Test Equipment Anonymous (TEA) group therapy thread

[AVGresponding]

Look, what just showed up in the ebay Kleinanzeigen:
https://www.ebay-kleinanzeigen.de/s-anzeige/agilent-technologies-34172a-dmm-calibration-short/2088597742-168-23789

Well, I was lucky to get this Agilent 34172A Calibration Short one from eBay Kleinanzeigen.
Here are some pictures from the inside.

Also posted in the thread about calibration shorts.
https://www.eevblog.com/forum/testgear/diy-34401a-calibration/msg4148476/#msg4148476

How much did you end up paying, if I may ask?



EDIT: Here's mine btw, Wago plugs, 2.5mm² solid copper wire, big solder joint. I may try to make another using crimping, to reduce thermal EMF.

[HighVoltage]

How much did you end up paying, if I may ask?

30 Euro incl. shipping.
I had to explain to the seller what this is, since he had no clue at all.

[Specmaster]

I think CNG is not a suitable fuel for motor vehicles, in the event of crash or a fire, it has the power to either demolish a whole block a become flamethrower if fitted with PRV.

Yeah, the only crazier thing would be to replace CNG (~39GJ/tonne) with something even more energetic like Diesel (~45 GJ/tonne) or Petroleum (~47 GJ/tonne).

Or even want a BMW, sorry C 

Thats' OK, as a Skoda driver by choice we can tell you're not really interested in cars. 

BTW Skodas burn just as well as BMWs:

Back in the day, cars bursting into flames was something we dismissed as "Hollywood BS".
Cars would be in the most horrific accidents, to the point where they looked like stomped on beer cans, but still couldn't be coaxed into going "woompf".

Certainly, on occasion, cars would have fires under the bonnet/hood, but they were remarkably sedate affairs, compared to the Hollywood version.
Modern cars are deservedly touted as safer than those of days past, but one thing which seemingly has deteriorated, is the fire safety in collisions.

I put this down to higher fuel pump pressures, combined with the fact that they are all electric pumps.
The battery connection to the pump is still intact, so it continues to pump, squirting fuel all over the place from severed fuel lines.
The old mechanical pumps stopped when the engine did, as they usually do if mangled in a crash.

That is a very good point in fact, it is very difficult to get gasoline or petrol in a car's fuel tank to actually explode, as there is generally way too much fuel and not enough oxygen. It will burn but not explode.

[tggzzz]

My short is one of these: https://www.ebay.co.uk/sch/krasimir.k/m.html

No solder involved.

[Peter_O]

Some months ago I rescued this litte guy.
Now I want to bring it up to speed.



The friction wheel is missing at the frequency dial.
I'm searching for clear pictures. Best I could find so far is the video of Curious Marc:
[url=https://youtu.be/4TFSBH4AEmg?t=797]]https://youtu.be/4TFSBH4AEmg?t=797]https://youtu.be/4TFSBH4AEmg?t=797

From That it seems to be just a disk with some kind of rubber at the front that presses against the scale wheel from behind.
I plan to print a wheel, cut a rubber disk from 'something' and glue it.

Any better ideas or better pictures?

Looks similar to the setup on my 334A Distortion Analyzer. I'll take some pictures later.

They are moulded onto the shaft, with a spring pushing it against the main dial, this is from my 333A distortion anaylzer, the one with the smashed meter.


Could also have a look at the 3310A here, that one is probably slightly smaller than the wheel on the 333A.

David

Any better ideas or better pictures?

Those are useful. I used mine in VCO mode to simulate part of a 4-20mA device.

Try plumbing washers or o-rings.

Note that the rubber washer is behind the wheel. Make sure both knobs spin freely, or the washer won't have enough friction to move the main control.

(see same quote above)

That is basically correct.

It is a hard plastic, as shown below and in factory's picture. The "ledge" looks as if it aligns with the edge of the dial, but I'm not convinced of that, neither am I convinced it is important.

Internally a bronze leaf spring gently pushes the knob's stem outwards to provide gentle pressure against the dial. The light pressure ensures it slips easily when the main dial is rotated. That might not work as well if it was "sticky" rubber.

