Test Equipment Anonymous (TEA) group therapy thread

[BU508A]

All the best for your mother.

Get her well soon.

[Mr. Scram]

Nothing exciting. Just a relatively sloppy wet pulse triggering a monostable 

It wasn't triggering at all so holdoff wasn't any use.

I've just spent ten minutes trying to reproduce it now to no avail.

Only thing I can think of that may have caused this is an offset issue somewhere which caused a disparity on trigger level. This would make sense as it went away after cal but I'd have expected to see a zero drift for that. It was unlikely a gain drift either. I'm wondering if the user cal process fucked up when I did it on Sunday?

Edit: anyway got to dump this issue. My mother has just had her cateracts done so I'm off to the hospital now to do the ferrying...

The issue is gone after the most recent self cal?

[Specmaster]

But what confuses me: it comes with a yellow screen. Never saw a Hameg before with a yellow screen. 

Searching for HM-605 pictures on google about 10% has a yellow screen.

I think that Hameg were not the only makers to offer a yellow CRT either, pretty sure that I have seen photos of others as well.

[Specmaster]

It seems that at least Hameg, Iwatsu and LeCroy have made some with yellow screens.

[McBryce]

Tektronix had a Yellow-ish version too, aswell as green and blue.

Btw, did you know that if you buy enough 2465s you'll probably get two or three working ones from all the parts?
https://www.ebay.de/itm/Tektronix-3x-2465-3x-2465A-7x-2465B-Oscilloscope-Ersatzteiltrager/293220066594
(not my sale, just spotted it while browsing)

McBryce.

[Specmaster]

Wow that's huge pile of them.

[mnementh]

Hahaha. I've got the 475 still here. That's just as much of a bastard unfortunately as the trigger drifts as it's warming up. The 465B trigger was much much better than the 465 and 475 were.

Philips and Hameg both trigger reliably without any fannying around or warm up

Edit: it's really embarrassing that an ass end 20MHz scope with bare minimum features is actually ranking high on the "just works" list

These Hameg scopes are not that bad. Used my 203-7 many years and I liked it. Imho the Hamegs are often underestimated scopes.

I would say they are rather good actually. Cheap, well built, well implemented and no “cool tricks” that are difficult to fix. I am seriously considering getting an HM605 if one turns up. That has 60Mhz and delayed timebase. That, the Rigol and a cheap saleae analyser will cover all my use cases without spending a lot more money.

There’s also hundreds of the things here so spares isn’t a problem.

I like the Hitachi V212-222, etc the same way. Decent, reliable, simple. Works for 30 years without a wibble. Not as cheap as that Hameg, but the more compact format is definitely more space-friendly. Also they run cold as a stone; very few wasted electrons.

500ms/div ... 100mV/div vertical.

Self cal has passed and it actually triggers now on 1/2 . Looks like something analogue had drifted off ffs. Literally only did self cal on Sunday. piece of crap.

Looking at Keysights again now 

Directs bd's attention to the first page...

…
9.  Capacitors are Murphy's footsoldiers.
10. The adhesive used to apply a label is always stronger than the label itself.
11. Masochism is endemic, perhaps even mandatory.

Btw, did you know that if you buy enough 2465s you'll probably get two or three working ones from all the parts?    https://www.ebay.de/itm/Tektronix-3x-2465-3x-2465A-7x-2465B-Oscilloscope-Ersatzteiltrager/293220066594   (not my sale, just spotted it while browsing)   
McBryce.

Wow that's huge pile of them.

Yummm... more footsoldiers for my 2465 Army. Conveniently already deployed in the EU theater... 

mnem
*back out into the suck*

[mnementh]

Something I just realized as we've been loading stuff that we've packed for the last few days... aside from oodles of plastic tubs stored on commercial wire shelving, more than half our household is packed in Amazon boxes. With Amazon mailers as padding.   

