[R-390] Still Deaf below 8 Mc one more question

[Jon Schlegel]

Jim,

I'm new to these receivers but have been familiarizing myself with 
them as I await arrival of the one I have purchased.

A feature of these receivers is that it is double conversion above 8 
MHz and triple conversion below 8 MHz.  Below 8 MHz, an extra mixer 
(called "1st Mixer, V203, 6C4") is inserted into the path after the 
2nd RF stage.  It seems this is the most likely area to look meaning 
V203, V401 and the switching that inserts V203 into the signal path.

In regards to the VFO (PTO), V701, since your receiver apparently 
works above 8 MHz.  It's probably safe to say that the VFO itself is 
working.  The value of 150k is reasonable as a grid leak 
resistor.  150 ohm is too low.

Regards,
Jon



At 04:08 PM 10/27/2007 -0500, you wrote:
>I mentioned in my previous posting Pin 1 of V701 measures 178K Ohms
>and should measure 150K Ohms. I looked at the schematic, and it looks
>to me like this resistance is governed by R701. R701 resistor in the
>receiver was a Brown Green Yellow or 150K resistor. I measured it and
>it measured 178K. Therefore I replaced it with a new resistor that
>measured closer to 150K. Pin 1 now measures 150K Ohms to ground.
>However, tthe DC voltage at Pin 1 remains at around -0.46VDC (should
>be -1.0 to -3.0 VDC according to the manual).
>
>I took another look at the schematic, and on closer inspection R701
>looks like it should be a 150 Ohm resistor. Can this be right? It
>looks like someone forgot to put the K on the resistor value on the
>schematic. Comments?
>
>Jim KG9MM
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