I’m new here, but I feel at home in this thread. I fear I suffer from this disease, showing clinical symptomology in every parameter. It’s not just for electronics. Other hobbies, too. I bought an old South Bend lathe and my wife asked me what I was going to make with it. “Lathe parts.” If a hobby requires expensive apparatus designed to prevent me from retiring, and that gives me an excuse to conduct wholly unnecessary levels of exhaustive research, I’m all in. I just can’t resist. I keep telling myself I’m equipping myself for retirement, but who am I kidding? I’ll never be able to retire at this rate.
Case in point: these last two weeks, I’ve decided the audio junk fixit pile has grown too large and I either need to fix the stuff or destroy it the rest of the way trying to fix it so that I can sell it on eBay as “untested”. And a couple of Mend It Mark videos provided the trigger (this time).
I have a Fluke 115 handheld DMM that really does everything I’m smart enough to need. But nooooo. I decided I needed a bench DMM with 4.5 digits. So, I researched old bench DMMs that were $35 or less and well-made and came up with the highly regarded Fluke 8050, one of which I bought. While looking at that, I caught a glimpse of a Keithley 175, which I liked better (it has auto-ranging), and bought it, too. The Fluke didn’t work (the display turns on but no input or button pressing changes it) and the seller refunded me but told me to keep it. So, I bought another one. It also doesn’t work. The voltage it reads grinds its way over about a minute to the correct value.
Meanwhile, the Keithley 175 worked fine but the soft switches rarely worked. So I took it apart and cleaned those (very easy). That should be good enough, right? I have my new bench DMM, and it’s a good one.
Not hardly. I was still just building up a head of steam. I started researching 5.5-digit DMMs, because shut up that’s why. The Keithley 197 is compact and loved by a fan community here whose thread on that DMM proved compelling. I found one for a reasonable price (but still considerably higher than my initial budget). It’s on the way.
Meanwhile, the dead second Fluke resulted in a partial refund and don’t bother sending it back. So, now I have two Fluke 8050’s on the fixit pile.
This is fun…the fixit pile is keeping pace with the bench equipment.
But in all the research into the dark forest of volt-nut land, the evil spirits lurking therein pulled me inexorably to the darkest corner wherein one is confronted with: HP. In the classes I teach, I use Bill Hewlett’s HP Way as an example of emergent needs-focused systems engineering (do as I say, not as I do), so I always have a soft spot for traditional HP equipment.
And I ran across one of Dave’s blog videos about affordable old 6.5-digit DMMs. He mentioned the HP 3457A as a sweet spot between used price, quality, and function. Why not the 3456A, which is cheaper, I ask? It avoids the proprietary HP parts coding that makes the 3457 harder to service!
Well, there’s the ROM rot issue. Forget that—just avoid the early 2015A serial numbers. Then, there was some issue that affected the 2201A serial numbers. I can avoid those! And up pops a very clean-looking 3456A for a pretty good price (only a little more—but still more—than I paid for the Keithley 197). It had the 2515 serial number, made at least in 1987. That’s downright recent!
And I bought it.
While waiting for delivery, I then found the many videos of people praising the innards of the 3456A…
….while having them apart because they were broken.
About that time, Norovirus struck down the occupants of Chez Denney and I spent a day of fever-ridden bathroom-constrained hallucination about just wanting to measure one more freaking digit! Can’t I just measure one more digit! The HP will be a failure and I’ll have a fixit job far beyond my skills and I’ll have to send it back. Oh, the disappointment!
It arrived today, zooming past the 197 in the postal service’s usual go-slow contest.
In Vizzini’s words, this thing is truly a hippopotamic land mass. My bench is three feet deep But I can see this is going to need an extension shelf. But it’s…
…beautiful. I plugged it in, powered it up, and It. Just. Worked. The self-test shows no errors, the readings are at least reasonable (I haven’t made it out to the shop to compare it to my other DMMs yet). The LEDs are bright and inviting. There are digits galore.
I had to invite my wife down to the basement to admire it. (She declined.)
So, now the bench will have an HP3456A, a Keithley 197, and a Keithley 175. And the two Fluke 8050’s? If I fix them, I’ll sell them.


Rick “on to power supplies—got to have something to measure!” Denney