That is a MFT of pictures of Bezos' dick (the Amazon logo) polluting our collective mental space... 

mnem
 

[bd139]

Bezos likes dicks. He built a flying one 

Back now. Surprisingly slow day today on the TEA thread. Not much to catch up with 

All the best for your mother.

Get her well soon.

Thanks - much appreciated. She's all good even though she looks like a giant bluebottle fly now with the big plastic thing over here eye. I keep making Borg jokes as well

On the Keysight, I've decided I'm too cheap. By the time I've got a unit that's not a turd I'm down £1200. I'm not sure I'll derive that value from it before it breaks or depreciates. I'm slightly less annoyed with the Rigol now the thing appeared to be a cal issue. Plus imagine all the other TE I could accumulate for even half of that 

@mnem: On the Hitachi scopes, good to know. I like their really tiny 50 MHz box, the V509. That's a lot of scope in not a lot of space.

[BU508A]

Thanks - much appreciated. She's all good even though she looks like a giant bluebottle fly now with the big plastic thing over here eye. I keep making Borg jokes as well

SCNR 

[bd139]

Ahh First Contact. Good film. I called in sick to watch that when it came out in the cinema 

[bitseeker]

Continuing my little adventure into RF power meters, since I didn't have an immediate way to confirm that the 478A thermistor mount that I recently got was good beyond the resistance values being "normal", and neither the 432A meter that came with it, nor a 431B I already had were known to be working properly, I, of course, applied a TEA solution to establishing a basis for comparison: I bought a tested and calibrated 432A with 478A and cable.

So, now with a good starting point, I know the following:

1. My unknown 431B will need work since I cannot zero it with the known-good thermistor.
2. My unknown 432A does work properly with the good thermistor.
3. My unknown 478A does not zero using the known-good meter.
4. Both cables are good.

With the two 432A meters, although they do zero properly, they are a bit drifty, especially on the -10 and -20 dB ranges. The newer meter drifts faster than the earlier one that I got, even after being on for over half an hour. I assume that it's an issue with drifty components in the meter, but could it be the thermistor?

0culus, or anyone else with one of these HP meters, does your meter + thermistor (no source attached) quickly drift off zero at or near its most sensitive range?

[Specmaster]

@bd139 good to hear that mum is fine, has she got to have other eye done as well? My mum had to have both done but at different times of course. How about administering her eye drops, is there someone at home with her?

Sent from my POT-LX1 using Tapatalk

[bd139]

Yes other one too. 5-8 weeks they said. She's good with the eye drops. She's as fit as I am, although that's mostly because I could be fitter 

Edit: talking of which I ate the most VILE big mac I'd ever had on the way home. Way too much salad 

[mnementh]

Is there any other kind of Big Mac...? 

mnem
"Spew and a half..."

[Specmaster]

Yes other one too. 5-8 weeks they said. She's good with the eye drops. She's as fit as I am, although that's mostly because I could be fitter 

Edit: talking of which I ate the most VILE big mac I'd ever had on the way home. Way too much salad 

Arh, yes the green stuff is good for you, full of vitamins as my Mum always told me. I'm with you on the could be fitter stakes, but I love my food so [emoji16]

Edit. My Mum was  a vegetarian and grew most of her veg and fruit, all organic. Had 2 sisters and she always used to tell me how she was going to outlive both of them because her healthy diet. Sadly that's not true, she was however 92 when she clocked out for the last time, both of her sisters are still here, one is 100 and the other I think is 95, so maybe too much green isn't that good after all. [emoji849]
Sent from my POT-LX1 using   Tapatalk

[mnementh]

In Nixie News...



I was feeling a bit wibbly after working on the toolbox today... so took a little sit-down to recover. This has been sitting there eyeballin' me for days... so I got brave and plugged it in. When it greeted me with glowy nixie warmth and numbers settling down to within a few digits of zero, I got a little braver and connected the probes to a wall outlet. 

mnem
mrrp?

