Comments on: Interesting Bits of Old Motherboards

By: Fred Jodry

Fred Jodry — Wed, 24 Jun 2009 17:02:03 +0000

INTJ, to renew your solder braid, tooth brush it with clear vinegar, rinse then dry it, then add a stripping of your appropriate soldering flux. Voil\a! Same advice as Keith above. Let me know if you guys mail parts trades.

By: Keith Neufeld

Keith Neufeld — Tue, 23 Sep 2008 11:34:42 +0000

INTJ, a heat gun is your friend. Regarding the solder braid, I've had trouble with some recently too. I noticed that it was old and all the flux had flaked off -- refreshing it with wet flux (a dip or a drop) makes it good as new.

By: Mr. INTJ

Mr. INTJ — Tue, 23 Sep 2008 08:14:44 +0000

I’ve got loads of discarded boards with all kinds of through-hole components on them, but I’m having a lousy time removing anything with more than three leads.

I’ve tried a solder sucker and desoldering braid. On really small pins, the sucker is awkward and I’m usually not quick enough. The braid just doesn’t seem to absorb much (could it be too old?)

I have a new variable-temp soldering station with a pencil-tip iron. I was trying to remove some really big electrolytics from a board at one point, and noticed that I couldn’t melt the solder around the leads. Mind you, they were thicker than your average leads, but I had my iron turned up to max and had given it plenty of time to heat up… maybe my iron is a dud…

I was thinking of waving a small torch across the back side of the board while gently pulling on the desired part on the other side of the board. I don’t mind toasting the board – it’s the odd part that I want (due to the nasty vapors, I’d do it outdoors of course). This weekend I calculated the cost of the bottled fuel (propane, MAP, whatever), and realized that I’d have to come up with something else…

How do you guys do it? Do you have special desoldering tools like hot-tweezers, or am I missing something?

Thanks.

Mr. INTJ

By: Joel Ewy

Joel Ewy — Fri, 05 Sep 2008 19:24:49 +0000

Of the two other boards, one has already had many of its socketed chips
removed (I may still have them…), and the other was non-sampular.

JCE

By: Keith Neufeld

Keith Neufeld — Fri, 05 Sep 2008 16:33:24 +0000

Dave, good eyes! I hadn’t noticed that, and there’s another on a 16-pin chip to the right of that.

Joel has several more of these in better condition — we’ll have to check whether they were all made using stamped samples.

By: Dave

Dave — Thu, 04 Sep 2008 14:49:34 +0000

Whoa! Did you notice the stamp on that ethernet controller chip?
“Engr-Sample”? I bet you don’t see that very often, especially on
production boards.

Interesting mix of DRAM chips. Most systems I’ve seen have used the
same manufacturer, but these seem to be a mix of manufacturers. At
least it has parity.

Dave

By: William

William — Thu, 04 Sep 2008 01:56:31 +0000

Wow, these pics bring back memories. I remember the dual sockets for cache and such, that was pretty common back in the 8088/286 days. Seeing these old boards reminds me of repairing a motherboard back in my college days. I was too poor to buy a new board so I spent several evenings with a multimeter tracking down what turned out to be a faulty diode. After a quick trip to Radio Shack I was back in business, boy was I proud!