[Drakelist] R-7 Digital Control Board Update
Greetings: I still haven't fixed my R-7 yet but I'm making progress. I bought a digital control board from a TR-7 & tried it & found that all but the lowest 3 bands worked; the board outputs for the 3 bands that didn't work were all continually low, incidentally, while the outputs from the PROM that fried were all floating. Next I connected 8 SPDT toggle switches so that each would select either ground or +5V & connected them to the DR-7 board in place of the digital control board & used them to make a truth table documenting the successful patterns for each band. Not surprisingly, the patterns from the control board match those of the DR-7 output lines to the translator board. If anyone would like a copy of this truth table send me an e-mail off list. My next step is to build something that'll respond to the band switch inputs with the required outputs, now that I know what they need to be. I've designed a circuit that'll do this using a 4-input AND gate for each band [11 in total; actually 6-4082s] plus inverters & [Schottky] steering diodes although possibly there are simpler ways to do this. I'll make a schematic for this circuit available once it's done & working properly in case there's any interest. 73s. Dave ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
drakelist@zerobeat.net
There is a very thin piece of double sided tape on the far right side of the front panel. That and the meter hold the panel on. 73, Joe KC9LAD At 10:18 PM 1/31/2010, you wrote: Ok, The Antenna selector switch on my MN-2700 suddenly went weird - I could not select anything - it seemed like none of the detents would engage. I opened the unit up and after some poking around realized that the detent part of the switch which is in the front is only tied to the inner front panel by the nut on the shaft. How do I tighten the nut? After a lot more head scratching I have found that the meter seems to hold the left side of the front panel but the right side won't free up - is there a screw in there that I have to find from the back? What a puzzle this box is - I guess Drake never figured these controls would loosen up. Ouch! Many thanks Steve KD2ED ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] TR-7 PBT 10K Pots
Thanks to all who replied, have the info that I needed. Better research on my part would have found this, but nice to have the resource. 73, Robb NØRU Woodland Park, CO. ___ 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] What circa tube tester?
Yep, just about one "step" on the filament select switch! :-) 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 4-B, C-Line& TR-4/C Service Supplement CDs Robert Ladden wrote: That got me wondering how much the life test drops the filament voltage. I put a 6JB6A in my tester and measured the filament voltage. The tester's "normal" 6.3V was really 6.2V. The life test dropped it to 5.6V. On a 12AX7 it dropped from 12.7V to 11.6V. So it only drops the voltage about 9%. 73, Bob WW3QB --- On Sun, 1/31/10, Garey Barrell wrote: From: Garey Barrell Subject: Re: [Drakelist] What circa tube tester? To: Drakelist@zerobeat.net Date: Sunday, January 31, 2010, 11:41 AM Bob - That's a very good site reference. Lots of good information there. The "Life Test" typically just reduces the filament voltage on the tube. This indicates whether the cathode is straining to deliver enough electrons, (wearing out,) or has "life" left! If the meter indications stays steady or only drops slightly, then the tube has considerable life left, at least from an emission standpoint. If the meter drops a lot, not good. You can perform a similar test on any tube tester, merely switch the filament voltage DOWN one step, i.e., from 6.3 to 5 volts. A "good" tube will drop only a few divisions, while a "weak" one will drop 5 to 10 or more divisions. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 4-B, C-Line& TR-4/C Service Supplement CDs ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
drakelist@zerobeat.net
Ok, The Antenna selector switch on my MN-2700 suddenly went weird - I could not select anything - it seemed like none of the detents would engage. I opened the unit up and after some poking around realized that the detent part of the switch which is in the front is only tied to the inner front panel by the nut on the shaft. How do I tighten the nut? After a lot more head scratching I have found that the meter seems to hold the left side of the front panel but the right side won't free up - is there a screw in there that I have to find from the back? What a puzzle this box is - I guess Drake never figured these controls would loosen up. Ouch! Many thanks Steve KD2ED ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] FS SP 75 Speech Processor for "7" line
SP 75 is in great condition and is working. I used it on my TR 7 and got very good audio reports. Extra punch helps sometimes. I am selling my 7 line so this SP 75 is surplus to my needs. Priced at 110.00 shipped Paypal preferred. I have pics if you like to see the unit. Dennis ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] What circa tube tester?
That got me wondering how much the life test drops the filament voltage. I put a 6JB6A in my tester and measured the filament voltage. The tester's "normal" 6.3V was really 6.2V. The life test dropped it to 5.6V. On a 12AX7 it dropped from 12.7V to 11.6V. So it only drops the voltage about 9%. 73, Bob WW3QB --- On Sun, 1/31/10, Garey Barrell wrote: > From: Garey Barrell > Subject: Re: [Drakelist] What circa tube tester? > To: Drakelist@zerobeat.net > Date: Sunday, January 31, 2010, 11:41 AM > Bob - > > That's a very good site reference. Lots of good > information there. > > The "Life Test" typically just reduces the filament voltage > on the tube. This indicates whether the cathode is > straining to deliver enough electrons, (wearing out,) or has > "life" left! If the meter indications stays steady or > only drops slightly, then the tube has considerable life > left, at least from an emission standpoint. If the > meter drops a lot, not good. > > You can perform a similar test on any tube tester, merely > switch the filament voltage DOWN one step, i.e., from 6.3 to > 5 volts. A "good" tube will drop only a few divisions, > while a "weak" one will drop 5 to 10 or more divisions. > > 73, Garey - K4OAH > Glen Allen, VA > > Drake 2-B, 4-B, C-Line& TR-4/C Service Supplement > CDs > ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] PS 7 regulator card.
