Re: [Drakelist] Drake 2-B S-Meter Calibration/AVC
Dennis, Garey and everyone Happy 2009 to you all. Ihave been absent for few days. Indeed it was a gassy 6BA6 indeed which made all the trouble. For some reason during the quick swap I have not detected it was faulty the firts time. A lot of learning in this 2-B restoration ! Thanks for all the inputs. Fred - PY2XB On Fri, 26 Dec 2008 16:41:07 -0200, Dennis Monticelli dennis.montice...@gmail.com wrote: The minor changes to S-meter reading (transient or otherwise) as you introduce or remove AVC path components (Fast vs Slow and BFO) don't seem very revealing to me. The slow drift in the S-meter over several minutes is the revealing symptom. This latter behavior could be caused by a gassy tube whose grid is being fed from that very high impedance AVC line as Garey has suggested or by the grid having become contaminated and thus acting as a virtual cathode. So swapping out all those gain-control tubes with a fresh tube one at a time would be a good experiment. Dennis AE6C On Fri, Dec 26, 2008 at 3:26 AM, py...@integral.com.br wrote: Garey and Dennis, thanks agian for the inputs. Regarding tubes, I have replaced those afected by AVC/1 and AVC/2. Nothing changed. Maybe I will need to try to redo this based on what Garey wrote. I will get special attention to the 6BA6 which is driven by AVC/1. These are some effects that I would like to line up and make sure you have the details - After 10-15 minutes Smeter goes to S1. If I turn the radio off and on it will do again, but journey is shorter. The S-meter will come from S4 to S1 in 5-6 minutes. - During the journey to S1, after start up, if I am in Fast AVC and switch to Slow (introducing the 1uf capacitor), the S meter's needle deeps to the left and gets up again. I hear the RX background noise to pulse too. It does that once. - In any circusntance there is a slight S meter difference when I switch from SAVC to FastAVC and vice-versa. In SAVC it reads about half S unit more (to the right). - I have realized that when th BFO is on, the S-Meter moves a bit do the left. Normally I would answer to someone that would have posted something similar to it that the AVC discharge path is malfunctioning. I have checked the resistors in this path. I have also checked the time constant capacitor in the AV/2 and AV/1 circuits. I will have time to check spurios oscillation and/or grid leak whan I get back home. I will be away until year's eve or so. Please send any ideas that are very much welcome. Best regards Fred On Fri, 26 Dec 2008 04:19:24 -0200, Garey Barrell k4...@mindspring.com wrote: Fred - I have been traveling and missed some of this thread. Try subbing tubes in the AVC stages. Often an IF tube will be gassy, and the grid will lose control after 5-20 minutes of warmup. The 12BA6 is particularly susceptible to this problem, even in New Old Stock tubes. You sometimes have to try three or four before finding a good one. The AVC circuit is so hi-z that it takes very little grid current to upset it. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 4-B, C-Line TR-4/C Service Supplement CDs www.k4oah.com py...@integral.com.br wrote: Dennis, merry xmas to you and yours, firts of all. Thanks for the input. I don not know if I my explanation was clear enough. The long S-meter journey to S1 just occurs after power the unit up and for 10 or so minutes. After that the behaivor is normal. Yes my first shot was a opened path to discharge the AVC circuitry. Unfortunately I have not found anything to blame. Did you consider that after the initial pb the behaivor seems to be normal ? Regards Fred ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] r4a volume
well my r4a is turning out nicely but i am not sure about 10m. i have to turn the volume up to almost 2 o clock to here any noise. is the r4a deaf on 10? or do i maybe have a audio problem? the serial is 2952. i noticed some circuit difference when comparing it to another parts r4a i have. this one also has one more tube the other dose not. i am guessing this is a early model. does anyone have the same situation? Carey Lockhart, KC5GTT kc5...@gmail.com www.kc5gtt.com ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] r4a volume
Hi CArey: If it only on 10M, it is unlikey to be an audio issue. More likely an issue related to one of the bandswitched stages. Have you tried peaking the inj and rf amp trimmers for 10? 10 is pretty quiet these days here but regulart QRN should show up just like it does on 20 or 15 when they are closed down. I use R-4a ser # 6131--with the transistor VFO. Original owner. Curt KU8L Carey Lockhart wrote: well my r4a is turning out nicely but i am not sure about 10m. i have to turn the volume up to almost 2 o clock to here any noise. is the r4a deaf on 10? or do i maybe have a audio problem? the serial is 2952. i noticed some circuit difference when comparing it to another parts r4a i have. this one also has one more tube the other dose not. i am guessing this is a early model. does anyone have the same situation? Carey Lockhart, KC5GTT kc5...@gmail.com mailto:kc5...@gmail.com www.kc5gtt.com ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] r4a volume
