Re: [Drakelist] L4B oddity
My question would now be (since you're assuming you'll have to drop a bunch of money on it anyway...) - what's the power out with it as it is, and how does it compare to how it was before you noticed the problem? Jim's right about the resistance: at 15A or thereabouts per filament @ 5V, milliohms make a difference! Steve, W1ES/4 -Original Message- >From: Jim Shorney >Sent: Jan 3, 2012 11:26 PM >To: "drakelist@zerobeat.net" >Subject: Re: [Drakelist] L4B oddity > > >Do you ever run with color on the plates? It's required that they get a little >bit red in operation for the gettering to work. > >Also, just a tiny bit of extra resistance in the filament pin is all it takes >to dim a tube. An ordinary Ohmmeter won't register the difference. > >73 > >-Jim > > >On Tue, 3 Jan 2012 22:00:06 -0600, richard radke wrote: > >>All, >> >>Thanks to everyone who made suggestions. Solder on the pins all look >>ok. .5½'s on each filament. I'm guessing a grid to filament short/ >>leak when it gets hot. I did notice a slight bit of clouding near >>the top of the envelope that wasn't there before. Maybe from running >>the filament with way less than 5V. Thoughts ? At any rate, a >>replacement 3-400Z is gonna be hard to find (out of production for >>years) so I'll probably just get a new 3-500 to go with the one I >>already have. >> >>Rick >>W9WS >> > > >-- >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://incolor.inetnebr.com/jshorney >http://www.nebraskaghosts.org > > > >___ >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] L4B oddity
To see if there are filament problems, I have found that attaching flea clips to the filament wires (not pins) and running leads outside the amp to a vtvm or vom is a way to see if there is a problem in the filament circuit. Since high voltage is involved, this is NOT something a novice should even attempt. It is ONLY for experts who are completely familiar with high voltage equipment and associated safety! -Original Message- From: David To: 'Jim Shorney' ; drakelist Sent: Tue, Jan 3, 2012 6:35 pm Subject: Re: [Drakelist] L4B oddity Agree. Using an ohm meter would show little unless zero. For example, if the resistance caused by the pin adds 0.1 ohm, then for a 15 amp filament, that is a 1.5 volt drop; 30% less than normal. If you had a grid to filament short you were right on time for the new year's fireworks. I have also read MANY YEARS AGO THAT THE REDISH COLOR IS A HEALTHY NORMAL, so unless there is a crack in the glass, running it hot when the filaments are fixed, should get it back to the right unclouded condition. Again, careful! Good luck. David Assaf, III W5XU -Original Message- From: drakelist-boun...@zerobeat.net [mailto:drakelist-boun...@zerobeat.net] On Behalf Of Jim Shorney Sent: Tuesday, January 03, 2012 10:26 PM To: drakelist@zerobeat.net Subject: Re: [Drakelist] L4B oddity Do you ever run with color on the plates? It's required that they get a little bit red in operation for the gettering to work. Also, just a tiny bit of extra resistance in the filament pin is all it takes to dim a tube. An ordinary Ohmmeter won't register the difference. 73 -Jim On Tue, 3 Jan 2012 22:00:06 -0600, richard radke wrote: >All, > >Thanks to everyone who made suggestions. Solder on the pins all look >ok. .5½'s on each filament. I'm guessing a grid to filament short/ >leak when it gets hot. I did notice a slight bit of clouding near the >top of the envelope that wasn't there before. Maybe from running the >filament with way less than 5V. Thoughts ? At any rate, a replacement >3-400Z is gonna be hard to find (out of production for >years) so I'll probably just get a new 3-500 to go with the one I >already have. > >Rick >W9WS > -- 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://incolor.inetnebr.com/jshorney http://www.nebraskaghosts.org ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.1901 / Virus Database: 2109/4721 - Release Date: 01/03/12 ___ 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] L4B oddity
Agree. Using an ohm meter would show little unless zero. For example, if the resistance caused by the pin adds 0.1 ohm, then for a 15 amp filament, that is a 1.5 volt drop; 30% less than normal. If you had a grid to filament short you were right on time for the new year's fireworks. I have also read MANY YEARS AGO THAT THE REDISH COLOR IS A HEALTHY NORMAL, so unless there is a crack in the glass, running it hot when the filaments are fixed, should get it back to the right unclouded condition. Again, careful! Good luck. David Assaf, III W5XU -Original Message- From: drakelist-boun...@zerobeat.net [mailto:drakelist-boun...@zerobeat.net] On Behalf Of Jim Shorney Sent: Tuesday, January 03, 2012 10:26 PM To: drakelist@zerobeat.net Subject: Re: [Drakelist] L4B oddity Do you ever run with color on the plates? It's required that they get a little bit red in operation for the gettering to work. Also, just a tiny bit of extra resistance in the filament pin is all it takes to dim a tube. An ordinary Ohmmeter won't register the difference. 73 -Jim On Tue, 3 Jan 2012 22:00:06 -0600, richard radke wrote: >All, > >Thanks to everyone who made suggestions. Solder on the pins all look >ok. .5½'s on each filament. I'm guessing a grid to filament short/ >leak when it gets hot. I did notice a slight bit of clouding near the >top of the envelope that wasn't there before. Maybe from running the >filament with way less than 5V. Thoughts ? At any rate, a replacement >3-400Z is gonna be hard to find (out of production for >years) so I'll probably just get a new 3-500 to go with the one I >already have. > >Rick >W9WS > -- 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://incolor.inetnebr.com/jshorney http://www.nebraskaghosts.org ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.1901 / Virus Database: 2109/4721 - Release Date: 01/03/12 ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L4B oddity