I need a regulator card from a PS 7. Anyone out there have one available? Thanks Gary (WB7DIE)___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] TR-7 PBT 10K Pots
You need one Bourns 1k pot 3296W-1-102LF for the 10 volt adjustment, and 5 Bourns 10k pots 3296W-1-103LF for the passband frequency adjustments. They are $2.19 each at Newark. You also have to move the resistors in between the original pots to the backside of the board. Here is a link to a website that has very good pictures of this. http://members.ziggo.nl/cmulder/drake.htm#bookmark5 73, Joe Pyles KC9LAD At 06:54 PM 1/31/2010, you wrote: Good Afternoon, My TR-7's PBT pots have finally reached the point of failing to maintain the correct frequency for both U/Lsb. I am going to replace all 5 pots when I pull the board and was wondering if anyone has had much luck finding higher quality replacements? I am considering 15-20 turn types if they will fit into the same space as the originals. I'd rather not have to modify the board too much, but would like to hear from anyone who might have tried this. I've looked at Mouser and found some that are close, but figured I'd try this resource first. Thanks. Robb NØRU Woodland Park, CO. ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] TR-7 PBT 10K Pots
Good Afternoon, My TR-7's PBT pots have finally reached the point of failing to maintain the correct frequency for both U/Lsb. I am going to replace all 5 pots when I pull the board and was wondering if anyone has had much luck finding higher quality replacements? I am considering 15-20 turn types if they will fit into the same space as the originals. I'd rather not have to modify the board too much, but would like to hear from anyone who might have tried this. I've looked at Mouser and found some that are close, but figured I'd try this resource first. Thanks. Robb NØRU Woodland Park, CO. ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] What circa tube tester?
I'll second the Jackson 648. I have an older and a later model 648A. Did not know about Vacuum Tube inc doc. It looks like I may have most of the factory data (manuals, test charts, updates) but for the price I think I'll get a copy. Thanks Bob!!! It's not perfect, but is great for finding known bad apples. 73, Ron WD8SBB --- On Sun, 1/31/10, Robert Ladden wrote: > From: Robert Ladden > Subject: Re: [Drakelist] What circa tube tester? > To: Drakelist@zerobeat.net, "Richard Palmer" > Date: Sunday, January 31, 2010, 11:18 AM > I have had good luck with a Jackson > 648A tester. It is not an expensive Hickok mutual > conductance tester. It uses a "Dynamic" testing circuit and > there is much debate if that is really better than simple > emission testing. But it does have a test I have found > useful. It has a “Life Line Indicator” test which > reduces the filament voltage. It sounds like a gimmick but > it seems to work for me. Just last month I had a weak 12AX7 > in my T-4XC. It tested good in the regular test, but > it was bad in the life test. I replaced the tube and now I > don’t have to turn the gain so high to tune up. That test > has also worked for me with other tubes. > > That life test has also been useful for 6JB6’s. It has > found soft tubes with the life test that otherwise have > tested good. Whether it finds all soft tubes is a question, > but it has proven to be a good screener by finding tubes for > me that have tested to be soft in my T-4XC (I had a box of > unknown tubes). But swapping tubes is by far the best > test but at least I can eliminate the "no chance" ones. > > My Jackson 648A did not come with the 9-pin NOVAR socket > needed for 6JB6’s. I added it myself and it was not hard > to do using the schematic. One advantage for the Jackson 648 > is that Vacuum Tubes Inc. publishes their own manual for it > (I have no connection to this company except as a customer). > > > There is an excellent discussion of tube testers at > http://www.tone-lizard.com/Tube_Testers.html > It is written from an audiophile’s point of view, the > only other group still using tubes. > > 73, > Bob WW3QB > > > --- On Sat, 1/30/10, Richard Palmer > wrote: > > > From: Richard Palmer > > Subject: [Drakelist] What circa tube tester? > > To: Drakelist@zerobeat.net > > Date: Saturday, January 30, 2010, 9:03 PM > > I hope this is not off topic. > > With the use of "vintage" being used for all Drakes > and tube > > testers, many from the 1940's and before, up to the > last > > ones made, it has become impossible for me to > determine what > > will service my early TR-4. > > > > I have spent hours and hours looking up tube testers > by > > type, make and model. I have spent hours squinting at > > pictures trying to count socket pins. I am burnt out > and am > > looking for help in finding just where to look. I have > no > > idea if post WWII testers even test 9 pins, or if all > 7 pins > > are of the same size. > > > > Richard Palmer > > KB8NXO > > > > -- The law, in its majestic equality, forbids the rich > as > > well as the poor to sleep under bridges, to beg in > the > > streets, and to steal bread. - Anatole > > France > > > > > > ___ > > 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
Re: [Drakelist] T4X-C Won't maintain output
Hmm. Several oddities with this. 1. Usually lower transmitter output is experienced when RCVR control is selected, bringing the PreMixer signal over from the receiver. 2. If it was a cable problem, 80M is the least likely to have increased losses as it is the lowest frequency PreMixer signal. 3. Why would transmitter alignment "fix" it, but only for a short while.? Most obvious is a problem with the TRANSCEIVE switch contacts. Have they been cleaned, DeoxIT'ed? If we were talking 10M, I'd suspect the trimmer cap adjustment changing since typically they are very near minimum capacitance and so have very low tension on the adjuster screws. But ... On 80M, what alignment adjustments would be "drifting" with time? Possibly a leaky mica cap on the PreMixer on the 80M band position. C142, C145, C156 or C185. Only other thought would be marginal levels from the PTO, Band Osc or PreMixer, falling off with time. Possibly a gassy V8? Be sure and let us know what you find! 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 4-B, C-Line& TR-4/C Service Supplement CDs Chuck Pool wrote: Hi to all: After aligning the T4X-C the power output is equal when switching between R4-C or T4X-C control via the transcieve switch on the transmitter. Now, the output is lower when the transcieve switch is in the T4X-C position. This is for 80 meters. I aligned the transmitter again and output is same/normal when switching between receive or transmitter control via the transcieve swithch on the T4X-C. Again, later, the output falls when selecting the transmitter control via the transceive swithch on the T4X-C. I may tune up the transmitter again. However, I am gettig tired of doing this. Any ideas what is going on? 73, Chuck ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] What circa tube tester?
