Test Equipment Anonymous

Look more closely, especially at the other side of the connector (with Fluke blue shroud reinstalled) and see there is a shroud made of - wait for it - perforated card?! Involuntary shudder, as I remember Bulgin connectors. Bulgin plugs. Memories of Quad ESL 57 speakers there. Anyways, the Fluke 80...

Test set up: 2465 set to 50 ohm input. 75 ohm output on the generator. Why hp chose 75 ohm is a mystery to me. The results. Drum roll..... So the symmetry issue is finally fixed. All that's left to do is calibrate the frequency dial. There are adjustments for each range so it should fall into place...

Hey Mike - if you want to get the correct counter to calibrate your square wave generator, there's one on The Bay of Evil now! https://www.ebay.com/itm/306299652398?_skw=hp+524+nixie&epid=19064607187&itmmeta=01JV5BA7JF33H4JGDMAE4TY854&hash=item4750e1c92e:g:W8cAAeSwmIdoImXB&itmprp=en...

MED6753 wrote: ↑Mon May 12, 2025 7:02 pm Calibration was a bit fiddly but finally fell into place. Will burn-in for at least 2 hours then this project is complete.

Oh no it isn't! Not until the spectral purity of that sine wave is checked out on a spectrum analyzer!

Mike, IIRC my 523D was working when last I powered it up - want to borrow it? ;) https://photos.smugmug.com/Electronics/HP-523D-Electronic-Counter/i-NcvQQdn/0/LT68vGN2VDjgbWq9WsJNNb9jhF63mL96ZKCWhTWv4/XL/HP%20523D%20front%20view-XL.jpg https://photos.smugmug.com/Electronics/HP-523D-Electronic-Count...

I broke down and ordered two CE Manufacturing multisection capacitors, the 30/20/20/20 uF at 525 V that's a drop-in replacement for the can that's found in different Dynaco amplifiers. I'm debating back and forth between doing the Dynakit Stereo 70 that I've got plus one Mark IV, or both Mark IV amp...

Yesterday was a long, exhausting day but I did end up making contact with the lady selling the HP 211AR so I ended up heading down to the Niagara peninsula to pick it up after work. It was being sold along with some other test equipment and ham radio gear by a silent key's widow. We ended up enjoyin...

It's been a slow morning at work and I was browsing around on Kijiji and came across a sales listing for an HP211AR which is the rack mount case version of the same square wave generator you've got not far from home for reasonable money and I just messaged the seller now. Hopefully it's still availa...

If it is indeed an Astable Multivibrator then it definitely has an issue because the output should be a square wave and depending on the frequency selected it's a pulse which becomes more of a square wave at the highest frequencies. I'll wait until I get a new 6C4 and see what happens. I doubt the ...

Question for you smart guys. Is that circuit an Astable, Monostable, or Bistable multivibrator circuit? Depending upon the correct answer it may be functioning properly and the problem lies further down the circuit path. From my quick read of the theory of operation in the manual, it sounds like it...

I was looking over things today and noticed something. R29 does not look very healthy. Burnt I'd say. It's a 1.5K, 1W, 1%. I don't see any obvious reason why it would burn unless V5 is drawing excessive cathode current. When I get a chance I'll replace R29 and see what happens. It just so happens t...

Glad to see your replacement meter came, and even more importantly was still there when you got home. You'd think it would be common sense as a delivery person to put a package in at least a somewhat inconspicuous spot if possible. Obviously, I expect too much from people, as common sense is a horr...

I got a shipping notification today, so I should have them by early next week - they're coming from the left coast via USPS. I'll post pics and let you know what I think when I get them. -Pat Cool - I'm looking forward to seeing your thoughts on them when they arrive. On my end, it was the opposite...

That meter looks like it cleaned up really nicely. Do you know of a source of pin plug test leads? I have two meters that use them but no leads. I was going to try test fitting a mini-banana plug connector into a pin socket and see if it fits and is workable but haven't had a chance yet. IIRC Probe...

The 635HV is another I'd never heard of - just looked it up - wow, 6 kV! Are the HV ranges just additional voltage dividers that you plug into and select a lower voltage range using the selector knob, or? (It's not obvious from looking at the pics I found online.) The way it works is the back part ...

Interesting - that's the first I've ever heard or seen of them. Fortunately, I don't have a 260 - used Triplett 630s in HS and so developed an affinity to that breed. Hunted one down years ago; it's buried around here somewhere. Good luck in chasing down the rest of them - that'll be a cool collect...

holy crap med......are you hearing the pissing and moaning from these brits about driving a couple of hours? I think I've told this story before about how two of the British relatives visited when I was a little kid. They flew into Montreal and stayed with my grandparents there and several days lat...

Today's pickup, and I apologize for the mediocre photo that was all I had a chance to get before hopping on the train to a midnight shift, was a Simpson 657 milliohmmeter Add-a-Tester for the 260 multimeters: https://imagizer.imageshack.com/v2/800x600q70/922/j6MYzC.jpg The two cables coming out the ...

That really does look good in the pictures. Did the CRT's display improve once the upgraded rebuilt power supply? If the CRT's worn out, it's got to be something that has to be seen in person because it looks great in the photos.

I guess it's hard to find good technicians whether it's a paid or volunteer environment. Somebody needs to train them. If that isn't possible then have supervision. If that isn't possible (e.g. voluntary organisation) then at least have three people working alongside each other, so that there is a ...

Nice find! $25 can't be beat for a working HP oscillator. Any thoughts on replacing the missing HP logo? Those little badges look like they were prone to falling out and going missing over time with that build style for whatever reason. Brittle plastic breaking or adhesive not standing up over time?...

Those that haven't yet been to the Imperial War Museum at Duxford and the one at London, RAF Hendon Museum and the Science Museum in London all are well worth visiting. I've been to the both the Science Museum and the Imperial War Museum in London, and I'd like to revisit them both and London in ge...

It was actually a well thought out con. Freezer level temperature does affect the crystaline structure of some alloys. For example in aviation after annealling rivets they work harden at room temperature. This can be slowed by keeping them in a freezer. The treated fuse that blew quickly was obviou...

I've seen very high value (100A plus) fuses filled with sand (or something). I assumed it was there for quenching. When it blows you want it to stop conducting, not to continue as an arc. Well, these cigars are 30A, but also "Eaton Bussmann Series Class RK5 fuse, FRS-R, time-delay, dual-elemen...

The eevblog video posted yesterday ( https://www.youtube.com/watch?v=6TYtdpbFWuA ) about fuse characteristics being permanently changed by exposure to low temperature was interesting. He was showing fuses in the context of current shunt overcurrent protection in multimeters. Dave didn't mention any ...