Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Williamblake on June 01, 2020, 03:54:49 pm
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I hate slaying old test gear just like the other guy but was wondering if you could reuse these Tektronix terminals without fancy silver solder? I think Mr Carlson mentioned in one of his videos the connections would eventualy break if not soft enough. But i couldn't find it again when i searched it. Does anybody know about this?
Regards,
Jens
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encase it^in^ acrylic and display as art :icon_biggrin:
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Just noticed they made a movie about it.
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Been using Tektronix my whole career, their equipment, service n doc's are the standard
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I ... was wondering if you could reuse these Tektronix terminals without fancy silver solder? ...
I personally wouldn't use them without using silver solder. Yes, silver solder is ~2-3 times the price of 60/40, but you can get more than you probably need for $30-60.
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This type of terminal has a silver alloy that's sintered to the ceramic. The use of 60/40 tin lead solder is said to break down the alloy-ceramic. I remember reading about this when I had an old Tek dual beam 556.
Tektronix does say you can use regular leaded solder sparingly, but they recommend "silver bearing" solder, which I think was developed for this.
**edit: actually, I just saw that video posted above. I was going to post some info in "Tektronix Manual: 181", but that clip pretty much tells you what ever you're gonna want to know. :)
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This type of terminal has a silver alloy that's sintered to the ceramic. The use of 60/40 tin lead solder is said to break down the alloy-ceramic. I remember reading about this when I had an old Tek dual beam 556.
Tektronix does say you can use regular leaded solder sparingly, but they recommend "silver bearing" solder, which I think was developed for this.
**edit: actually, I just saw that video posted above. I was going to post some info in "Tektronix Manual: 181", but that clip pretty much tells you what ever you're gonna want to know. :)
the conductor fired onto the alumina is palladium silver alloy. we used to make the bases for 3 phase hybrid bridges and 1 phase hybrid bridges using that method of conductor on ceramic (alumina). silver solder works best and minimizes leeching of the palladium silver. you CAN use tin/lead alloy, but leeching of the palladium silver eutectic becomes more of an issue, so rework (reflow) more that 2-3 times will destroy the bond. another conductor alloy that fires well on alumina is molybdenum manganese (molly-mag). it doesn't share the leeching issue that palladium silver does, but it is not as good of a conductor - IRRC, molly-mag has to fired at higher temp than palladium silver. y'all are rattling memories 30 years past. lol!
--pete
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the conductor fired onto the alumina is palladium silver alloy. we used to make the bases for 3 phase hybrid bridges and 1 phase hybrid bridges using that method of conductor on ceramic (alumina). silver solder works best and minimizes leeching of the palladium silver. you CAN use tin/lead alloy, but leeching of the palladium silver eutectic becomes more of an issue, so rework (reflow) more that 2-3 times will destroy the bond. another conductor alloy that fires well on alumina is molybdenum manganese (molly-mag). it doesn't share the leeching issue that palladium silver does, but it is not as good of a conductor - IRRC, molly-mag has to fired at higher temp than palladium silver. y'all are rattling memories 30 years past. lol!
--pete
Pete, you took the words right out of my mouth ;)
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Your choice. Is it worth the effort to try to salvage used terminal lugs? NOS, ok.
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OK, you fooled me. When I saw "Tektronix terminals", I thought of the Tektronix storage-tube graphics terminals the we used back in the 80's.
https://en.wikipedia.org/wiki/Tektronix_4010
That said, there is another thing related to soldering and ceramic in my history, but that's another story. (Didn't go down that path, so no experience.)
Ed
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A cli digital effect maybe? And just for the record i never killed Tektronix gear, just happen to have these terminals. Thanks for sharing all the experiences, i will have to look up most of the words and save the terminals till i happen to run into silver solder. Is there a way to tell its silver solder without a label i wonder. Oh, just read about the cadmium.
https://www.vintage-radio.net/forum/showthread.php?t=139544
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Note that "silver bearing" is NOT the same as Silver Solder.
http://www.johnsonmfg.com/2015/tincoppersilver.htm
https://www.amazon.com/RadioShack-SnPbAg-Silver-Bearing-Rosin-Core-Diameter/dp/B07NK59QRY
https://www.amazon.com/Electrical-Silver-Bearing-Rosin-Solder/dp/B07XF87RP7
https://www.homedepot.com/p/SOLDER-IT-Silver-Bearing-Solder-Paste-SP-7/300916097
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Of course i hadn't noticed that, yet. Thanks. Also found this:
http://w140.com/tekwiki/wiki/Ceramic_Strips#:~:text=In%20the%20production%20of%20Tektronix,application%20of%20too%20much%20heat.
So i think these terminals would allow for a very compact build if you knew how to use them without destroying them. I guess this is why Tektronix used them and they had a way to quickly populate them, too. Which wouldnt concern me but it's always fun to find out why they did what they did way back when.
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Tek specced "about 3%" Silver. "Real Silver Solder" is 30%-75% Silver.
Since Silver is 30-40 times the price of Tin, ~~50% Silver Solder is MUCH more expensive than 3% Silver Bearing.
I dunno if the strips tolerate a huge dose of Silver; except most of the Silver Solders have HIGH melting points and are often (in English) called "brazing alloys" rather than "solder". Solder melts like lead, below red heat. Brazing needs a flame and high-red heat. (In many other languages all molten-metal processes are called "welding". I guess the English had separate unions for iron, copper, tin, pewter.... and their techniques got different names.)