-I have a Hickock that my bookeeper gave me 35 years ago (her husband "liberated" it from the phone co,) Great unit...still works good 73 Bud WØHG ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] What circa tube tester?
Bob - That's a very good site reference. Lots of good information there. The "Life Test" typically just reduces the filament voltage on the tube. This indicates whether the cathode is straining to deliver enough electrons, (wearing out,) or has "life" left! If the meter indications stays steady or only drops slightly, then the tube has considerable life left, at least from an emission standpoint. If the meter drops a lot, not good. You can perform a similar test on any tube tester, merely switch the filament voltage DOWN one step, i.e., from 6.3 to 5 volts. A "good" tube will drop only a few divisions, while a "weak" one will drop 5 to 10 or more divisions. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 4-B, C-Line& TR-4/C Service Supplement CDs Robert Ladden wrote: I have had good luck with a Jackson 648A tester. It is not an expensive Hickok mutual conductance tester. It uses a "Dynamic" testing circuit and there is much debate if that is really better than simple emission testing. But it does have a test I have found useful. It has a “Life Line Indicator” test which reduces the filament voltage. It sounds like a gimmick but it seems to work for me. Just last month I had a weak 12AX7 in my T-4XC. It tested good in the regular test, but it was bad in the life test. I replaced the tube and now I don’t have to turn the gain so high to tune up. That test has also worked for me with other tubes. That life test has also been useful for 6JB6’s. It has found soft tubes with the life test that otherwise have tested good. Whether it finds all soft tubes is a question, but it has proven to be a good screener by finding tubes for me that have tested to be soft in my T-4XC (I had a box of unknown tubes). But swapping tubes is by far the best test but at least I can eliminate the "no chance" ones. My Jackson 648A did not come with the 9-pin NOVAR socket needed for 6JB6’s. I added it myself and it was not hard to do using the schematic. One advantage for the Jackson 648 is that Vacuum Tubes Inc. publishes their own manual for it (I have no connection to this company except as a customer). There is an excellent discussion of tube testers at http://www.tone-lizard.com/Tube_Testers.html It is written from an audiophile’s point of view, the only other group still using tubes. 73, Bob WW3QB ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] What circa tube tester?
On Sun, 31 Jan 2010 08:18:24 -0800 (PST), Robert Ladden wrote: >I have had good luck with a Jackson 648A tester. It is not an expensive Hickok >mutual conductance tester. It uses a "Dynamic" testing circuit and there is >much debate if that is really better than simple emission testing. But it does >have a test I have found useful. I use a Jackson 658A. It is a late model, with the adapter that has sockets for most of the tube types used in the 60s and 70s. It supports most of the tube types, although I did have to fudge up a test for the 8950 recently. Not hard to do if there is a roughly equivalent type you can use as a reference. The life test is useful, as you say. Garey's comments on tube testers are accurate and well thought out. One thing that a good tester WILL do for you is help sort out shorted or gassy tubes, which could potentially cause damage when plugged in to a radio. They will also, of course, tell you if a tube is just dead, and can somtimes help find an intermittent tube (but you can also do that in the radio). 73 -Jim -- Ham Radio NU0C Lincoln, Nebraska, U.S.S.A. TR7/RV7/R7A/L7, TR6/RV6, T4XC/R4C/L4B, NCL2000, SB104A, R390A, GT550A/RV550A, HyGain 3750, IBM PS/2 - all vintage, all the time! "Give a man a URL, and he will learn for an hour; teach him to Google, and he will learn for a lifetime." HyGain 3750 User's Group - http://groups.yahoo.com/group/HyGain_3750/ http://radiojim(dot)exofire(dot)net http://incolor.inetnebr.com/jshorney http://www.nebraskaghosts.org ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] TR7 acting strange
On Sun, 31 Jan 2010 11:13:53 -0500, Garey Barrell wrote: >I would add one thing to Gary's suggestion below. You have had the DR-7 >board in and out a time or two, and those long pins have a problem of >cracking the solder joints. Excellent advice. I will add to that, the female contacts can also become deformed from repeated removal/reinsertion, and make intermittent contact. They can be inspected visually, and the fix is to desolder the connector from the board, remove the contact from the shell, and re-form it. A little DeOxit down't hurt either (but don't SPRAY!). >One other strange problem I've seen is on some units, >if you push the DR-7 board down too far, the pins can actually touch the >Parent board, intermittently, of course :-) I've seen pins stick far enough through the female connector to contact bare component legs next to the connector. That will drive you nuts. A great trick I found for the DR7 is to add a couple of the small stick-on rubber feet (the flat ones, not the rounded variety) along the bottom of the rear edge of the board. This lets the board seat down just the right amount in that area, which seems to be the easiest area to push down too far. 73 -Jim -- Ham Radio NU0C Lincoln, Nebraska, U.S.S.A. TR7/RV7/R7A/L7, TR6/RV6, T4XC/R4C/L4B, NCL2000, SB104A, R390A, GT550A/RV550A, HyGain 3750, IBM PS/2 - all vintage, all the time! "Give a man a URL, and he will learn for an hour; teach him to Google, and he will learn for a lifetime." HyGain 3750 User's Group - http://groups.yahoo.com/group/HyGain_3750/ http://radiojim(dot)exofire(dot)net http://incolor.inetnebr.com/jshorney http://www.nebraskaghosts.org ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] TR7
