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In Reply to: RE: Be Gone Old Solder Joints and Sockets! posted by Jonesy on August 05, 2015 at 12:41:23
Nice looking work, but you need to know that through-board eyelets can cause a helluva lot of grief. This construction technique was responsible for thousands of failures of Akai reel-to-reel decks during the early '70s, and very few audio manufacturers used it after that. The problem is that the eyelets don't expand/contract over temperature at the same rate as the rest of the materials (including the solder). Eventually, the solder cracks in a circumference around the eyelet, causing opens and intermittents. The only solution I know is to run a thin piece of buss wire through every eyelet, bend it over on both sides of the board and solder it to the traces. That permanently connects the solder within the eyelet to the traces of the board.
--------------------------
Buy Chinese. Bury freedom.
Follow Ups:
During my misspent youth, I was a bench tech and a major Japanese camera/electronic company used pins rather than plated through holes. Problem was that many of the pins had some kind of coating or plating/corrosion and the solder did NOT stick to the pins when the boards were flowed.
Cold solder joint HELL and with hundreds of pins/through holes per board and as many as a dozen boards per instrument, I spent a couple years removing pins and replacing them with copper wire soldered to each side of the board.
Problem en masse! That must have been tedious work indeed. Honed your soldering skills though I bet.
The eyelets I purchased are meant for PCB repair. I tested them for resistance and used a miniscule of solder paste to ensure adhesion on each.
Still, I can see where dissimilar metals may eventually expand/contract due to temperature, causing breakage. Glad I only needed to do a few of the octal sockets.
The octal sockets are now raised much higher than the board. Was thinking of getting my hands on a temperature probe or gun just to see what sort of temperature swing I get.
As usual I find myself going down the rabbit hole. Admittedly I think I love the hobby part as much as the music.
Cheers!
Jonesy
"I know just enough to get into trouble. But not enough to get out of it."
David Hafler products: ST-70, DH-200, etc. used eyelets on the PCBs, without much grief. FWIW, I think the thermal issue is important with Octal based power O/P types, where chassis mounting is (IMO) "best".
Perhaps using a strong solder is the practical solution. "Rat Shack" (R.I.P.) carried a copper bearing solder that "Doc B" liked/likes. Another copper bearing solder is Cardas Quad eutectic, which has a reputation for low shrinkage on cooling.
Eli D.
What do you mean RIP?
They are still in business.
DanL
Ahhh. Good to know.
What about all the original through-board connections that I didn't have to replace. I'm guessing they would benefit having a wire through them and similarly soldered to top and bottom traces?
Cheers!
Jonesy
"I know just enough to get into trouble. But not enough to get out of it."
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