Do you ever run with color on the plates? It's required that they get a little bit red in operation for the gettering to work. Also, just a tiny bit of extra resistance in the filament pin is all it takes to dim a tube. An ordinary Ohmmeter won't register the difference. 73 -Jim On Tue, 3 Jan 2012 22:00:06 -0600, richard radke wrote: >All, > >Thanks to everyone who made suggestions. Solder on the pins all look >ok. .5½'s on each filament. I'm guessing a grid to filament short/ >leak when it gets hot. I did notice a slight bit of clouding near >the top of the envelope that wasn't there before. Maybe from running >the filament with way less than 5V. Thoughts ? At any rate, a >replacement 3-400Z is gonna be hard to find (out of production for >years) so I'll probably just get a new 3-500 to go with the one I >already have. > >Rick >W9WS > -- 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://incolor.inetnebr.com/jshorney http://www.nebraskaghosts.org ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L4B Oddity
I remember those little rolls well, as well as working on those old Tek room-heaters. The CRT's had the most wonderfully sharp traces, though - especially the 547 :) Steve, W1ES/4 -Original Message- >From: Garey Barrell >Sent: Jan 2, 2012 10:26 PM >To: Don Cunningham >Cc: richard radke , drakelist@zerobeat.net >Subject: Re: [Drakelist] L4B Oddity > >Don - > >There seems to be a lot of confusion over 'silver solder' and 'silver-bearing >solder'. > >Silver solder melts at around 1300 degree F, and is typically applied with a >small torch. It's >primarily used for jewelry and other tasks needing a 'hard' solder. I doubt >if the glass metal >seals around the filament pins of the 3-500Z would withstand that heat without >fracturing. I could >be wrong... > >Silver-bearing solder melts at around 700 degrees F, and is applied using our >more familiar >soldering irons. This solder is used for soldering parts that have >metalization 'flashed' onto >ceramic or other insulator, such as SMD parts and the famous Tektronix ceramic >tie strips used in >their scopes. Plain Lead/Tin 63/37% solder will 'leach' the silver out of the >flashed metalization, >loosening and finally breaking the bond. This is why Tek included small rolls >of silver-bearing >solder inside their products. > >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 > > >Don Cunningham wrote: >> On the first question, I have heard of the solder melting out of the pins on >> the filaments of both >> the 3-500Z and the 3-400's. If that has happened to your tube, you might be >> able to just >> re-solder it and be okay. Some have said to silver solder it, but it seems >> to me that silver >> solder requires an awful lot of heat and I would be careful doing that. >> >> Second question: I wouldn't think that was a good idea, but then I'm no >> expert, so hope Evan is >> out there, hi. >> 73, >> Don, WB5HAK >> >> > >___ >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] L4B Oddity
On Mon, 2 Jan 2012 22:07:05 -0600, Don Cunningham wrote: > I use 63/37 here nearly all the >time, only use the 60/40 outside on the antenna wires in a larger size and >was afraid the 63/37 would melt too easily. 63/37 melts at almost the same temp as 60/40, but it has the advantage of going from liquid to solid almost instantly as it cools below the melting point (eutectic), with no "plastic" range to increase the risk of poor connections. 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://incolor.inetnebr.com/jshorney http://www.nebraskaghosts.org ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L4B Oddity
Thanks for that clarification, Garey. I had never heard of "silver-bearing" solder. I've told you that I never was in electronics professionally, and only had the minimal USN training for radio ops, not the Electronics Techs that did get the full, "good stuff", hi. The silver solder I was referring to I used as a young lad in an electrician's shop and had something to do with an appliance I had to repair. Now, this was 1963 or 64, so forgive my loss of memory on what it was, hi. I remembered using a small torch on a small gas bottle of some sort and it got REALLY hot, much more than I would use on a tube pin. Your explanation tells me now that I was at least partially correct. That said, would you recommend silver-bearing solder in the 3-400/3-500's if we run across this problem in our amps?? I use 63/37 here nearly all the time, only use the 60/40 outside on the antenna wires in a larger size and was afraid the 63/37 would melt too easily. 73,and thanks as always, Don, WB5HAK ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L4B Oddity
On Mon, 02 Jan 2012 22:26:58 -0500, Garey Barrell wrote:
>There seems to be a lot of confusion over 'silver solder' and 'silver-bearing
>solder'.