[worsthorse]

There is a nice looking one for EUR 79.- in .de, ships worldwide (including UK  )

https://www.ebay.com/itm/223635588087

Hey! Here's one for only $600, including shipping!

eBay auction: #183631903580

A bargain for only $10/MHz... 

[0culus]

Continuing my little adventure into RF power meters, since I didn't have an immediate way to confirm that the 478A thermistor mount that I recently got was good beyond the resistance values being "normal", and neither the 432A meter that came with it, nor a 431B I already had were known to be working properly, I, of course, applied a TEA solution to establishing a basis for comparison: I bought a tested and calibrated 432A with 478A and cable.

So, now with a good starting point, I know the following:

1. My unknown 431B will need work since I cannot zero it with the known-good thermistor.
2. My unknown 432A does work properly with the good thermistor.
3. My unknown 478A does not zero using the known-good meter.
4. Both cables are good.

With the two 432A meters, although they do zero properly, they are a bit drifty, especially on the -10 and -20 dB ranges. The newer meter drifts faster than the earlier one that I got, even after being on for over half an hour. I assume that it's an issue with drifty components in the meter, but could it be the thermistor?

0culus, or anyone else with one of these HP meters, does your meter + thermistor (no source attached) quickly drift off zero at or near its most sensitive range?

Yep, the 478A I have (the only one I have) that won't work at all on a 431B meter, is definitely drifty in the sensitive ranges of the 432A. It will settle down a bit after successive applications of the fine zero switch on the 432A. Right now after I just powered it up from cold I had to zero it about 6 times before it settled. Then it just drifts a few dB in either direction.

[bitseeker]

Interesting. I was attempting to characterize mine, but got busy with other things which killed my records. The first hour from cold, at -20 dB range, it drifted full scale. Then, I reset the coarse zero, put it back at -20 dB and hit the fine zero. An hour later, it had drifted about half of full scale. Reset the coarse zero, put it back at -20 dB and hit fine zero. About two hours later, it had drifted past full scale. I wasn't watching it, so I don't know when it hit full scale in order to determine if it's slowing down at all.

So, it's the thermistor that's doing that and not components in the meter?

[0culus]

Interesting. I was attempting to characterize mine, but got busy with other things which killed my records. The first hour from cold, at -20 dB range, it drifted full scale. Then, I reset the coarse zero, put it back at -20 dB and hit the fine zero. An hour later, it had drifted about half of full scale. Reset the coarse zero, put it back at -20 dB and hit fine zero. About two hours later, it had drifted past full scale. I wasn't watching it, so I don't know when it hit full scale in order to determine if it's slowing down at all.

So, it's the thermistor that's doing that and not components in the meter?

I left mine on over supper just now and I found it pegged downscale. 

Does yours drift more when you touch the thermistor body? This is metal part just behind the N connector. Mine seems to move a lot when I apply body heat to this area.

[med6753]

I won this auction. Got a 7A16A coming my way. 

The mere fact that I was the ONLY bidder is beside the point. 

[bitseeker]

  It's good to be solo.

[bitseeker]

I left mine on over supper just now and I found it pegged downscale. 

Does yours drift more when you touch the thermistor body? This is metal part just behind the N connector. Mine seems to move a lot when I apply body heat to this area.

Oh, wow. When I hold onto the thermistor, it goes almost full scale in a matter of seconds. So much for, "Design of the mount minimizes adverse effects from environmental temperature changes during measurement," and "Each mount contains two series pairs of thermistors, which are matched to cancel the effects of drift with ambient temperature change."

Tapping or moving the mount and cable around makes the needle wiggle, too.

I don't know what to expect since I haven't owned these things before. Maybe such sensitivity is normal when set to measure tens of µW?

[worsthorse]

I won this auction. Got a 7A16A coming my way. 

The mere fact that I was the ONLY bidder is beside the point. 

That's good deal!