OK I got the 'spare' PTO out to test and it has a loose 'tuning shaft' The tuning shaft is loose from the 'fork' piece. It appears as though someone had tried to solder it on to the fork piece. Was it orginally a 'press' fit? Has anyone ever repaired this problem before.
I posted of pix of the Assy on my blog at pgerhardt.blogspot.com . It is marked as a T4XB unit. After fixing the shaft to the fork I would like to test it for operation on the bench. I see a ground wire (green black) and another wire a red white). There are also two solder lugs one near the white red wire and another at one of the spring clips. How much voltage should I put on the PTO to check the oscillator? There is also some small amount of grease on the gears but it feels 'OK' turning. I will probably just brush off the gears with an old toothbrush and getting them as dry as possible. Is any thing else recommended? On Thu, Nov 3, 2011 at 8:34 AM, <[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. R-4B Mod removal, Part 1 (Steve Wedge) > 2. Re: R-4B Mod removal, Part 1 (Pete Juliano) > 3. Re: R-4B Mod removal, Part 1 (Steve Wedge) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Wed, 2 Nov 2011 20:37:37 -0400 > From: "Steve Wedge" <[email protected]> > To: "Drake List" <[email protected]> > Subject: [Drakelist] R-4B Mod removal, Part 1 > Message-ID: <9DD85426922D4916BD0A771394E465AA@Shack7> > Content-Type: text/plain; charset="iso-8859-1" > > I'm not as brave as Pete (N6QW) - if I assume that he restored his R-4B all > at once. Chances are, he didn't, but he did give me a darn good road-map. > My first goals for this evening were to check to see if Radio Shack really > did sell long-shafted 10k pots anymore - they do (!) and so I parted with > about 3 bucks and change and brought it home. > > The pot will be to replace the RF GAIN control - which the PO had ditched in > favour of rigging up some sort of alternative RF Gain/AGC circuit. This is > the source of that extra knob on the front. This rework will, however, > continue tomorrow night. > > Tonight, my actual goals in working on the receiver were to undo the audio > mods, thereby unleashing the 6EH5 again. For some reason, the PO shorted the > grid to the cathode and ran a piece of RG-174 from this to the INJ jack. He > moved the INJ over to the SPARE location and installed another RCA jack > there. Why? Darned if I know. It seems he didn't need the high-level > audio, probably because he was using an external audio amp. I have no idea > why he'd want to move (and cut!) the INJ shielded line. Anyway, as luck > would have it, after removing that piece of RG-174, I determined that it was > the perfect length to go from the correct jack back over to T4. So, I > removed the old shielded cable from T4 to the SPARE jack and installed the > free end of the piece of RG-174 over to its correct location on T4. It's > very tight in there around the bandswitch! I removed what I thought was an > extra capacitor on the board nearest the AF GAIN control. > > When I turned the rig on, I was greeted with nothing! At least there was no > smoke... > > I found a couple of problems. That "extra" cap was moved over to the foil > side of the board to make room for a big electrolytic that's paralleled > across one of the terminals on the can cap (a bad idea that will be addressed > later - maybe) I had removed a .47 that was substituted for the original .01 > that couples the audio output to the speaker! No wonder there was no audio! > Put a new .01 on the foil side and voila! Now I can keep the AF GAIN barely > cracked open and get plenty of audio - just like it was designed to do! > > A more troubling matter reared its head - the INJ didn't seem to be working > properly. Strangely enough, if I switched to the transmitter, I was getting > signals as tuned by BOTH PTO's. Obviously, the negative bias wasn't working > for some reason. After metering and sniffing around, I found a wire attached > to the resistor board directly beneath the PTO that wasn't soldered! I'm > amazed this receiver had worked for as long as it did - this was the wire > from T4 to the resistor board. I re-soldered this wire and everything's > working as it should (except the RF Gain, of