Indeed, someone "edumacated" me on the semantics some time back. I've been
asked the question often enough that I still have the display card from the
solder I used right here on my desk. Alpha Fry 62946, Rosin core, 96% tin/4%
silver. Melting point 430F. I think I found it at Ace Hardware.
Tips on soldering 3-500Zs from the internet that I found handy were to place
the tube in an old sneaker to hold it steady while working, and pack wet paper
towel around the junction of the pins under attack and the glass envelope to
keep the seal from overheating. I removed as much of the old, crystallized
solder as I could with a spring-loaded solder sucker ("Soldapullit"). Then I
used lots of flux and fed in fresh solder, applying heat cautiously until I was
sure I had a good joint. Some folks unsolder all the pins and remove them from
the tube wires, but I just did the two filament pins. One of the recovered
tubes is still in service in my L-7, the other is on the shelf as a spare.
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://incolor.inetnebr.com/jshorney
http://www.nebraskaghosts.org
___
Drakelist mailing list
Drakelist@zerobeat.net
http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L4B Oddity
Don - There seems to be a lot of confusion over 'silver solder' and 'silver-bearing solder'. Silver solder melts at around 1300 degree F, and is typically applied with a small torch. It's primarily used for jewelry and other tasks needing a 'hard' solder. I doubt if the glass metal seals around the filament pins of the 3-500Z would withstand that heat without fracturing. I could be wrong... Silver-bearing solder melts at around 700 degrees F, and is applied using our more familiar soldering irons. This solder is used for soldering parts that have metalization 'flashed' onto ceramic or other insulator, such as SMD parts and the famous Tektronix ceramic tie strips used in their scopes. Plain Lead/Tin 63/37% solder will 'leach' the silver out of the flashed metalization, loosening and finally breaking the bond. This is why Tek included small rolls of silver-bearing solder inside their products. 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 Don Cunningham wrote: On the first question, I have heard of the solder melting out of the pins on the filaments of both the 3-500Z and the 3-400's. If that has happened to your tube, you might be able to just re-solder it and be okay. Some have said to silver solder it, but it seems to me that silver solder requires an awful lot of heat and I would be careful doing that. Second question: I wouldn't think that was a good idea, but then I'm no expert, so hope Evan is out there, hi. 73, Don, WB5HAK ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L4B Oddity
On Mon, 2 Jan 2012 19:41:59 -0600, David wrote: >Do a very close and careful check of the filament pins on the tube. The >tube sockets used were notorious for relaxing the friction connection on the >pins; the higher resistance created heat and the solder of the pins flowed >out. The fix is to resolder the pins Careful not to overheat I've fixed two tubes this way. Google finds plenty of documentation on this problem, and tips on how to solder safely and what kind of solder to use. Mostly on the Amps reflector, IIRC. There may be some info in the Drakelist archive, I think this has come up before. You want a high temperature solder alloy, generic tin/lead is not recommended. 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://incolor.inetnebr.com/jshorney http://www.nebraskaghosts.org ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L4B Oddity
Do a very close and careful check of the filament pins on the tube. The tube sockets used were notorious for relaxing the friction connection on the pins; the higher resistance created heat and the solder of the pins flowed out. The fix is to resolder the pins Careful not to overheat David Assaf, III W5XU -Original Message- From: drakelist-boun...@zerobeat.net [mailto:drakelist-boun...@zerobeat.net] On Behalf Of richard radke Sent: Monday, January 02, 2012 6:31 PM To: drakelist@zerobeat.net Subject: [Drakelist] L4B Oddity I have an unusual situation underway in my L4B. Evan, you out there? Been working fine until yesterday (i know, well happy new year) one of the 3-400's filaments is half as bright as the other. I reversed the tubes and the same tube was dimmer in the opposite "hole", and the amp and supply seems like they're running hotter than normal. HV is normal, but haven't keyed it yet or applied drive. Pwr supply was rebuilt a couple years ago with one of Mike's boards. Has anyone seen a tube fail like this? Being a week after xmas and the YL's birthday Friday, not real anxious to spend 5 big ones on a pair of 3-500's right now, but a guys gotta do what a guys gotta do. 2nd question. I've got one 3-500 spare that I believe to be good. Has anyone ever mixed a 3-400 and a 3-500 in the same amp? Only for testing purposes. Just asking. Rick W9WS ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.1901 / Virus Database: 2109/4719 - Release Date: 01/02/12 ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L4B Oddity
On the first question, I have heard of the solder melting out of the pins on the filaments of both the 3-500Z and the 3-400's. If that has happened to your tube, you might be able to just re-solder it and be okay. Some have said to silver solder it, but it seems to me that silver solder requires an awful lot of heat and I would be careful doing that. Second question: I wouldn't think that was a good idea, but then I'm no expert, so hope Evan is out there, hi. 73, Don, WB5HAK ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