Looking at your picture, it might be worth considering seeing if a thick rubber tap washer would fit into the knurled recess visible in your stem, e.g. https://www.amazon.co.uk/Assortment-Rubber-Washers-Basin-Shower/dp/B07Q3WZQHK

Any better ideas or better pictures?

Two pics of my 3310A are attached. The plastic is the same as the plastic of the knob itself. No rubber. The shape is slightly conical and the complete axis is spring-loaded to push the disk of the fine tuning knob against the dial.

Some pictures of the fine tuning mech from the hp 3310A function generator, also used on 3310B, the shaft has the plastic disc moulded on to it, the same as the control knobs and was probably made the same way.



1 The top surface is angled, the one spec pictured has worn down quite a bit to have a flat on the edge.
2 For comparison, the shaft with moulded disc from 3310A on the left and the larger one from the 200CD tube oscillator on the right.
3 A failure mode of these (200CD), it has cracked, will probably fall apart same as the controls do.
4 And finally, the complete fine tuning spring mech from the 207A sweep oscillator.
(Peter_O: Pictures rearranged to save space)

David

A big thank you to all of you! (Hope I haven't overlooked anybody, thank's to you too!) and for taking the effort!
Highly appreciated!

For other readers with the same problem: Do follow back the links to the original posts of the guys above, because some of them contain more pictures attached!

The shaft of my 3310A is running smoothly and the spring pressure seems to be fine too.
With all your high quality input I'll start my experiments and will come back here to report.

Thx a lot again!

[DC1MC]

How much did you end up paying, if I may ask?

30 Euro incl. shipping.
I had to explain to the seller what this is, since he had no clue at all.

Holly crap, 30EUR for this piece of garbage  , probably new was something like 200 from Agilent, hopefully that anemic tinned piece of wire was manually selected and aged by Agilent or else there is no justification to cost as much.

And to consider that in another thread there were people designing these by using finite element analysis for micro-currents distribution and getting funny X-man shapes and Agilent just soldered a piece of miserable wire, not even bother to clean the flux, SMH.

At leas you've go a nice branded box out of it  .

Cheers,
DC1MC

[Cerebus]

<snip>

Thats' OK, as a Skoda driver by choice we can tell you're not really interested in cars. 

<snip>

Hah hah, on this occasion you couldn't be more wrong if you tried, my car was chosen for many reasons and cost was definitely not one of them. My car had to be many things to me on business and personal levels and even today it does not disappoint, for instance it has as standard foot rests for the rear passengers, it is larger in the rear than many limousines. You really should check out today's Skodas, there are no longer the joke of car industry like they used to be. 

To quote Mandy Rice-Davies: "Well, 'e would say that. Wouldn't 'e!".

To be a Skoda driver you have to be prepared to be the butt of many a joke. Still, at least you've still got Lada and Trabant drivers to take the mickey of. 

[mnementh]

...BTW Skodas burn just as well as BMWs: 

Back in the day, cars bursting into flames was something we dismissed as "Hollywood BS".
Cars would be in the most horrific accidents, to the point where they looked like stomped on beer cans, but still couldn't be coaxed into going "woompf".

Certainly, on occasion, cars would have fires under the bonnet/hood, but they were remarkably sedate affairs, compared to the Hollywood version.
Modern cars are deservedly touted as safer than those of days past, but one thing which seemingly has deteriorated, is the fire safety in collisions.

I put this down to higher fuel pump pressures, combined with the fact that they are all electric pumps.
The battery connection to the pump is still intact, so it continues to pump, squirting fuel all over the place from severed fuel lines.
The old mechanical pumps stopped when the engine did, as they usually do if mangled in a crash.

Ummmm.... no.

Ever since we moved to EFI with electric pump in the tank, the pump has been controlled by an inertial "swat switch" that kills power to the fuel pump if the car takes a hard enough swat. 80s-90s or so. In fact, when the tech was new, it was a common point of failure.

Nowadays we have ECUs that control the fuel pump; they monitor CPS and don't turn the fuel pump on until they "see" the engine RPM, and if that goes away, the pump is turned off. Gas or diesel engine, doesn't matter. They all have this.