course). > > I'm done for this evening. I sliced open the tip of my left index finger > whilst trimming the RG-174 with my nice-n-sharp Swiss Army Knife. It's now > starting to hurt. > > Tomorrow, I begin the process of unraveling the RF GAIN and AGC mods. This > one's going to be a lot more work. Once those changes are done, I'll put two > - count 'em - headphone jacks in: one mono jack where it's supposed to be (on > the side) and one to plug the hole in the front panel, which I'll rig as a > L-R-shorted stereo jack so that one can use stereo phones without an adaptor. > I figure that if the damn hole is going to be there anyway, it might as well > do something useful! > > Pete, again, thanks for being the pioneer. With a stone-stock, working R-4B > that I can use - plus Garey's CD - I'm having an easier time than you > probably did. Getting to that 150-ohm resistor is going to be a challenge. > > Enjoy Those Drakes... > > Steve Wedge, W1ES/4 > > To be is to do - Socrates > To do is to be - Plato > Do be do be do. - Sinatra > > All my computers have my signature with various pearls of wisdom appended > thereto. > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > <http://mailman.zerobeat.net/pipermail/drakelist/attachments/20111102/d43d6e24/attachment-0001.html> > > ------------------------------ > > Message: 2 > Date: Wed, 2 Nov 2011 18:43:13 -0700 > From: "Pete Juliano" <[email protected]> > To: "Steve Wedge" <[email protected]>, "Drake List" > <[email protected]> > Subject: Re: [Drakelist] R-4B Mod removal, Part 1 > Message-ID: <F25D9DB6AB144377BFCB63820DFA94CC@UNIT0> > Content-Type: text/plain; charset="iso-8859-1" > > Hi Steve, > > Actually I did it all in two days so it was a little longer than one > afternoon. But that also included testing all of the tubes, cleaning the > chassis top and putting de-oxit on the switch terminals with the > micro-applicator and giving all the tube pins a shot of de-oxit and back into > their sockets. Finding the missing 2.2M Ohm resistor took the longest. If I > had Garey's CD that would have been much faster. I now have it so any more > work will go faster. BTW the 2.2M resistor was missing on the other radio I > know of besides yours. You didn't mention if you addressed that --but the AGC > won't work without that resistor. > > Look carefully and the 6BZ6 and you might find that 150 Ohm resistor has just > been moved slightly out of the way and not removed totally. That was the case > in two radios from that lot. If it is there then a clean up of the Cathode > pin with solder wick it will let you slide that puppy right in place and you > are there. If you want to plug the hole in the front panel then you can use a > 5/16 black plastic plug and it will fit nicely and the hole sort of > disappears into the front panel. I found one such plug at my local hardware > store. > > 73's > Pete N6QW > > > > > From: Steve Wedge > Sent: Wednesday, November 02, 2011 5:37 PM > To: Drake List > Subject: [Drakelist] R-4B Mod removal, Part 1 > > > I'm not as brave as Pete (N6QW) - if I assume that he restored his R-4B all > at once. Chances are, he didn't, but he did give me a darn good road-map. > My first goals for this evening were to check to see if Radio Shack really > did sell long-shafted 10k pots anymore - they do (!) and so I parted with > about 3 bucks and change and brought it home. > > The pot will be to replace the RF GAIN control - which the PO had ditched in > favour of rigging up some sort of alternative RF Gain/AGC circuit. This is > the source of that extra knob on the front. This rework will, however, > continue tomorrow night. > > Tonight, my actual goals in working on the receiver were to undo the audio > mods, thereby unleashing the 6EH5 again. For some reason, the PO shorted the > grid to the cathode and ran a piece of RG-174 from this to the INJ jack. He > moved the INJ over to the SPARE location and installed another RCA jack > there. Why? Darned if I know. It seems he didn't need the high-level > audio, probably because he was using an external audio amp. I have no idea > why he'd want to move (and cut!) the INJ shielded line. Anyway, as luck > would have it, after removing that piece of RG-174, I determined that it was > the