George, A few questions: * Did you verify that the transistor is good? It might be loose as the result of somebody's previous attempt to repair the same problem. I have had bad ones. * When you turn the function switch to standby does the S meter rise to 60 and is the receiver muted? * While monitoring the AVC/AGC line test point does it change as the function switch is moved from ON to Standby? * Have you verified that the bias supply voltage is present and correct? * Does bias voltage appear at the high side of the RF gain control? * Have you checked for continuity and proper resistor values in the vicinity of the RF gain control?
Ken, WA2LBI Quoting George <[EMAIL PROTECTED]>: > > 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/ > ---------------------------------------------------------------------- > ---------------------------------------------------------------------- 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/ ----------------------------------------------------------------------
