This is a minor issue but is there a cure for excessive 'bouncing' of the S-Meter? It seems to work normally but with say an S9 signal it seems to 'bounce' excessivly. Maybe the AVC is not as Slow as it should be, it is working though, OR is it possible that the Meter itself has lost some of its 'damping' ability?
Paul on the Eastern Shore btw pix of the filter on http://pgerhardt.blogspot.com On Fri, Apr 15, 2011 at 12:00 PM, <[email protected]> wrote: > Send Drakelist mailing list submissions to > [email protected] > > To subscribe or unsubscribe via the World Wide Web, visit > http://mailman.zerobeat.net/mailman/listinfo/drakelist > or, via email, send a message with subject or body 'help' to > [email protected] > > You can reach the person managing the list at > [email protected] > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Drakelist digest..." > > > Today's Topics: > > 1. tr-4c s-meter abnormality and reduced sensitivity (Kihwal Lee) > 2. Re: tr-4c s-meter abnormality and reduced sensitivity > (Garey Barrell) > 3. Re: tr-4c s-meter abnormality and reduced sensitivity (Kihwal Lee) > 4. Re: tr-4c s-meter abnormality and reduced sensitivity > (Garey Barrell) > 5. Case screws for L4B PS? (Rich Hallman - N7TR) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Thu, 14 Apr 2011 11:20:49 -0700 (PDT) > From: Kihwal Lee <[email protected]> > To: [email protected] > Subject: [Drakelist] tr-4c s-meter abnormality and reduced sensitivity > Message-ID: <[email protected]> > Content-Type: text/plain; charset=us-ascii > > My TR-4C's s-meter points to S-9 under no signal condition. Adjusting the > sensitivity and the zero pot won't correct it. I also noticed its reduced > sensitivity compared to other Drakes that I have. The s-meter moves as > expected > when RF gain is lowered. Checked/replaced all tubes. I also checked the RF > gain > pot and it's fine. Resistances and voltages on the V13 12AX7 pins seem okay. > I > would appreciate any suggestions. > > Kihwal, K9SUL > > > > > ------------------------------ > > Message: 2 > Date: Thu, 14 Apr 2011 15:29:04 -0400 > From: Garey Barrell <[email protected]> > To: [email protected] > Subject: Re: [Drakelist] tr-4c s-meter abnormality and reduced > sensitivity > Message-ID: <[email protected]> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed > > Kihwal - > > Check Pin 2 of V17 for resistance to ground (270 Ohms) and voltage ~7.5 VDC. > > 73, Garey - K4OAH > Glen Allen, VA > > Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line > and TR-4/C Service Supplement CDs > <www.k4oah.com> > > > Kihwal Lee wrote: >> My TR-4C's s-meter points to S-9 under no signal condition. Adjusting the >> sensitivity and the zero pot won't correct it. I also noticed its reduced >> sensitivity compared to other Drakes that I have. The s-meter moves as >> expected >> when RF gain is lowered. Checked/replaced all tubes. I also checked the RF >> gain >> pot and it's fine. Resistances and voltages on the V13 12AX7 pins seem >> okay. I >> would appreciate any suggestions. >> >> Kihwal, K9SUL >> >> >> _______________________________________________ >> Drakelist mailing list >> [email protected] >> http://mailman.zerobeat.net/mailman/listinfo/drakelist >> >> > > > > ------------------------------ > > Message: 3 > Date: Thu, 14 Apr 2011 19:15:11 -0500 > From: Kihwal Lee <[email protected]> > To: "[email protected]" <[email protected]> > Cc: "[email protected]" <[email protected]> > Subject: Re: [Drakelist] tr-4c s-meter abnormality and reduced > sensitivity > Message-ID: <[email protected]> > Content-Type: text/plain; charset=us-ascii > > It's 290 ohm and the following are the voltage levels. > pin1 0.2v > pin2 12v > pin5 237v > pin6 246v > > Probably I should check the R's around the meter as the pin6 voltage seems a > bit high. Any other suggestion? > > Thanks > Kihwal K9SUL > > > On Apr 14, 2011, at 2:29 PM, Garey Barrell <[email protected]> wrote: > >> Kihwal - >> >> Check Pin 2 of V17 for resistance to ground (270 Ohms) and voltage ~7.5 VDC. >> >> 73, Garey - K4OAH >> Glen Allen, VA >> >> Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line >> and TR-4/C Service Supplement CDs >> <www.k4oah.com> >> >> >> Kihwal Lee wrote: >>> My TR-4C's s-meter points to S-9 under no signal condition. Adjusting the >>> sensitivity and the zero pot won't correct