perfect length to go from the correct jack back over to T4. So, I > removed the old shielded cable from T4 to the SPARE jack and installed the > free end of the piece of RG-174 over to its correct location on T4. It's > very tight in there around the bandswitch! I removed what I thought was an > extra capacitor on the board nearest the AF GAIN control. > > When I turned the rig on, I was greeted with nothing! At least there was no > smoke... > > I found a couple of problems. That "extra" cap was moved over to the foil > side of the board to make room for a big electrolytic that's paralleled > across one of the terminals on the can cap (a bad idea that will be addressed > later - maybe) I had removed a .47 that was substituted for the original .01 > that couples the audio output to the speaker! No wonder there was no audio! > Put a new .01 on the foil side and voila! Now I can keep the AF GAIN barely > cracked open and get plenty of audio - just like it was designed to do! > > A more troubling matter reared its head - the INJ didn't seem to be working > properly. Strangely enough, if I switched to the transmitter, I was getting > signals as tuned by BOTH PTO's. Obviously, the negative bias wasn't working > for some reason. After metering and sniffing around, I found a wire attached > to the resistor board directly beneath the PTO that wasn't soldered! I'm > amazed this receiver had worked for as long as it did - this was the wire > from T4 to the resistor board. I re-soldered this wire and everything's > working as it should (except the RF Gain, of course). > > I'm done for this evening. I sliced open the tip of my left index finger > whilst trimming the RG-174 with my nice-n-sharp Swiss Army Knife. It's now > starting to hurt. > > Tomorrow, I begin the process of unraveling the RF GAIN and AGC mods. This > one's going to be a lot more work. Once those changes are done, I'll put two > - count 'em - headphone jacks in: one mono jack where it's supposed to be (on > the side) and one to plug the hole in the front panel, which I'll rig as a > L-R-shorted stereo jack so that one can use stereo phones without an adaptor. > I figure that if the damn hole is going to be there anyway, it might as well > do something useful! > > Pete, again, thanks for being the pioneer. With a stone-stock, working R-4B > that I can use - plus Garey's CD - I'm having an easier time than you > probably did. Getting to that 150-ohm resistor is going to be a challenge. > > Enjoy Those Drakes... > > Steve Wedge, W1ES/4 > > To be is to do - Socrates > To do is to be - Plato > Do be do be do. - Sinatra > > All my computers have my signature with various pearls of wisdom appended > thereto. > > > > -------------------------------------------------------------------------------- > > > _______________________________________________ > Drakelist mailing list > [email protected] > http://mailman.zerobeat.net/mailman/listinfo/drakelist > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > <http://mailman.zerobeat.net/pipermail/drakelist/attachments/20111102/a115fd53/attachment-0001.html> > > ------------------------------ > > Message: 3 > Date: Thu, 3 Nov 2011 08:33:55 -0400 (GMT-04:00) > From: Steve Wedge <[email protected]> > To: Pete Juliano <[email protected]>, Drake List > <[email protected]> > Subject: Re: [Drakelist] R-4B Mod removal, Part 1 > Message-ID: > <29727547.1320323635757.javamail.r...@wamui-hunyo.atl.sa.earthlink.net> > > Content-Type: text/plain; charset="us-ascii" > > An HTML attachment was scrubbed... > URL: > <http://mailman.zerobeat.net/pipermail/drakelist/attachments/20111103/563ab175/attachment.html> > > ------------------------------ > > _______________________________________________ > Drakelist mailing list > [email protected] > http://mailman.zerobeat.net/mailman/listinfo/drakelist > > > End of Drakelist Digest, Vol 41, Issue 7 > **************************************** > -- Paul Gerhardt K3PG http://pgerhardt.blogspot.com QRP ARCI 6674 FP 274 "You must do this work with love or you fail." -- John Muir, from How to Keep Your Volkswagen Alive _______________________________________________ Drakelist mailing list [email protected] http://mailman.zerobeat.net/mailman/listinfo/drakelist
