AW12 1 dial speaker question - EH Scott Radio Enthusiasts2024-03-28T11:05:48Zhttps://ehscott.ning.com/forum/topics/aw12-1-dial-speaker-question?commentId=3925821%3AComment%3A65181&feed=yes&xn_auth=noI tried the SW bands and they…tag:ehscott.ning.com,2018-03-18:3925821:Comment:652952018-03-18T18:27:19.392ZAuroraoldradioshttps://ehscott.ning.com/profile/Auroraoldradios
<p>I tried the SW bands and they seem to be ok. The SW tuner parts are in the cabinet and work as expected. I'm not sure when I'll start on the tuner chassis. I re-capped the amp chassis a few weeks ago. Here's a pic of Mike's bezel- looks great. Thanks, Mike.<a href="http://storage.ning.com/topology/rest/1.0/file/get/2771124013?profile=original" target="_self"><img width="640" class="align-full" src="http://storage.ning.com/topology/rest/1.0/file/get/2771124013?profile=original"/></a></p>
<p>I tried the SW bands and they seem to be ok. The SW tuner parts are in the cabinet and work as expected. I'm not sure when I'll start on the tuner chassis. I re-capped the amp chassis a few weeks ago. Here's a pic of Mike's bezel- looks great. Thanks, Mike.<a href="http://storage.ning.com/topology/rest/1.0/file/get/2771124013?profile=original" target="_self"><img width="640" class="align-full" src="http://storage.ning.com/topology/rest/1.0/file/get/2771124013?profile=original"/></a></p> Aha,
Good news, now comes the…tag:ehscott.ning.com,2018-03-16:3925821:Comment:652942018-03-16T11:17:58.999Zmike hadleyhttps://ehscott.ning.com/profile/mikehadley
<p>Aha,</p>
<p>Good news, now comes the fun of recapping, are you going to replace or stuff the caps.</p>
<p>have you tried any of the short wave bands yet?</p>
<p>Mike</p>
<p></p>
<p>Aha,</p>
<p>Good news, now comes the fun of recapping, are you going to replace or stuff the caps.</p>
<p>have you tried any of the short wave bands yet?</p>
<p>Mike</p>
<p></p> After tracing some wiring I f…tag:ehscott.ning.com,2018-03-16:3925821:Comment:652462018-03-16T02:10:43.222ZAuroraoldradioshttps://ehscott.ning.com/profile/Auroraoldradios
<p>After tracing some wiring I found the jumper at the sensitivity switch to the IF cathodes was broken off. I re-soldered it. The rest of the wiring appeared to be ok. It looks like no one has been in there since it left the factory. A quick power up on my Sencore Powerite showed good current consumption. AM Broadcast reception is quite good. Even the dial is very close to the correct frequency markings.</p>
<p>After tracing some wiring I found the jumper at the sensitivity switch to the IF cathodes was broken off. I re-soldered it. The rest of the wiring appeared to be ok. It looks like no one has been in there since it left the factory. A quick power up on my Sencore Powerite showed good current consumption. AM Broadcast reception is quite good. Even the dial is very close to the correct frequency markings.</p> Dan;
Your assumption is proba…tag:ehscott.ning.com,2018-03-06:3925821:Comment:651052018-03-06T23:31:27.933Zmike hadleyhttps://ehscott.ning.com/profile/mikehadley
<p>Dan;</p>
<p>Your assumption is probably correct, as the external audio drives the cathode and the grid circuit is connected then you must have a signal on the anode, as you do.</p>
<p>One possibility is that the wunderlich has gone low emission,</p>
<p>check your local oscillator is running, try injecting a signal to the preceding if grids, working away from the wunderlich.</p>
<p>I built a simple signal injector years ago, really crude but can find a fault in seconds.</p>
<p>Mike</p>
<p>Dan;</p>
<p>Your assumption is probably correct, as the external audio drives the cathode and the grid circuit is connected then you must have a signal on the anode, as you do.</p>
<p>One possibility is that the wunderlich has gone low emission,</p>
<p>check your local oscillator is running, try injecting a signal to the preceding if grids, working away from the wunderlich.</p>
<p>I built a simple signal injector years ago, really crude but can find a fault in seconds.</p>
<p>Mike</p> I was checking the schematics…tag:ehscott.ning.com,2018-03-06:3925821:Comment:651042018-03-06T23:11:41.779ZAuroraoldradioshttps://ehscott.ning.com/profile/Auroraoldradios
<p>I was checking the schematics and see that the phono input goes on the Wunderlich cathode. The 55 tube (I had a 2A6) trick didn't help. I need to check voltages on sockets and see what I have. With the Wunderlich in place, the phono input works fine. I also see some meter movement when the Wunderlich is inserted suggesting the tube is ok. I have a couple of tube testers I could use but I don't have settings for it. </p>
<p>I was checking the schematics and see that the phono input goes on the Wunderlich cathode. The 55 tube (I had a 2A6) trick didn't help. I need to check voltages on sockets and see what I have. With the Wunderlich in place, the phono input works fine. I also see some meter movement when the Wunderlich is inserted suggesting the tube is ok. I have a couple of tube testers I could use but I don't have settings for it. </p> Thanks Norman. I have to figh…tag:ehscott.ning.com,2018-03-05:3925821:Comment:652122018-03-05T20:45:14.137ZDavid C. Polandhttps://ehscott.ning.com/profile/DavidCPoland
<p>Thanks Norman. I have to fight to remember it ends with an "H" not a "K"</p>
<p>The Wunderlich tube is ahead of the audio phono input circuit. So the Wunderlich tube is not a factor in using the phono input. You do need a working Wunderlich tube for radio reception.</p>