hi Curt i did try peaking the different stages. when i tune to the calibrator signal i am only getting about 2 s units. as i go down the bands it move up in signal strength. i guess its just me. i haven't been playing with drakes very long so i really do not know how they are supposed to act. now i did find that c176 has a crack in it. maybe thats it. Carey Lockhart, KC5GTT kc5...@gmail.com www.kc5gtt.com On Jan 4, 2009, at 5:30 PM, Curt Nixon wrote: Hi CArey: If it only on 10M, it is unlikey to be an audio issue. More likely an issue related to one of the bandswitched stages. Have you tried peaking the inj and rf amp trimmers for 10? 10 is pretty quiet these days here but regulart QRN should show up just like it does on 20 or 15 when they are closed down. I use R-4a ser # 6131--with the transistor VFO. Original owner. Curt KU8L Carey Lockhart wrote: well my r4a is turning out nicely but i am not sure about 10m. i have to turn the volume up to almost 2 o clock to here any noise. is the r4a deaf on 10? or do i maybe have a audio problem? the serial is 2952. i noticed some circuit difference when comparing it to another parts r4a i have. this one also has one more tube the other dose not. i am guessing this is a early model. does anyone have the same situation? Carey Lockhart, KC5GTT kc5...@gmail.com mailto:kc5...@gmail.com www.kc5gtt.com - --- ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] r4a volume
On my schematic, C176 is the audio feedback electrolytic in the audio output section. Doubt if that would cause a 10M only issue. Itis normal for the cal signal to be weaker in the higher freq bands. The harmonics from the 100kHz osc get progressively weaker. If you use another drake t4x, leave the r4 in on and listen to yourself. you should have to turn the rf gain down to 1/4 but should be nice and clear. It should also hear the spot mode well. ALL of the electrolytics should be suspect if they are originals. The ones in the PS and audio sections will cause hum and general unpleasantness. Curt KU8L Carey Lockhart wrote: hi Curt i did try peaking the different stages. when i tune to the calibrator signal i am only getting about 2 s units. as i go down the bands it move up in signal strength. i guess its just me. i haven't been playing with drakes very long so i really do not know how they are supposed to act. now i did find that c176 has a crack in it. maybe thats it. Carey Lockhart, KC5GTT kc5...@gmail.com mailto:kc5...@gmail.com www.kc5gtt.com On Jan 4, 2009, at 5:30 PM, Curt Nixon wrote: Hi CArey: If it only on 10M, it is unlikey to be an audio issue. More likely an issue related to one of the bandswitched stages. Have you tried peaking the inj and rf amp trimmers for 10? 10 is pretty quiet these days here but regulart QRN should show up just like it does on 20 or 15 when they are closed down. I use R-4a ser # 6131--with the transistor VFO. Original owner. Curt KU8L Carey Lockhart wrote: well my r4a is turning out nicely but i am not sure about 10m. i have to turn the volume up to almost 2 o clock to here any noise. is the r4a deaf on 10? or do i maybe have a audio problem? the serial is 2952. i noticed some circuit difference when comparing it to another parts r4a i have. this one also has one more tube the other dose not. i am guessing this is a early model. does anyone have the same situation? Carey Lockhart, KC5GTT kc5...@gmail.com mailto:kc5...@gmail.com www.kc5gtt.com ___ Drakelist mailing list Drakelist@zerobeat.net mailto:Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] C-Line for sale
I have the following C-Line station for sale: R-4C, S/N 26886 with the 4nb noise blanker and the 1.5 khz and 500 hz filters installed T-4XC, S/N 29284 MS-4 speaker and AC-4 power supply This is a very clean set of Drake Twins and I am using them on the air now. Power output is good on all bands. The interconnecting cables, dust covers, and the manuals are included. Price is $800.00 plus shipping. I will only ship to the CONUS. If you are interested you may contact me at _w8...@aol.com_ (mailto:w8...@aol.com) . Thanks and 73, Terry, W8NJR **New year...new news. Be the first to know what is making headlines. (http://www.aol.com/?ncid=emlcntaolcom0026) ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] Accy's for 2-C?
Looking for 2-NB and/or 2-AC for my 2-C resto project. Any of these around? Or a junker 2-C for parts? Tx es 73, Darrell W4CX ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] R4C function switch, feet
The detents on the function switch on my R4C have worn out. At least they do not stop the switch at the functions. (except for the first one) I have reviewed the archives on the subject. Before attempting the silver solder repair, does anyone have a function switch they would part with. I also would like to purchase the rubber pads for the feet. Who was it that had those? Thanks Rick W0RT ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
