Mike , Typing error in my post, last line. Low voltage should be 2.600 not 2.667 - same as you get. Sorry. 73, Geoff GM4ESD
----- Original Message ----- From: "Geoffrey Mackenzie-Kennedy" <[EMAIL PROTECTED]> To: "Mike, W8ENG" <[EMAIL PROTECTED]> Cc: "Elecraft Discussion List" <[email protected]> Sent: Wednesday, November 17, 2004 10:53 AM Subject: Re: [Elecraft] Low voltage on AGC threshold > Mike, > > There is a design problem in this circuit, IMHO, which has to do with > tolerances, and I am having an off list discussion about it. Nothing > serious, and I am sure that it can be fixed easily. I'm letting you know so > that you don't damage anything by too much poking around in K2. The 3.78 > volts that you read at U2 pin 5 is 0.053 volts higher, I figure, than you > should get with the 7.8 volts from the 8v regulator, if the RP6 resistors > are 5100 ohms +- zero!! Three terminal voltage regulators also have > tolerance specs on voltage output as measured at the regulator output > terminal, so 8.000 volts is not a sacred cow. > > I had exactly the same sort of problems, slightly different voltages. But K2 > was VERY useable with AGC on, but not quite up to full sensitivity being a > little bit "AGC limited". > > 73, Geoff GM4ESD > > PS : The low voltage that you get is 2.6 volts - I figure that you should > get 2.667 volts - nit pickey fussy eh? > > > > ----- Original Message ----- > From: "Mike, W8ENG" <[EMAIL PROTECTED]> > To: <[email protected]> > Sent: Wednesday, November 17, 2004 12:44 AM > Subject: Re: [Elecraft] Low voltage on AGC threshold > > > > 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 pow _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