<p>A temporary substitute is a 55 tube as follows. Short length of insulated solid wire, stripped at both ends. Use fine sand paper or steel wool to clean the #4 pin of the 55 tube and the grid cap of the 55 tube. Tightly…</p>
<p>Thanks Norman. I have to fight to remember it ends with an "H" not a "K"</p>
<p>The Wunderlich tube is ahead of the audio phono input circuit. So the Wunderlich tube is not a factor in using the phono input. You do need a working Wunderlich tube for radio reception.</p>
<p>A temporary substitute is a 55 tube as follows. Short length of insulated solid wire, stripped at both ends. Use fine sand paper or steel wool to clean the #4 pin of the 55 tube and the grid cap of the 55 tube. Tightly double wrap one end of the wire to the 55 tube pin 4 (one of the two diodes in the 55 tube). Tack solder the other wire end to the grid cap of the 55 tube. Insert the 55 tube in the Wunderlich tube socket. Not optimal, but you should get some radio reception and at least allow you to continue with trouble shooting and alignment of the IF stages.</p>
<p>Although there is also a Scott factory recommended conversion to use a 55 tube involving a circuit change and drilling a hole for a grid cap wire, I believe performance suffers. One of my AW-15's has this change. Wunderlich tubes had became unavailable, hence this factory alteration. But Wunderlich tubes do how up these days and I recommend using one in you set.</p>
<p></p>
<p></p>
<p> </p> I re-soldered all of the lead…tag:ehscott.ning.com,2018-03-05:3925821:Comment:652112018-03-05T19:20:57.679ZAuroraoldradioshttps://ehscott.ning.com/profile/Auroraoldradios
<p>I re-soldered all of the leads and it works ok. Audio comes thru the phono jack amplified loud and clear. Still no tuner action. Time to break out the signal generator.</p>
<p>I re-soldered all of the leads and it works ok. Audio comes thru the phono jack amplified loud and clear. Still no tuner action. Time to break out the signal generator.</p> If you want to search eBay fo…tag:ehscott.ning.com,2018-03-05:3925821:Comment:651032018-03-05T19:09:47.904ZNorman S Braithwaitehttps://ehscott.ning.com/profile/NormanSBraithwaite
<p>If you want to search eBay for the tube, spell it Wunderlich.</p>
<p>Norman</p>
<p>If you want to search eBay for the tube, spell it Wunderlich.</p>
<p>Norman</p> I have also have a bad Wunder…tag:ehscott.ning.com,2018-03-05:3925821:Comment:652102018-03-05T16:36:36.489ZDavid C. Polandhttps://ehscott.ning.com/profile/DavidCPoland
<p>I have also have a bad Wunderlick as a display tube. Tested fine but in less than a minute of operation it winks out.</p>
<p>Make sure the tube pins make good contact in the socket. Expansion as the tube heats likely triggers the problem. Next, reheat the two filament pins and try to introduce some additional solder into the pins for a possible fix. Also, the globe tubes don't support the innards like the later shouldered tube envelope would. Look carefully at the tube to see if the innards…</p>
<p>I have also have a bad Wunderlick as a display tube. Tested fine but in less than a minute of operation it winks out.</p>
<p>Make sure the tube pins make good contact in the socket. Expansion as the tube heats likely triggers the problem. Next, reheat the two filament pins and try to introduce some additional solder into the pins for a possible fix. Also, the globe tubes don't support the innards like the later shouldered tube envelope would. Look carefully at the tube to see if the innards lean to the side - a sign the tube was dropped. If so, slam the tube against your hand a couple times to try to straighten the innards to perhaps fix the problem - has worked for me on a couple other globe tubes and nothing really lost if slamming finishes off the intermittent tube. Slamming to straighten the innards once fixed a dud globe 27 tube.</p>
<p>I can supply a good used tested Arcturus Wundelick that I have test run in my AW-12. dcp944@ yahoo.com. They also appear on eBay with unknown condition, as few sellers have tube testers with settings for a Wunderlick (but I have an early 1930's Supreme that does). You need the 2.5 volt version, not the 6 volt.</p>
<p>The unusual Wunderlick tube was the first modern tube designed specifically for detection. Has two inter wound (co-cylindrical) grids around the cathode sharing the same plane. Designed to be a full wave push-pull detector and also amplify the detected audio signal and, at the same time, provide potentials for automatic volume control from the center tap of the final I F transformer secondary. Scott's use is an example off using fringe technology for leading edge performance - seen in the later AW-12 production you have and early production of the AW-15.</p> Yes, I checked everything on…tag:ehscott.ning.com,2018-03-05:3925821:Comment:650492018-03-05T14:55:41.270ZAuroraoldradioshttps://ehscott.ning.com/profile/Auroraoldradios
<p>Yes, I checked everything on the speaker itself and all was well. I finished it and it sounds great using the RCA jack to feed a CD signal. Now I need to see why the Wunderlich filament won't stay lit. Someone glued the base so it make me wonder if it has an intermittent open. The socket contacts test ok.</p>
<p>Yes, I checked everything on the speaker itself and all was well. I finished it and it sounds great using the RCA jack to feed a CD signal. Now I need to see why the Wunderlich filament won't stay lit. Someone glued the base so it make me wonder if it has an intermittent open. The socket contacts test ok.</p>