Hi all went through it and found the transistor on the agc board was loose resoldered and went to readjust the bias and s meter. I turned the rf gain fully counterclockwise and it would not move the s meter to 60 like it did before and was bouncing around. still no agc action.....
George ne2i ----- Original Message ----- From: "Ken, WA2LBI" <[EMAIL PROTECTED]> To: "George" <[EMAIL PROTECTED]> Cc: <[EMAIL PROTECTED]> Sent: Friday, April 09, 2004 4:04 AM Subject: Re: [drakelist] R4A AGC inop. > > George, > > Since this receiver is new to you don't overlook the possibility of MULTIPLE > problems. I serviced a R-4B last year that had similar symptoms, among others, > to yours and it turned out to have several bad tubes and resistors. Of course I > had swapped tubes in order to isolate the problem but I was actually swapping > one bad tube for another! Talk about chasing your tail! > > Have you checked all the voltages and resistances against the corresponding > charts in the manual? That is a good place to start with a new rig with an > unknown history. > > Keep us posted on your progress. > > Ken, WA2LBI > > Quoting Garey Barrell <[EMAIL PROTECTED]>: > > > > > George - > > > > OK.. > > > > Measure the voltage at TP-2 (on top of the chassis, just in > > front of the Passband tuner.) Should measure -1.35 volts > > with the the Preselector detuned on any band. > > > > Have you tried both Fast and Slow AVC? If no AVC in either > > position, try swapping the Calibrator tube, 12BA6, with > > either of the IF tubes, V4 or V5. Something is loading the > > AVC line. If this doesn't help, try swapping the RF Amp, V1 > > with another 12BZ6. > > > > Beyond this, you'll have to find what is either loading or > > shorting the AVC line. Possibly one of the grid resistors > > of V1, V4 or V5 cracked or open. They can go up in value > > considerably without affecting the AVC, so unless they are > > open, look elsewhere. > > > > Let us know what you find. > > > > 73, Garey - K4OAH > > > > > > > > George wrote: > > > > > To add to that it is an 11 tube model (no 12av6) > > > > > > George NE2I > > > ----- Original Message ----- > > > From: George > > > To: [EMAIL PROTECTED] > > > Sent: Thursday, April 08, 2004 9:00 PM > > > Subject: [drakelist] R4A AGC inop. > > > > > > > > > Just bought an r4a and it seems like the agc is not working at all > > > I have to ride the rf gain or I get way too much audio and distortion > > > It has good sensitivity and is spot on frequency wise. > > > > > > Also when I select NB or cal the s-meter pegs and I dont get any audio. > > > > > > Thanks > > > George NE2I > > > > > > > > ---------------------------------------------------------------------- > > Submissions: [EMAIL PROTECTED] > > Subscribe: [EMAIL PROTECTED] - subscribe drakelist in body > > Unsubscribe: [EMAIL PROTECTED] - unsubscribe drakelist in > > body > > Hopelessly Lost: [EMAIL PROTECTED] - help in body of message > > Brought to you courtesy of TLCHost.net http://www.tlchost.net/ > > ---------------------------------------------------------------------- > > > > ---------------------------------------------------------------------- > Submissions: [EMAIL PROTECTED] > Subscribe: [EMAIL PROTECTED] - subscribe drakelist in body > Unsubscribe: [EMAIL PROTECTED] - unsubscribe drakelist in body > Hopelessly Lost: [EMAIL PROTECTED] - help in body of message > Brought to you courtesy of TLCHost.net http://www.tlchost.net/ > ---------------------------------------------------------------------- ---------------------------------------------------------------------- Submissions: [EMAIL PROTECTED] Subscribe: [EMAIL PROTECTED] - subscribe drakelist in body Unsubscribe: [EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost: [EMAIL PROTECTED] - help in body of message Brought to you courtesy of TLCHost.net http://www.tlchost.net/ ----------------------------------------------------------------------
