[volt-nuts] 3458A questions

[Dick Moore]

I'm not depending on my 3458 for standards work -- I'm just a volt-nut. Having been through a number of 5-1/2, 6-1/2 and 7-1/2 digit units from Fluke, Keithley, HP, Dana-Racal, and Datron, I finally decided I should take a flyer on a 3458 and get the resolution and perhaps the accuracy that I was wanting. You know the symptoms -- "Is that reading real?" 

I bought one on fleaBay that was said to power on and work. The seller was in NJ and I'm near Seattle, but what the hey -- the price was acceptable at about $2100 and naive me, I thought, well, I can just return it. It showed up non-working, and removing a cover showed a burned up IC in the middle of the analog board and a badly charred board. The listing offered ROR -- in eBay boilerplate -- but the seller claimed that wasn't true, he wasn't taking it back or refunding the money. I took it to PayPal and they got me my money back without any problem, just took a couple of weeks. He got the meter back of course. 

I was a bit discouraged, but then I saw two of them on eBay, clearly from the same seller but with different eBay IDs -- was this a scam? It was BIN, $1600 -- they'd been listed for about 5 minutes when I saw them, and I jumped on the one that looked the cleanest in the pix. A plausible argument was that they were pilfered, but maybe not -- but they clearly wanted to turn them fast. It showed up working and working pretty well, but the display was bad. I ordered a display board and put it in -- $400. Now I could actually get all the readings. Then I sent it to Loveland for the least expensive cal -- they very nicely called me and recommended that I change the A5 ROM board, they thought it was about done -- the tech said the unit was made around the early 90's. I asked them to send it back to me, which they did without a charge for the diagnosis time -- terrific! I ordered the A5 kit and put it in -- $500. I didn't have any way to save the cal data, but I wanted it to go back to Loveland anyway. I sent it and they thoroughly checked it and told me it was working to new standards for various relays, parts, leakages, noise, stability, etc. They sent it back with the cal data -- $500. End of story. A fabulous meter. I don't wonder about measurements, I just make them and believe what I see on the readout. Peace of mind. But I'm not making a living off of this meter -- it's just a volt-nut thing.

Bottom line -- if you're willing to take some chances, buy a well-used machine and then be prepared to spend as much as $2200 to get it right -- that's the flat-rate fix everything that needs fixed and cal it price from Agilent -- that's a very good deal, if the box is really sick. If you want working and cal'ed when it hits your door, buy one of the $5000 - 6000 units that are cal'ed to NIST with a guarantee and a one-year re-cal included. Or of course, spend the $9000 for a new one. In the end, mine was 1/3 the price of a new one and 1/2 the price of one of the used-but-guaranteed ones. I was lucky. Thing is, over the years I spent way more than three grand on other stuff that wasn't as good -- shoulda done right off.

Dick Moore