[Elecraft] Low voltage on AGC threshold

[Mike, W8ENG]

John,   My DMM is a $30 Radio Shack unit.  I do not have anything handy to
calibrate or check the accuracy.  It does report DC voiltage to 2 decimal
points, but I doubt that it is that accurate.  Any way, for now I'm
proceeding with construction.

Mike, W8ENG


----- Original Message -----
From: "John R. Lonigro" <johnlon at sbcglobal.net>
To: "Mike, W8ENG" <w8eng at arrl.net>
Cc: <elecraft at mailman.qth.net>
Sent: Tuesday, November 16, 2004 10:29 PM
Subject: Re: [Elecraft] Low voltage on AGC threshold


> Mike:
>
> How accurate is your DMM?  The 8v and 5v regulators should still produce
> 8 and 5 volts even with a slightly low supply voltage.  Also, if the
> K2's internal voltmeter reads the same as your DMM, that tells me your
> DMM is reading low because there is a diode in the K2 power line which
> will make the K2 internal voltmeter read LESS than an accurate external
> DMM.  Only if the external DMM reads low would the two voltmeters agree.
>
> Try to check your voltages with a different DMM.  My guess is your
> problem is NOT low voltage all around.  Good luck.
>
> 73's
>
> John AA0VE
>
> Mike, W8ENG wrote:
>
> >This is an update to my earlier post.  I touched up a solder joint and
> >reassembled the radio.  The voltage on pin 5 of U2 was still 3.78 volts,
> >with the RF gain set fully clockwise.  The input voltage from my power
> >supply was 12.4 volts, both on my DMM and on the K2's internal voltmeter.
> >The voltage out on the 8v regulator was 7.8,a nd on the 5v regulator was
> >4.9.
> >
> >I'm thinking that the problem may be low voltage all around.  I don't
have a
> >better power supply to check with at a higher voltage.
> >
> >Any addational help or comments would be appreciated.
> >
> >73,  Mike, W8ENG
> >
> >
>