What they do have that is different is check-valves in the fuel system that keep fuel pressure from bleeding down when the engine is off. This is why you can "bump the key, start" on modern cars. This can allow a small amount of fuel to spray if a fuel line is ruptured or burned through, as they often have plastic fuel lines. In theory this can help spread fire... in practice, there is already so much flammable stuff under the hood it makes little difference.

No, the main reason they burn like a tallow log is two things: High percentage of plastic everywhere, and plastic fuel tanks which will eventually melt through and allow fuel to leak out. The difference though is they keep the fuel cool longer, so better chance of the Fire Dept getting there before it leaks out, and less likely to actually explode or BLEVE in that time like a steel tank which is essentially a pressure cooker when in a fire. Plastic tanks and fuel lines are much tougher than steel in cases of impact damage though... so less chance of rupturing and starting a fire at those points.

Things change. Risks change. The way we deal with things like fires evolves.

mnem
The only constant is change.

[Cerebus]

Back in the day, cars bursting into flames was something we dismissed as "Hollywood BS".
Cars would be in the most horrific accidents, to the point where they looked like stomped on beer cans, but still couldn't be coaxed into going "woompf".

Certainly, on occasion, cars would have fires under the bonnet/hood, but they were remarkably sedate affairs, compared to the Hollywood version.
Modern cars are deservedly touted as safer than those of days past, but one thing which seemingly has deteriorated, is the fire safety in collisions.

I put this down to higher fuel pump pressures, combined with the fact that they are all electric pumps.
The battery connection to the pump is still intact, so it continues to pump, squirting fuel all over the place from severed fuel lines.
The old mechanical pumps stopped when the engine did, as they usually do if mangled in a crash.

The vast majority of vehicle fires that I have either witnessed personally, or seen reported, are not in collisions, they are in vehicles either under way normally or just standing at the side of the road parked. Two I've seen personally in recent years were a Ford Focus that just caught fire while it was driving along sedately in the near side lane of a quiet local dual carriageway (the A1020 beside Royal Albert Dock), and a Vauxhall parked unattended at the side of the road.

As far as fuel pumps continuing to run after an impact, generally they are designed not to. On recent cars automatic disconnect systems isolate power if there's a significant impact; I think this may even be mandated in Europe.  On my car, if the airbags fire there's a pyrotechnic fuse that also blows and isolates the whole electricity supply except the for battery supply to the built in emergency mobile phone transmitter that automatically calls for help.

Edit: Just checked the workshop manuals for my old, 1997 vintage, car and even that has a simple inertia switch that cuts all the power to the engine electronics in the rather simplistic case of rapid forwards deceleration.

[AVGresponding]

How much did you end up paying, if I may ask?

30 Euro incl. shipping.
I had to explain to the seller what this is, since he had no clue at all.

Holly crap, 30EUR for this piece of garbage  , probably new was something like 200 from Agilent, hopefully that anemic tinned piece of wire was manually selected and aged by Agilent or else there is no justification to cost as much.

And to consider that in another thread there were people designing these by using finite element analysis for micro-currents distribution and getting funny X-man shapes and Agilent just soldered a piece of miserable wire, not even bother to clean the flux, SMH.

At leas you've go a nice branded box out of it  .

Cheers,
DC1MC

We've had the clean vs no clean argument re flux in another thread. Me, I'd clean it, but apparently it's a waste of time...  https://www.eevblog.com/forum/testgear/keysight-34465a-reliability/50/

My short is one of these: https://www.ebay.co.uk/sch/krasimir.k/m.html

No solder involved.

Yeah, I just needed something quick and dirty to see if the Keithley 2000 would pass its self-tests. I want to try and make a new one, I think I can crimp the wires together instead of soldering, by using some yellow crimp lugs with the lugs cut off. That way I'll have copper to copper, with just the crimp itself with tin plating, and not being part of the current path.
Obviously I need better banana plugs too, hard to find pure copper with crimp/screw terminations though, they seem to be mostly solder connection. More digging required!

[mnementh]

Well, I was lucky to get this Agilent 34172A Calibration Short one from eBay Kleinanzeigen... 

