Hi to Garey and all, Does the egg on my show too much? I saw in the manual that the 12AX7 was used as the keying oscillator, so I swapped it with the other 12AX7 in the transmitter....not to bright.....they both had super low emission! Less than one third spec according to my emission tester!
I stuffed in a couple of somewhat weak 12AX7's that I had in the junk box and the problem is fixed! Will order a new pair and some spares tomorrow. It now runs down to under 104 volts and still can archive full drive! Garey you sure hit the nail on the head....and me too! I guess substitution with a tube unless you KNOW its good is really asking for it! Thanks ever so much for your help. 73's to all, Mark W1MJG -----Original Message----- From: Garey Barrell [mailto:[EMAIL PROTECTED] Sent: Monday, July 21, 2003 11:34 PM To: [EMAIL PROTECTED] Subject: Re: [drakelist] T4-XC /AC-4 low voltage problem Mark - I haven't run into this specific problem, but a couple of the symptoms you mention are related to the Mic Amp stage V9. The Mic Amp is connected as an audio oscillator for the TUNE and CW modes. It provides the "drive" in TUNE and CW Sidetone in CW as well as holding in the relay on CW. Have you tried a new 12AX7 at V9? Emission falls off fast with low filament voltage in a weak tube. Most of us have the problem of too HIGH a line voltage! A SOLA constant voltage transformer would help, but it sure seems like a supply rated at 120V should work over at least a range of +/- 10%, which "should" take you down to 108. I'd be interested in your findings. 73, Garey - K4OAH Atlanta ----- Original Message ----- From: "Mark J. Giubardo" <[EMAIL PROTECTED]> > Sorry this is so long, but has anyone had trouble with a T4-XC/AC4 like > this? > > By the way, the ripple in the high and medium B+ is well with in Drakes > specs. > > Thanks in advance for any help, > Mark W1MJG > ---------------------------------------------------------------------- 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/ ----------------------------------------------------------------------
