Products > Test Equipment
Test Equipment Anonymous (TEA) group therapy thread
Vince:
Oh wow, congratulations !!! :-+
So looks like you made your own PCB at home, with nasty chemicals and all, like in the old days ?
I always like it when SMD is used on such a PCB.... looks so weird, paradoxical.... it's like finding SMD components in a '60s hollow state Tek scope...
Maybe once my garage is built, I will start doing my own etched boards for when I can't wait for chinese companies to send them, and/or when even cheap chinese, is still too expensive or too fancy for a particular need.
Well done on the bargraph ! I had forgotten about these things somehow ! Looks cool, retro as hell.... just perfect ! Those specialized IC driving them, made it a so easy to implement them... nice to see you can still buy them today ! Or maybe you had old stock...
I am still debating whether or not I want to build an ammeter into my load, when I get to build a nice enclosure for it. Sometimes I feel it's unnesseray as one can just wire a DMM next to it if need be, and get an accurate reading. But sometimes I also feel like... like I want some semi-accurate reading just to see what's going on in the load, yet I don't want to bother with a DMM that takes space on the bench, and extra wires.
So I was thinking of embedding a 3200 count ready-made module but... it might feel too much... like trying to stick a DMM inside the load, a bit pretentious.
So... a bargraph would be cool. It would give enough resolution to give me the coarse indication that I am after, yet it would not look too "sophisticated" like digital display would... and it would look nicely retro.
Yeah.... a bargraph could be an idea ! I could even have two of them... a coarse one from 1 to 10A, and another one from 0 to 1.0, with 100mA resolution...
Thanks for the idea ch_scr ! ;D
Peter_O:
I've had a cotemplative afternoon doing a nearly full calibration of my HP3310A from 1969 and listening to Gardiner's recording of Monteverdi's Marian Vespers . :-/O
Just some snow is missing.
Skipped only the distortion point, because I was to lazy to haul the 35665A onto the desk again.
I played with that topic some month ago and the 3310A was within spec back then.
How does one measure THD with a SDS2000X+? :-//
All other parameters were within spec already, but of course I did a proper adjustment of the frequency wheel. :-)
Acc. to stickers the last calibration was done in the 80s. Nearly nothing was out of spec. That little guy is a joy to play with. :)
ch_scr:
We've got a pcb mill at work that "sometimes needs checking if it still works" ;) (Really lucky there) It's nice since you also have the holes drilled already. It's less nice, since with isolation milling, you get an gap around your traces and the "spare copper" then has to be picked off with tweezers and hot air. I've had a few bargraph IC and wanted to do something with them for a long time already, so this came along just right. For 10A, the resolution is barely not really good enough. Good enough for a quick check of a power supply though. A small panel meter should be "just right" and still look quite retro.
@Peter_O: An FFT might give a good indication on where the distortion is lowest. At least a lot better than "staring at the sine". Limited by instrument distortion obviously, an 12bit one would really shine there...
Edit: IIRC "staring at the sine" gets you to around "20dB to the highest harmonic", but can't tell any better than that. An FFT even on 8 bit should be quite a bit better...
tautech:
--- Quote from: ch_scr on December 10, 2022, 08:38:41 pm ---................
@Peter_O: An FFT might give a good indication on where the distortion is lowest. At least a lot better than "staring at the sine". Limited by instrument distortion obviously, an 12bit one would really shine there...
--- End quote ---
10 bit mode is available up to 100 MHz. ;)
duckduck:
Ebay drama.
I bought a HP 8656A Signal Generator (0.1 - 990 MHz), but when I received it, one of the handles was cracked, and the cooling fan was locked up solid. There was a huge amount of dust in the unit, as if it were operated outside for an extended period. I spun the fan with a popsicle stick and it did eventually turn under its own power, but it sounded like a brake rotor being machined. The bearings were clearly bone dry and dirty. I complained (politely) to the seller and he said that I should file a claim with UPS. I was hoping that we could work out a refund for a replacement fan and handle ~USD60. I'm not doing the work to file a fraudulent claim with UPS for a fan that didn't work when he packed it so I'm using the nuclear option and returning the unit. Ebay has already given me a pre-paid US Postal Service label. Damn shame, as the unit seemed to work otherwise. Latest date code I found was 8349, so perhaps a late 1983 build date.
I'll keep my eye out for another signal generator that can do UHF that doesn't cost an arm and a leg and a kidney.
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