On Sun, 31 Jan 2010 10:35:49 -0500, Curt Nixon wrote: >Good Morning All: > >Regarding my TR7: > >It has AC on the carrier in CW mode. >that could do this. Filters on the PS board in the TR perhaps? Could be, but I would say replace them anyway. I always say that. They are getting old and will eventually start to fail. That is one of the things on my "must do" list WRT refurbing a TR7. >A second issue is that I notice the pilot lights dimming when keying and >an associated slight chirp in the sidetone..although there is no >detectable chirp on the RF signal. I'm not really concerned about the >lights but I read the article about adding the low current feed lines to >the DC cable and it said something about copupling the voltage variation >into the audio circuits. WIll the low current isolation alter the >chirpy sidetone? Probably not, although it is a recommended mod anyway. For sidetone issues, see K8AC's excellent article on fixing CW issues here: http://www.wb4hfn.com/DRAKE/DrakeArticles/TR7_Key_Clicks.pdf 73, -Jim -- Ham Radio NU0C Lincoln, Nebraska, U.S.S.A. TR7/RV7/R7A/L7, TR6/RV6, T4XC/R4C/L4B, NCL2000, SB104A, R390A, GT550A/RV550A, HyGain 3750, IBM PS/2 - all vintage, all the time! "Give a man a URL, and he will learn for an hour; teach him to Google, and he will learn for a lifetime." HyGain 3750 User's Group - http://groups.yahoo.com/group/HyGain_3750/ http://radiojim(dot)exofire(dot)net http://incolor.inetnebr.com/jshorney http://www.nebraskaghosts.org ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] TR7 acting strange
On Sun, 31 Jan 2010 03:46:11 -0800 (PST), Ron wrote: >Thanks to all who replied. At this time, the rig is working for unknown >reasons. I guess it is going to be a PITA intermittent. Don't feel too bad, I had an intermittent with my DR7 board that took me several years of "now-and-then" troubleshooting and resoldering to finally track down. Don't give up, the radio is worth the trouble. 73 -Jim -- Ham Radio NU0C Lincoln, Nebraska, U.S.S.A. TR7/RV7/R7A/L7, TR6/RV6, T4XC/R4C/L4B, NCL2000, SB104A, R390A, GT550A/RV550A, HyGain 3750, IBM PS/2 - all vintage, all the time! "Give a man a URL, and he will learn for an hour; teach him to Google, and he will learn for a lifetime." HyGain 3750 User's Group - http://groups.yahoo.com/group/HyGain_3750/ http://radiojim(dot)exofire(dot)net http://incolor.inetnebr.com/jshorney http://www.nebraskaghosts.org ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] What circa tube tester?
I have had good luck with a Jackson 648A tester. It is not an expensive Hickok mutual conductance tester. It uses a "Dynamic" testing circuit and there is much debate if that is really better than simple emission testing. But it does have a test I have found useful. It has a “Life Line Indicator” test which reduces the filament voltage. It sounds like a gimmick but it seems to work for me. Just last month I had a weak 12AX7 in my T-4XC. It tested good in the regular test, but it was bad in the life test. I replaced the tube and now I don’t have to turn the gain so high to tune up. That test has also worked for me with other tubes. That life test has also been useful for 6JB6’s. It has found soft tubes with the life test that otherwise have tested good. Whether it finds all soft tubes is a question, but it has proven to be a good screener by finding tubes for me that have tested to be soft in my T-4XC (I had a box of unknown tubes). But swapping tubes is by far the best test but at least I can eliminate the "no chance" ones. My Jackson 648A did not come with the 9-pin NOVAR socket needed for 6JB6’s. I added it myself and it was not hard to do using the schematic. One advantage for the Jackson 648 is that Vacuum Tubes Inc. publishes their own manual for it (I have no connection to this company except as a customer). There is an excellent discussion of tube testers at http://www.tone-lizard.com/Tube_Testers.html It is written from an audiophile’s point of view, the only other group still using tubes. 73, Bob WW3QB --- On Sat, 1/30/10, Richard Palmer wrote: > From: Richard Palmer > Subject: [Drakelist] What circa tube tester? > To: Drakelist@zerobeat.net > Date: Saturday, January 30, 2010, 9:03 PM > I hope this is not off topic. > With the use of "vintage" being used for all Drakes and tube > testers, many from the 1940's and before, up to the last > ones made, it has become impossible for me to determine what > will service my early TR-4. > > I have spent hours and hours looking up tube testers by > type, make and model. I have spent hours squinting at > pictures trying to count socket pins. I am burnt out and am > looking for help in finding just where to look. I have no > idea if post WWII testers even test 9 pins, or if all 7 pins > are of the same size. > > Richard Palmer > KB8NXO > > -- The law, in its majestic equality, forbids the rich as > well as the poor to sleep under bridges, to beg in the > streets, and to steal bread. - Anatole > France > > > ___ > 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] What circa tube tester?
