I don’t think I posted a picture of this one but I picked it up locally a while ago.
First order of business, is there a recommended silver solder for working on the ceramic strip mounted parts that’s in current manufacture or do I need to be on the lookout for old Tektronix stock?
Med has is view, I have mine !
Both are 100% compatible though, as I am about to explain
Here goes :
As per the service manual :
" Solder used on ceramic strips should contain ABOUT 3% silver ". So the actual percentage not critical. Just take any silver solder... IIRC when I went shopping for mine on Farnell, you would find solder with silver content in the range of 2 to 3%.
Also :
" Use a 40 to 75 iron, with a 1/8" wedge shape tip ". So they don't like high power irons...hmmm..
Also :
" Ordinary solder can be used occasionally without damage to the ceramic terminal strips. " So, it's not the end of the world.
Also, and this is the most interesting bit I find, that wraps up everything :
" However, if ordinary solder is used repeatedly, or if excessive is applied (ie EVEN when using silver solder ! ),
then the solder-to-ceramic bon may be broken ".So.... what I understand from all that :
- What the root problem is, is not a chemical recipe that would REQUIRE silver content for the ceramic strips to be happy. Rather, what damages the ceramic strips is too much heat /temperature for too long. Tek using silver solder (lower melting point than regular 60/40) AND recommending a low power iron on top of that, is them trying make everything they can to reduce the temperature applied to the strip. That is all there is to it I think.
From that we can conclude :
- If Med never had a problem it's probably because 1) he does rework the same joints 10 times over and over, as why would he need to anyway. 2) IIRC he said the other day his Hakko station was good for everythgin he does however it was showing its limit when used on ceramic strips, was sturggling a bit. Which means his station was unable to maintain teh set temperature... which is precisely what Tek wanted to achieve when using a low power iron (which back then would not be temp regulated I assume, so a low power iron would therefore not be able to maintain a high temp on the strips).
So... to wrap it up, I would say :
1) You may have a better iron than Med's Hakko, so your may be able to hold the tip temps better and therefore more likely to damage/Stress the bonds.
2) No using regular solder will not make the strips explode or suicide, it's not the end of the world.
3) Silver solder is readily available and modern iron are temp controlled. So why not just do the right thing to make sure all stars line-up, for maximum peace of mind : get some silver solder, 3%, you don't need much ot it anyway so cost is irrelevant. Then lower the temp on your iron to match the lower melting point of the silver solder as that's why we are using silver solder to begin with ! If you have a metcal then get a tip set for a lower temp, it's available.