|HP-34C in pieces, start betting pool, soldering SPICE calc?|
Message #1 Posted by Norm on 25 Apr 2003, 10:09 p.m.
Over at my household, I started the day thinking I would clean up an HP-34C. Now its in pieces all over the place.
Right next to the computer here, piles of little keys, clips, plastic case parts, its starting to look pathetic.
Anybody want to start a betting pool for whether I get it back together ?? If anybody bets against me and I get it together, they have to mail payment within 5 days.
I paid a high price for this HP-34C, and the guy said it was perfect.
Well, no sooner do I try operating it a few minutes, and its quite unreliable. Just flaky, acting real flaky.
Now, this is in keeping with the early SPICE calculators. Are we really sure that Carly wasn't working there earlier, maybe as a junior engineer? I mean, this thing about chips stuck into the unit without any soldering. That's dumb, real dumb. It's Carly-dumb.
I stripped it all the way down, so that the IC's all fell loose. I see oxidation on pins of the 3 memory chips. I tried soldering to them, and you can't solder to them, not unless you use the tip of the solder iron to rub each pin for awhile. Obviously this is the failure mode for the early SPICE units, the oxide on the pins prevents contact.
So I am experimenting, folks. I'm converting this UNSOLDERED product to a SOLDERED product. I'm about 60% done. It looks difficult, but promising.
There was a fork in the road, I decided that I would accept an inferior cosmetic appearance, for a more reliable exterior performance. I mean, I can't realistically even remove the solder flux afterwards, so it wont look real pretty, but who cares, you have to tear it all the way down to see the solder and the flux.
The Leica self-illuminating low-power stereo-zoom microscope is real handy. There's a certain model that can be had brand-new for $850 , and its zoom, x7 to x 30. It helped me make sure that each connection was solid, esp. with the solder-resistant pins on the 3 memory chips.
WHAT'S KILLING me is I want to replace the 22uF electrolytic caps, figuring they'll go dry soon. I drove to the usual watering holes,here in Seattle. One folded, the other moved. Kind of pathetic, really, a country where there's only one or 2 stores that you could go to buy tantalum capacitors, in a city of 3 million.
No, Radio Shack doesn't count.
I would appreciate any input from those who have tried, or refused to try, converting an unsoldered unit to soldered.