Richard - This might be due to relay K2 contacts. This is the relay that shifts the Carrier Oscillator to within the LSB filter passband for CW operation. Be worthwhile to clean those contacts with a little DeoxIT soaked paper strip. ** This may be one of those, "shoulda' sent it in private" messages :-) ** 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 4-B, C-Line& TR-4/C Service Supplement CDs Richard Palmer wrote: Thanks to all for the advice and expertise. Anyone who has looked at tube testers know that "the" one to get is high dollar. You would think that for the amount the design gets that it would also repair a bad or questionable tube. :-) Dollar for dollar I might be ahead on this just to buy a new set of tube types for my TR-4 and go from there. I feel relatively curtain I have a hinky tube because after the set warms up there is often a change in audio that goes from a low pitch to high pitch or vise a versa sound on my back ground noise. If I change over to X-CW and back the audio returns to normal. Maybe a good cleaning will help. I'll find out. Thanks again, Richard Palmer ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] TR7 acting strange
I would add one thing to Gary's suggestion below. You have had the DR-7 board in and out a time or two, and those long pins have a problem of cracking the solder joints. The two sets of pins on the left side, the ones where the "bypass" board plug in, are what takes the codes from the Translator to VCO that he's referring to. I would reflow the solder on all those pins. One other strange problem I've seen is on some units, if you push the DR-7 board down too far, the pins can actually touch the Parent board, intermittently, of course :-) I try to keep responses on the list, unless it just gets too far in the weeds. I think some are concerned they'll be attacked if they give a "wrong" answer. This list is pretty good about that sort of thing. I've been wrong a time or two, maybe, ... ?? :-) On the other hand, you may just have to wait for it to DIE !! :-) 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 4-B, C-Line& TR-4/C Service Supplement CDs Ron wrote: Thanks to all who replied. At this time, the rig is working for unknown reasons. I guess it is going to be a PITA intermittent. I so often see a problem on the list and then see thanks but never the answer as to what fixed the issue. For those looking in the archives for answers, it is a disappointment. I too went "off list" with some e-mail, info is reposting below. Ron WD8SBB: ...Although the rig is playing now, it twice showed issues similar to that described below (check 5, 7, + 21Mhz freq).I have tried to poke apart T2101 with a plastic stick, but it appears fine === Gary, W8PU: Ron, It looks as if the wrong bcd code is going to the translater board causing either the VCO to hunt ( out of range ) or for the wrong frequency to be generated for a given bandswitch position. Try reseating the DR-7 board. 73, Gary Garey K4oah: Interesting. I've never heard of a solid state power supply needing a "warm-up"! :-) I would be suspicious of C2109 or C2108 also, although usually leaky caps go the other way, i.e., leakage goes UP as they warm up. The diodes in the bridge are switching diodes, but should work ok. I'd look at C2108 and C2109 at turn-on to see if they ramp up. I've never looked, and it's possible that this is NORMAL, since it comes up fairly quickly. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 4-B, C-Line& TR-4/C Service Supplement CDs --- On Sat, 1/30/10, Ron wrote: From: Ron Subject: Re: [Drakelist] TR7 acting strange To: k4...@mindspring.com Cc: Drakelist@zerobeat.net Date: Saturday, January 30, 2010, 12:16 PM Garey, Even thought I had spontaneous healing of my TR7 per our e-mail discussion, I opened up the rig and did some voltage tests. Rig in SSB, all boards installed. Pin spec measured 1 -5V -3.43 2 +25 23.3 3 gnd 4 AM 4.99 5 RTTY7.01 6 CW 4.31 7 LSB 6.26 8 USB 3.83 9 DCin13.53 10 +10VDC 10.01 11 +5V 4.90 The 24VDC line stayed solid as I moved the bandswitch and up down buttons. Per the drake service dept alignment procedures, pin 2 should measure between 23.25-24.0. Assuming my meter is accurate, that voltage is very close to being out of spec low. Maybe a weak/leaky C2110? I could not get to the input of U2103 (24V regulator) without pulling the DR7 board. Pulled it and installed probes and then reinstalled the DR7. Input to the 78c24 was at 27VDC immediately after turning on the rig, and then climbed to 32-35 volts w/i about 10 seconds. As I recall the 7800 family of chips need 2 volts to regulate, so I think input is w/i spec even at turn on. When switching the bandswitch, it made the input voltage move, but never under the 32 volt level. Caveat, using a DVM so it may have "spikes" that I was not seeing. After this, I pulled the DR7 and replaced it with the service kit "jumper logic board". Basically had the same results with it in place of the DR7 board. TNX es 73, Ron --- On Mon, 1/25/10, Garey Barrell wrote: From: Garey Barrell Subject: Re: [Drakelist] TR7 acting strange To: "Ron" Date: Monday, January 25, 2010, 9:56 AM Ron - Definitely sounds like marginal VCO locking. The bands from 160 - 20M will all wander around 17 MHz. 15 and 10M bands will wander around 34 MHz. An "open" AUX-7 position will result in an unlocked VCO, as will pushing the FIXED RCV button in. First step is to check that +24V DC supply bus. That is the most likely cause of this, i.e., "random, occasional, loss of lock" on both PTOs. Certainly there are other possible causes, but that little transformer core is a problem, and the "super glue" that Drake used to put it together is letting go (after only 40 years or so). Easy fix, just glue it back on. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 4-B, C-Line& TR-4/C Service Supplement CD
[Drakelist] T4X-C Won't maintain output
Hi to all: After aligning the T4X-C the power output is equal when switching between R4-C or T4X-C control via the transcieve switch on the transmitter. Now, the output is lower when the transcieve switch is in the T4X-C position. This is for 80 meters. I aligned the transmitter again and output is same/normal when switching between receive or transmitter control via the transcieve swithch on the T4X-C. Again, later, the output falls when selecting the transmitter control via the transceive swithch on the T4X-C. I may tune up the transmitter again. However, I am gettig tired of doing this. Any ideas what is going on? 73, Chuck ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] TR7
Good Morning All: Regarding my TR7: It has AC on the carrier in CW mode. It looks to have original caps in the PS7 and I just havent gotten around to replacing them. I have also noted taht the rx signal has a "scratchineess" on it ..especially when using the narrower filters. It isn't audio hum..in fact there is no evidence of any hum in the audio--but it is identical to the signal I here from the TX when monitored on another rig. So yesterday, i temporarily added 10,000mFd cap to the system in the PS7 thinking it might get me by until I can order the big caps. It made zero detectable difference. Now I'm wondering if there is anything else that could do this. Filters on the PS board in the TR perhaps? A second issue is that I notice the pilot lights dimming when keying and an associated slight chirp in the sidetone..although there is no detectable chirp on the RF signal. I'm not really concerned about the lights but I read the article about adding the low current feed lines to the DC cable and it said something about copupling the voltage variation into the audio circuits. WIll the low current isolation alter the chirpy sidetone? Thanks Curt KU8L ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] What circa tube tester?
