Electronic Design

Bob's Mailbox

HI BOB,
I have been collecting some new but mostly museum-grade test instruments. Along with purchases from various instrument rental houses, flea markets, and so on, for a while I bid on items in government liquidation auctions. Occasionally, I won. The starting bid was always $50, and some I got at that price. Some went way higher but seldom approached the original list price, and I gave up way before that. Often, the shipping costs to a pickup and forward agent were more than the purchase price. (Check. /rap)

Last year, the government changed the rules and started wanting something called EUC (end use confirmation, or whatever) on anything of interest to me. I filled one of those pain-in-the-you-know-what “Paper Work Reduction” forms. Then I stopped buying anything more. (Check. I hate those lawyers, bureaucrats, nit-pickers. /rap) To my astonishment, during the past few weeks, I have been demanded to fill in more forms for purchases in 2006 as well as 2007. The items included a Fluke 8060 handheld DMM. (When Fluke 8060s are outlawed, only outlaws will have Fluke DMMs. /rap)

Worse than that, I had to return an HP 3400A true RMS (analog) volt meter. It had been suddenly reclassified as a Class “Q” item, which means that it had to be destroyed when I returned it. (What a damn shame. I think I would hide the damn thing at a friend’s house for a couple of years and tell them it didn’t work and I trashed it. I’d lie to save it. Or, I would sell it to a person who would give it away to save it. /rap)

Apparently, in their great bureaucratic wisdom, somebody has concluded that this 1960s technology is dangerous to U.S. national security! Yes, it has this marvelous 10:1 crest factor, when the present day handheld DMMs only have 3:1. But is that a good reason for becoming a secret? Or is it the neon tube chopper/demodulator, which is the one aging component in the design? (Uh, yeah. “We had to destroy the (village) to save it.” /rap) Or maybe the government is in dire need of the nuvistors. There is one in the front end of this meter. (Oh, they better not come after my nuvistors. Mine are matched! I matched them in my matching fixture 40 years ago. /rap)

As it happens, that model of meter was the very first item that I convinced my at-that-time employer in Finland to purchase for our engineering group. We needed it when we developed SCR-based motor drives for our manufacturing machinery. It was around 1968. So, in free distribution worldwide, eventually obsoleted, and now a dangerous secret. How could Bill Hewlett and Dave Packard ever have guessed? (Geez, too bad you can’t tell that to HP. They’d probably get you arrested for harboring a high crest factor! /rap)

Oh yeah, that meter was part of a three-item lot that I won at $50. The refund I’ll get is prorated with the original price ratio of all items in the lot. I think I’ll get $7. The over $200 that I paid for agent services would be treated the same way, prorating, if I had a receipt. The only place that receipt appears is on my credit card statement, but that included actually two lots at the same time—not likely to be sorted out if I even tried.

Another item that I can imagine a little better being recalled is a TEK 1502 reflectometer that I got in a March 2006 auction. There was no mention of destroying it in the recall. I think it is the version that still contains a tunnel diode “heart.” When did you last try to buy a tunnel diode? So maybe even the government can’t waste any of them.

–PELLERVO KASKINEN

HELLO, PELLERVO:
What a nuthouse. It would make Jim Williams sick. Hey, hide the damn things. –RAP

HI BOB,
I was amused by how fast you go from an e-mail answer to your column. (Sometimes they go fast. Others, not. /rap) I assume you are aware that now that you can make a better op amp, the analyzers can get better. (But my (analog) analyzers can measure things better than committed analyzers. Take a look at AN-1485. Go to www.national.com/rap, search for AN-1485, and print it out. /rap) I just finished testing to see how the lead-free solders compare to the audiophile ones. I had to use three LME49740s to test this. (We try to put good plating over the tin, so whiskers will not grow, but a sample of three is not enough to prove anything. Have you seen our official position on lead avoidance and tin whisker avoidance? /rap) The results were not surprising: 63/37 was better than 60/40, 62/36/2, and 96/0/4. Maybe, kind of, not a real clear result. I will let the test samples age to see if anything grows. –ED SIMON

HI, ED:
Maybe you can avoid the tin whiskers, but I don’t think you can make an absolute guarantee based on a sample size of three, times 28 months. That’s barely good enough for a satellite that has to last more than four months. –RAP

Comments invited! [email protected] —or: Mail Stop D2597A, National Semiconductor P.O. Box 58090, Santa Clara, CA 95052-8090

TAGS: Components
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