[ARC5] BC-348Q CW Oscillator Question

[Leslie Smith]

G'day all,  I'm not familiar with the checking process used by military
services, nor with how many mistakes "got thru".  Is there anyone here
with experience in a military lab/workshop that can comment about the
reliability of the manuals?


73 de Les Smith   vk2bcu at operamail.com



On Wed, Jan 13, 2016, at 16:06, John Hutchins wrote:
>
>
    Gentlemen -
>
>
    Taking a look at the schematic, with the CW switch off,  the plate
    pin resistance to ground should or better be infinite.  Or the
    capacitor (14), or gimmic cap is leaking?
>
>
    I would say the measurement seems right since wiht the switch closed
    there are 1 35K resistor (97-0), followed by 2, 1meg resistors (87-
    3) (87-4),  in parallel to ground, thats ~500K + ,on the power bus,
    that feeds the BFO on off switch.    If pins 2, 6 are shorted on the
    back plug it might be a bit less that 500K - .
>
>
    Hutch
>
> On 1/12/2016 10:33 PM, WA5CAB--- via
      ARC5 wrote:
>> I agree that the Switch-Off
          reading should be quite high.
>>
          The chart doesn't actually say, but did you take your Switch-
          On reading with a dynamotor connected or disconnected?

>>
>>
          In a message dated 01/12/2016 20:29:24 PM Central Standard
          Time, arc5 at mailman.qth.net writes:
>>> If that's what the circuit DC path shows, and
            the CW osc works,I wouldn't worry about it. Probably
            is a typo.
>>>
>>>
            I was never fond of wholesale resistance measurements as a
            troubleshooting tool anyway. Are you just poking around or
            is there an issue with it?
>>>
>>>
            On Tuesday, January 12, 2016 6:50 PM, Mark K3MSB
            <mark.k3msb at gmail.com> wrote:
>>>
>>>
            Gentlemen:
>>>
>>>
            I'm restoring my BC-348Q receiver.   The resistance
            measurements I get for the Plate (Pin 6) of the 2nd Det / CW
            Oscillator tube (V233) are way off.
>>>
>>>
            Table D from AN-08-10-112:
>>>
>>>
            CW OSC OFF:  500K
>>>
            CW OSC ON:   5M.
>>>
>>>
            My measurements:
>>>
>>>
            CW OSC OFF:  Infinite
>>>
            CW OSC ON:   600K
>>>
>>>
>From sketching out the DC circuit path from V233 Pin 6,
            I come up with :
>>>
>>>
            CW OSC OFF:  Infinite
>>>
            CW OSC ON:   567K
>>>
>>>
            I'm wondering if the manual has the values flipped?
>>>
>>>
            73 Mark K3MSB
>>>
>>>
>>>
>>>
>>>
>>>
>>
>>
>> Robert & Susan Downs - Houston
>>
          wa5cab dot com (Web Store)
>>
          MVPA 9480
>>
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