[Drake] Drake R4B Passband Tuning Problem Additional

[Rodger]

Bob,

Also, be sure you correctly adjusted the 5595 Khz. oscillator and the 50 
Khz. IF transformers as problems here will show up when you try to do 
the passband tuner alignment.   Either use a frequency counter or check 
the 5595 Khz. oscillator signal in another receiver to make sure it is 
very close to correct.  Although the 50 Khz. IF transformers tune fairly 
broadly the passband tuner does not so if your mixer oscillator signal 
is wrong this will create a problem when trying to align the final IF.

73, Rodger WQ9E
>
> Bob Scott wrote:
>> I have an R4B that I bought awhile ago and am just starting to look 
>> at.  It seems to have a problem with the passband tuning.
>>
>> If I am reading the schematic correctly, if the passband selector is 
>> in the 4.8 position, the passband tuning circuit is bypassed.  
>> Otherwise, one of the tuned circuits is selected.
>>
>> If I select the 4.8 position, I get lots of signal/audio.  If I 
>> switch to the 2.4 or narrower positions the signal level drops 
>> dramatically.  If I try the passband tuning alignment procedure, I do 
>> not get much of a change in the voltage level at TP-2 which makes me 
>> think there is a problem in that area.
>>
>> If anyone has any experience working on this receiver and can give me 
>> some ideas, I would be grateful.  My electronic skills are a bit 
>> rusty, but I would really like to fix this vs sending it out for 
>> repair/alignment.
>>
>> 73, Bob Scott W4ZY
>> Woodbridge, VA
>>
>>
>>
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>
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