Richard - That is an excellent book. All those terms are just fancy names for what we call GAIN. Simply put, it refers to what happens if we put filament, plate, (screen) and grid potentials on a tube, and then "wiggle" the voltage on the grid, what happens to the current through the tube. Go easy with the DeoxIT, don't spray it around, and preferably put the liquid ON switch contacts and no where else. As for the relay, take a narrow strip of good paper, wet it with DeoxIT, and then put it between a pair of closed relay contacts and draw it out. Hold the relay closed with your finger to do the Normally Open sets. Drake was not always consistent with the Voltage and Resistance charts! There were eight (8) versions of the TR-4, and often they would just change the schematic, but not always the photos and V & R charts. So if I use them at all, I use them as guides only. If a reading is way out of what the chart says it should be, check the schematic for YOUR unit. I have seen instances where the cathode of a tube is connected directly to the chassis, and the resistance chart shows 470 ohms. A check of schematics shows that once upon a time, there WAS a cathode resistor in this stage, but not any more in this version! Aside from that, ALL TR-4(any) versions had 20 tubes.! VR20 is the 0A2, kinda "out of order" on the schematics. Nah, I don't know of anyone who can determine a bad tube just by looking... :-) Unless the glass is broken or there are metal parts rattling around inside! Generally speaking, if a tube gets hot when turned on, it's working. It may not be great, but it's probably working. Aside from an open filament, the main failures in tubes (unless broken glass or metal pieces are loose!) are the cathode coating has had all the electrons wrung out of it, or the glass seals (where pins go through the glass) have leaked allowing air inside. Generally speaking, Drake designed their circuits to work over a wide range of tube characteristics, and good quality tubes were originally manufactured with characteristics very close to specifications. So the equipment will continue to work, often within specifications, over a wide range of tube degradation. One exception, of course, is the 6JB6 PA tubes. They are being pushed to their limit, and DO degrade with use. IF you ALWAYS keep the plate current dipped, with only a second or two of "off resonance" operation, these tubes will last for years. My "daily driver" B-Line has tubes that are over ten years old, and they still have full output. I can change bands in less than 5-10 seconds with "muscle memory"! :-) What kills finals are the guys that key the transmitter, then look for their glasses so they can see the meter AND find the manual, and THEN dip the PLATE. The very characteristic of these tubes that made them desirable in the first place, i.e., LARGE plate current with low voltages, is what kills them IF operated off resonance. One tube can draw as much as 1 AMP of current off resonance, and since if the plate circuit is not at resonance, all that POWER has to be dissipated by the plate, which very quickly becomes red, then yellow, then white hot, just before the glass melts enough to suck a hole in it! Very quickly, defined as _seconds_. So don't sweat it so much. If all the tubes get hot when turned on, they're probably good enough to "work". The only tube I've seen that was DEAD operationally but still hot, was a few 6JB6s that probably had all their cathode material evaporated, melted or blown off.! 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 4-B, C-Line& TR-4/C Service Supplement CDs Richard Palmer wrote: Gary, I don't think I'm the only one that's gonna hang onto this for future reference! One of the things I have read is "Getting The Most Out Of Vacuum Tubes" by Robert B. Tomer. So I have a reference for what you are saying regarding testing in circuit, re-tubing ect. I know that if you read one thing on Emission testing, you have read everything about it. I have spent considerable time covering transconductance, mutual conductance, Dynamic conductance and maybe others. I am going to start cleaning my TR-4 after the "eagle flies" this week. This is a new to me radio and it needs to be cleaned and aligned. After I clean it with deoxit I want to check the tubes. (I should probably be more concerned with cleaning the relay but that will happen on it's own.) I can't afford to buy a set of tubes to try and see what will happen with tube substitution after cleaning it. This sorta leads to something else that I don't understand. The resistance chart for the tubes goes from V-1 - V20. The schematic shows tubes V-19A and V-19b but not a V-20. Just something I noticed in preparing to do this. I'm sure there are those here who can look at a tube and win a bet as to weather or not it is good. They might want to over look my posts. I b
[Drakelist] TR4 Manual
I have a TR4 original manual. Condition is around 5 to 6, staples are out, schematic good. How about $10. this includes the cost of Priority Mail and for me to get a cup of coffee and dognut at Tim Hortons. 73' jim/w8ngo __ Information from ESET Smart Security, version of virus signature database 4822 (20100131) __ The message was checked by ESET Smart Security. http://www.eset.com ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] Orlando FL Hamcation Info
Orlando FL Hamcation Information: The Orlando Hamcation is less than two weeks away. It will be held from February 12 thru February 14, but much of the activity starts on Thursday, February 11, when most of the tailgaters set up. If you have not made your plans to attend, you need to do so now. Florida is the place to be in February! Info can be found at http://hamcation.com/default.html There is a lot of information at this web site, so be certain to check all of the special areas. At the present time, there are a few tables still available in the swap building. All of the wall spaces and end caps have been taken. If you want more than one table together, get your reservation in NOW. Having a table inside the building, instead of outside in the tailgate area, protects you (and your equipment) from the weather, and only costs $10 more for the entire weekend. Please e-mail hamcat...@aol.com to make reservations or get more information. Everyone knows that there are many other activities in the central Florida area, so be certain to bring the XYL. Hamcation will also have YL activities, and of course many are now hams, so will enjoy Hamcation as well. The bottom line is "Bring the entire family." Advance registrations are running considerably ahead of last year, so this promises to be another large (10,000 plus hams) hamfest. To put it another way, don't stay home because you think attendance might be down due to the economy. It does not look that way. See you there! Thanks. 73, Ken, W8EK Ken Simpson E-mail to w...@flham.net or w...@arrl.net Voice Phone (352) 732-8400 ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] What circa tube tester?
