+.915"  should be between  8.115 - 9.715 MC.

Issue the output Frequency goes to 0 as measured  on Pin 8, VT-91, 6J7.

If the manual is not wrong,  why is the oscillator output dropping to 0, on this one band?

It aint the tuning cap!-} , as there are no problems with other bands.


Thanks for you thoughts in advance.

JPHutch









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