From: Garey Barrell 
Subject: Re: [drakelist] Question about SW-4A


Jean-Marie -

I don't have an SW-4A, but according to the manual that does 
seem high, and would cut off the RF and other AGC controlled 
stages.

1.  C76 is most likely either a paper or ceramic capacitor 
rather than electrolytic.

2.  The grids of V4 and V5 show -1.2V, and they are 
essentially connected directly to the top of C76.

2.  The voltage at the "other end" of R55, the 2.2M resistor 
should be about -1 to -2 volts.

3.  If R57 was open or much increased in value, there could 
be as much as -60V on the end of R55.  This would be my 
first check!

A shorted Q4 is also a possibility.  What are the voltage 
measurements on Q4?

Let us know what you find.

73, Garey - K4OAH
Atlanta




CHERRY wrote:

> 
> 
> Hello to the group,
> 
> Could you please told me the how many volt you have on  the C76 ( little
> electrolytic condenser 0.1 MF/ 200VDC on the power board) of the SW-4A.
> I measure -24 volts and I think it is too much.
> 
> Your comments will be greatly appreciated.
> 
> 73,
> Jean-Marie
> R.L. DRAKE VIRTUAL MUSEUM
> WebMaster
> 

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