Thanks to all for the advice and expertise. Anyone who has looked at tube testers know that "the" one to get is high dollar. You would think that for the amount the design gets that it would also repair a bad or questionable tube. :-) Dollar for dollar I might be ahead on this just to buy a new set of tube types for my TR-4 and go from there. I feel relatively curtain I have a hinky tube because after the set warms up there is often a change in audio that goes from a low pitch to high pitch or vise a versa sound on my back ground noise. If I change over to X-CW and back the audio returns to normal. Maybe a good cleaning will help. I'll find out. Thanks again, Richard Palmer Garey Barrell wrote: Richard - First, there are two major types of tube testers. The least expensive is the "Emission" type which merely applies power to the filament and plate of a tube and measures the current on a "Good-?-Bad" meter scale. They are slightly better than using an ohmmeter on the filament pins to see if the filament is intact! The more expensive type, the "Mutual Conductance" type, applies filament and plate voltage and then applies a known AC signal to the grid to measure the actual "gain" of the tube. The Emission tester will tell you if the cathode is still emitting electrons, and the Mutual Conductance tester will tell you how the tube amplifies _at the single test point and level_ chosen by the tester manufacturer. Neither tells you much of anything about operation at RF. Typically only the "latest" tube testers will test the "Compactron" type of tubes (6JB6) without some sort of adapter. One of the better tube testers available is the military TV-7/U family. It doesn't have sockets to test the Compactrons, but someone has made a set of adapters for it to allow it to test the common sweep tubes, like the 6JB6. All the rest of the tubes in the Drake gear are 7 and 9 pin "miniature" types, which just about any tester made after about 1940 will test. These tubes are all the same size pins and pin circle. All that said, a tube tester isn't all that much help anyway. The only REAL test for a tube is in the circuit you want it to work in. Your best approach to maintaining your Drake gear is to get a couple of each tube type, "test" them by plugging into a working radio and if they work, put them in a safe place! This is especially true for 6JB6 tubes used at RF frequencies. These tubes were designed for use as horizontal output tubes for TV sets. They operated at almost 16 kHz in that service!! Sylvania, in the early 60's, characterized (tested) some of their "TV Sweep" tubes such as the 6JB6 for linear amplifier service from 2-30 MHz. The resulting data was used by Drake and several other Amateur equipment makers to develop transmitters that would run considerably more power than those using the 6146, and do it at a lower plate voltage! Add that the sweep tubes were about 1/3 to 1/2 the cost of the 6146, and that a lower plate voltage could be used for higher power output and it was a done deal. The pertinent characteristic was a high "perveance", or high currents at lower plate voltages. They were designed to operate 24/7, inside a TV set with 25 other tubes and keep working, so they were able to serve in CW or SSB service at considerably higher power levels than their published specifications.. The catch here is that since the tube was designed to operate at 16 kHz, NOT 30 MHz, not all brands of the same tube type were interchangeable. Operation at 30 MHz requires considerably more attention to internal tube structure such as lead lengths, interelement capacitance, etc. The result was that one manufacturer might make a 6JB6 with considerably higher reactances that worked just fine at 16 kHz, but would make it impossible to neutralize in an HF transmitter without changes in the neutralization circuitry. Add the fact the some of the smaller, even well known companies that put their name on a tube may well have had that tube made by more than one manufacturer, and it gets difficult to say which tubes will work in a T-4X and those that won't. Further complicating the situation is that the RF gain of a tube falls off with decreasing emission, and falls off first at the higher frequencies. 6JB6 tubes in T-4X service will fall off first on 10M, then 15, then 20, then ... Most will continue to put out SOME power on 80 and 40M after 10M output is just about zero. My experience has shown that Sylvania, Zenith, RCA and GE are the ONLY brands of 6JB6 that I have found to work _consistently_. Raytheon, Westinghouse, Standard, and most others are potential trouble. Some work, some don't, depending upon who _really_ made them. By the way, it is NOT a good idea to replace ALL the tubes in a radio at once. "Retubing" is somehow seen as similar to "replacing all your tires". This is not only wasteful of a finite sourc
Re: [Drakelist] TR7 acting strange