it. I also noticed its reduced >>> sensitivity compared to other Drakes that I have. The s-meter moves as >>> expected >>> when RF gain is lowered. Checked/replaced all tubes. I also checked the RF >>> gain >>> pot and it's fine. Resistances and voltages on the V13 12AX7 pins seem >>> okay. I >>> would appreciate any suggestions. >>> >>> Kihwal, K9SUL >>> >>> >>> _______________________________________________ >>> Drakelist mailing list >>> [email protected] >>> http://mailman.zerobeat.net/mailman/listinfo/drakelist >>> >>> >> >> _______________________________________________ >> Drakelist mailing list >> [email protected] >> http://mailman.zerobeat.net/mailman/listinfo/drakelist > > > > ------------------------------ > > Message: 4 > Date: Thu, 14 Apr 2011 22:23:29 -0400 > From: Garey Barrell <[email protected]> > To: "[email protected]" <[email protected]> > Subject: Re: [Drakelist] tr-4c s-meter abnormality and reduced > sensitivity > Message-ID: <[email protected]> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed > > Kihwal - > > OK. Most likely problem is a leaky C212. That Cathode (pin 1) voltage > is way too high. the stage is drawing ~42 mA rather than the 28 mA it > should be. Check R185, and disconnect C212. The Cathode voltage should > drop to around 7.5 VDC. R92 is about 7% high, so in tolerance, but ... > I suggest replacing R92 and C135 while you're in there! > > The Screen (pin 6) is also too high, but that may be a function of a > damaged tube from overcurrent. It's possible that you are seeing AC > ripple voltage if the Twist-Lok cap is original. You can check for AC > voltage on Pin 6 with AF GAIN full CCW. If you read several volts AC > here you'll need to replace C145. Replacements for the caps are > available from www.hayseedhamfest.com. > > 73, Garey - K4OAH > Glen Allen, VA > > Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line > and TR-4/C Service Supplement CDs > <www.k4oah.com> > > > Kihwal Lee wrote: >> It's 290 ohm and the following are the voltage levels. >> pin1 0.2v >> pin2 12v >> pin5 237v >> pin6 246v >> >> Probably I should check the R's around the meter as the pin6 voltage seems a >> bit high. Any other suggestion? >> >> Thanks >> Kihwal K9SUL >> >> >> On Apr 14, 2011, at 2:29 PM, Garey Barrell<[email protected]> wrote: >> >> >>> Kihwal - >>> >>> Check Pin 2 of V17 for resistance to ground (270 Ohms) and voltage ~7.5 VDC. >>> >>> 73, Garey - K4OAH >>> Glen Allen, VA >>> >>> Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line >>> and TR-4/C Service Supplement CDs >>> <www.k4oah.com> >>> >>> >>> Kihwal Lee wrote: >>> >>>> My TR-4C's s-meter points to S-9 under no signal condition. Adjusting the >>>> sensitivity and the zero pot won't correct it. I also noticed its reduced >>>> sensitivity compared to other Drakes that I have. The s-meter moves as >>>> expected >>>> when RF gain is lowered. Checked/replaced all tubes. I also checked the RF >>>> gain >>>> pot and it's fine. Resistances and voltages on the V13 12AX7 pins seem >>>> okay. I >>>> would appreciate any suggestions. >>>> >>>> Kihwal, K9SUL >> > > > > ------------------------------ > > Message: 5 > Date: Thu, 14 Apr 2011 22:16:11 -0700 > From: "Rich Hallman - N7TR" <[email protected]> > To: <[email protected]> > Subject: [Drakelist] Case screws for L4B PS? > Message-ID: > <[email protected]> > Content-Type: text/plain; charset="us-ascii" > > What size screws are used in the case for a L4B PS? Just got a nice > amp...but the screws were missing on the case for the Power Supply? > > > > Thanks... > > > > Rich N7TR > > ex KI3V, N3AMK, WB3JOV > > www.n7tr.com <http://www.n7tr.com> > > Telnet: dxc.n7tr.com N7TR DXCluster > > > > > > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > <http://mailman.zerobeat.net/pipermail/drakelist/attachments/20110414/d0963bed/attachment-0001.html> > > ------------------------------ > > _______________________________________________ > Drakelist mailing list > [email protected] > http://mailman.zerobeat.net/mailman/listinfo/drakelist > > > End of Drakelist Digest, Vol 34, Issue 25 > ***************************************** > -- Paul Gerhardt K3PG http://pgerhardt.blogspot.com QRP ARCI 6674 FP 274 _______________________________________________ Drakelist mailing list [email protected] http://mailman.zerobeat.net/mailman/listinfo/drakelist
