George, Gary's advice is sound. I would add that you should review the alignment instructions, particularly Paragraph "J," "Bias and S-Meter Adjustment." I have found these controls to be badly misadjusted in several Drakes in the past. Follow the instructions carefully - especially the identification of the components. Past users may well have cranked on the interior "receiver sensitivity" control blindly (common). Make certain you are operating the radio correctly (RF gain max, etc) with a correctly zeroed S meter.
The other previous remarks regarding bad tubes, resistors, etc are correct. Also - if all else fails - check the fixed and variable resistors in the AGC/S meter circuit, including R89 and R41. I have found resistors in this circuit way out of tolerance, making the required adjustment impossible. Also - performing a complete alignment, especially the tricky passband tuner alignment (Para "I.") will do wonders for these receivers if they have sat around for 20 or 30 years without a careful service (common). 73, Rocco N6KN ----- Original Message ----- From: "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 > > >> > > > > > ----- Original Message ----- > > From: George > > > > 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/ ----------------------------------------------------------------------