Thanks to all who replied. At this time, the rig is working for unknown reasons. I guess it is going to be a PITA intermittent. I so often see a problem on the list and then see thanks but never the answer as to what fixed the issue. For those looking in the archives for answers, it is a disappointment. I too went "off list" with some e-mail, info is reposting below. Ron WD8SBB: ...Although the rig is playing now, it twice showed issues similar to that described below (check 5, 7, + 21Mhz freq).I have tried to poke apart T2101 with a plastic stick, but it appears fine === Gary, W8PU: Ron, It looks as if the wrong bcd code is going to the translater board causing either the VCO to hunt ( out of range ) or for the wrong frequency to be generated for a given bandswitch position. Try reseating the DR-7 board. 73, Gary Garey K4oah: Interesting. I've never heard of a solid state power supply needing a "warm-up"! :-) I would be suspicious of C2109 or C2108 also, although usually leaky caps go the other way, i.e., leakage goes UP as they warm up. The diodes in the bridge are switching diodes, but should work ok. I'd look at C2108 and C2109 at turn-on to see if they ramp up. I've never looked, and it's possible that this is NORMAL, since it comes up fairly quickly. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 4-B, C-Line& TR-4/C Service Supplement CDs --- On Sat, 1/30/10, Ron wrote: > From: Ron > Subject: Re: [Drakelist] TR7 acting strange > To: k4...@mindspring.com > Cc: Drakelist@zerobeat.net > Date: Saturday, January 30, 2010, 12:16 PM > Garey, > Even thought I had spontaneous healing of my TR7 per our > e-mail discussion, I opened up the rig and did some voltage > tests. Rig in SSB, all boards installed. > > Pin spec measured > 1 -5V -3.43 > 2 +25 23.3 > 3 gnd > 4 AM 4.99 > 5 RTTY7.01 > 6 CW 4.31 > 7 LSB 6.26 > 8 USB 3.83 > 9 DCin13.53 > 10 +10VDC 10.01 > 11 +5V 4.90 > > The 24VDC line stayed solid as I moved the bandswitch and > up down buttons. > > Per the drake service dept alignment procedures, pin 2 > should measure between 23.25-24.0. Assuming my meter > is accurate, that voltage is very close to being out of spec > low. Maybe a weak/leaky C2110? > > I could not get to the input of U2103 (24V regulator) > without pulling the DR7 board. Pulled it and installed > probes and then reinstalled the DR7. Input to the > 78c24 was at 27VDC immediately after turning on the rig, and > then climbed to 32-35 volts w/i about 10 seconds. As I > recall the 7800 family of chips need 2 volts to regulate, so > I think input is w/i spec even at turn on. When > switching the bandswitch, it made the input voltage move, > but never under the 32 volt level. Caveat, using a DVM > so it may have "spikes" that I was not seeing. > > After this, I pulled the DR7 and replaced it with the > service kit "jumper logic board". Basically had the > same results with it in place of the DR7 board. > > TNX es 73, > Ron > > --- On Mon, 1/25/10, Garey Barrell > wrote: > > > From: Garey Barrell > > Subject: Re: [Drakelist] TR7 acting strange > > To: "Ron" > > Date: Monday, January 25, 2010, 9:56 AM > > Ron - > > > > Definitely sounds like marginal VCO locking. > > > > The bands from 160 - 20M will all wander around 17 > > MHz. 15 and 10M > > bands will wander around 34 MHz. > > > > An "open" AUX-7 position will result in an unlocked > VCO, as > > will pushing > > the FIXED RCV button in. > > > > First step is to check that +24V DC supply bus. > That > > is the most likely > > cause of this, i.e., "random, occasional, loss of > lock" on > > both PTOs. > > Certainly there are other possible causes, but that > little > > transformer > > core is a problem, and the "super glue" that Drake > used to > > put it > > together is letting go (after only 40 years or so). > > Easy fix, just glue > > it back on. > > > > 73, Garey - K4OAH > > Glen Allen, VA > > > > Drake 2-B, 4-B, C-Line& TR-4/C Service > Supplement > > CDs > > > > > > > > Ron wrote: > > > Garey, > > > I started to look at the TR7 last night. First > > was to see for sure what was going on frequency > wise. > > Turned it on, 80 meters, where I had left it and it > was > > fine. 2.5 then 1.5 wondering 17xxx.x 1.5. Back > > to 80 meters fine, and of course everything else was > fine > > too. So then I went back down to 2.5 and 1.5, they > too > > were fine now. So I thought maybe temperature or > time. > > Could not get it to fail after several hours. > > > > > > Got to playing and went to aux settings. They > > were fine with the band light lighting if I was not in > the > > correct band. Then I went to an open aux location > and > > got wondering 17xxx.x. I can not remember it that > has > > always been that way or not. Looks like it could be > > correct given the "block"
Re: [Drakelist] T4X-C. Now more output power and no RFI?
It sounds like something has changed in the antenna system or feed line. Bry, AF4K > Hi to all > My T4X-C always put out about 110 -120 watts, less on 20 - 10 > meters. On 40 meters there was > always RFI problems with our organ. > > Today, the T4X-C was putting out 150 watts on 80 meters. All the > other bands had much more > output power too. Amp meter said 400 - 450 mills. 320 - 350 mills is > normal for me.400 - 450 > amp mills seems to high? Is it? > > Now there is no RFI problem on 40 meters. > > What is going on? Any ideas? > > 73, > Chuck - AA5WG > Cedar, Michigan > > > ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