Mmmhmmm... not exactly awe-inspiring, is it...?

Am I the only one here already designing a PCB with fat, equal-length traces and gold-plating in my head...?   

mnem
Now where to source gold-plated nuts... 

[Vince]

Well, I was lucky to get this Agilent 34172A Calibration Short one from eBay Kleinanzeigen... 

Mmmhmmm... not exactly awe-inspiring, is it...?

Am I the only one here already designing a PCB with fat, equal-length traces and gold-plating in my head...?   

mnem
Now where to source gold-plated nuts... 

You are not trying really hard are you ! 

https://www.ebay.fr/itm/392112941667?hash=item5b4bc0aa63:g:jgcAAMXQltxQ6VjG

[BU508A]

Obviously I need better banana plugs too, hard to find pure copper with crimp/screw terminations though, they seem to be mostly solder connection. More digging required!

Not pure copper but high quality ones: Stäubli MC MultiContact 22.1053


Available at RS https://de.rs-online.com/web/p/bananenstecker/2263095
or Bürklin https://www.buerklin.com/en/4-mm-Panel-plug-Screw-connection-4-mm-red-22-1053/p/12F168

[DC1MC]

Here's my Chinesian contribution, still better that that POS:

eBay auction: #https://www.ebay.co.uk/itm/284443493043

[factory]

Something to distract from the regular autoshite discussion, a cheap & slightly tatty looking 54600A scope for approx $50 including shipping in the US, I saw it last night, but can't work out why it hasn't sold. 

https://www.ebay.com/itm/304467178603



David

[m k]

Yeah I hope that's it.  I have just ordered x3 NOS 6AQ5 from Ebay France, so hopefully I shall receive them late next week all going well.

30 Euros shipped. 10 Euros per tube. Not cheap by my wallet standards, but not crazy expensive either, for NOS tubes I mean.

Best deal was 4 NOS ones for 18 Euros shipped, but they come from Ukraine so delivery time, or delivery at all really, is unknown. I don't want to waste 18 Euros down the drain nor wait 3 months to get them 

So hoping to get my tubes late next week then. In the meantime I will resume work on the Rochar Nixie DMM  I think

How fast are your peek hold meters, can't you expect some results from them?

[factory]

Here's my Chinesian contribution, still better that that POS:

eBay auction: #https://www.ebay.co.uk/itm/284443493043

Link is borked, not that I want that one.

Is there any reason why these couldn't be made from a square of regular copper PCB, or even a square of copper plate?

David

[vk6zgo]

Yeah, the only crazier thing would be to replace CNG (~39GJ/tonne) with something even more energetic like Diesel (~45 GJ/tonne) or Petroleum (~47 GJ/tonne).

Diesel is surprisingly inert; I've sprayed it across hot engines when bleeding injectors but I wouldn't do that with petrol (and probably not LNG).

Inert and "has a relatively high flash point" are not the same thing. I was around then someone foolishly incinerated a can (metal 5L type) that had a very small amount of red diesel left in the bottom (~50ml). The ensuing explosion was non-trivial, but fortunately did no harm.

The individual responsible, Nick, also once tried to 'pep up' a damp and lack-lustre camp fire by tipping petrol on it. Obviously there's something to owning a Norton Commando that rots your brains because both the Commando owners I've known [Nick and one other] were prone to bright ideas of this ilk.

This explosion you refer would have been the same with or without the red diesel which is only small amount of dye added to enable law officers to distinguish between diesel used for road use and therefore has had the proper added taxation paid, and diesel used for a purely off-road use such as farming, and this diesel has the red dye added.

https://www.utilitysmarts.com/automobile/diesel/whats-the-difference-between-red-diesel-and-regular-diesel/

A 5 litre can with a small amount of water would probably explode, too, but it might take a tad longer.

During WW2, my Dad worked at a foundry where salvaged bits of steel stuff were placed in a furnace & melted down for the War effort.
One day, a massive casting which had obviously been sitting round in the weather for years, turned up.
Partway along it was a small hole, sealed with a steel screw in bung.

In it went, the furnace as fired up, it got up to temp, & suddenly, there was a deafening bang, & something flew through  the top of the furnace, knocking a decent sized hole in it.
Dad, & all the other veterans of the Kaiser's War, hit the deck!

Of course, the Military were all over it, but it turned out to not be Japanese Commandos, or a "5th column", but simply that there had been a small amount  of water, somewhow captive under the screwed bung.
The resulting superheated steam blew the bung out of the moulding & through the top of the furnace.

Of course, that would be quite a few orders of magnitude more powerful than a bit of something in a can!

[BU508A]

Here's my Chinesian contribution, still better that that POS:

eBay auction: #https://www.ebay.co.uk/itm/284443493043

Link is borked, not that I want that one.

Is there any reason why these couldn't be made from a square of regular copper PCB, or even a square of copper plate?

David

This one is working: https://www.ebay.com/itm/284443493043

UK version: https://www.ebay.co.uk/itm/284443493043

Maybe because of thermal mass. A copper plate will take much longer to reach equilibrium than a PCB with some copper traces.

[mnementh]

Something to distract from the regular autoshite discussion, a cheap & slightly tatty looking 54600A scope for approx $50 including shipping in the US, I saw it last night, but can't work out why it hasn't sold. 

  https://www.ebay.com/itm/304467178603         David

Probably because it's one of the low-spec models; 20 MSa/s vs 200 MSa/s or 1GSa/s, and only 400K depth vs 1Mb, 4Mb or 8Mb.

Essentially a digital-display analog scope at those parameters. 

   

Mine now, tho... at that price, it's a 54657A GPIB/Data Acquisition module for $60 that happens to come with a 54600A parts mule attached. 

https://xdevs.com/doc/HP_Agilent_Keysight/HP%2054657A%2C%2058A%2C%2059B%20User.pdf

   

Spank you... spank you vurry muuuuch!     

mnem
And I might actually get to play Tetris on it!

[vk6zgo]

HP 120B update

So I stole a 6AQ5 and 12AU7 from on of the type 515.

Result : no HV ! I used my HV probe and probed directly at the connector that plugs at the back of the CRT. I get ZERO. No HV-ing going on, not a sausage 

Bad tubes ? As I said it's not like I have a zillion to try out ! 

So that's were I am now, trying to probe on that HV board to see if I can troubleshoot it, hoping my tubes are good and there is something else wrong with it... hopefully not a burned HV transformer 
Problem is that access to that board is not ideal. I can get to its bottom because of the way it's installed in the chassis. I can only probe the top, and that's not easy as most interesting components are by the read panel. Hard to get probes down there, or see what you are doing really. Also, the caps mostly can't be probed as they sit flush on the board, their terminals are not exposed 

You could swap the HV control tube with one of the others in the 120B, the other might be a problem as it's the oscillator tube. Also check the solder joints on the tube sockets, had many bad joints from thermal cycling, more of a problem with the higher power tubes.

David

Swapped the contorl tube / 12AU7 no luck.

Swapped the oscillator tube / 6AQ5 ... well no I can't. Both the one in my second type 515 and my type 310A which I resorted to opening up out of desperation, are cooked... 100% black inside. I tried them anyway, no luck.

So basically the 6AQ5 I pulled from my first 515 is the ONLY such tube I have here that's not black... it's crystal clear and I can see that at the very least, it lights up. Better than nothing I guess.

So I will or a new tube or two very soon but of course that will take time to get to me. So in the mean time I will pretend that my tube works and try trouble shooting the board.

- I checked all power supply going to that board, board does get all the supplies it needs, so that's good. That includes the unregulated 420V that goes to the primary of the HV tranny. Yes tranny again, transformer this time not transistor 

- Zero oscillation going on : HV probe says zero volts on the secondary side, and when I scope the board, I see only DC voltages, zero sign of activity.

- I measured DC voltages as indicated on the schematic below, around the 2 tubes, i.e 3 elements : pentode and x2 triodes.  DC levels are 100% completely wrong. See measured levels indicated in red. So if we look at the two triodes : both are fed with 300V, and both are supposed to have about 90V on their anode. But, in my case not at all. Get near zero (2.8V) and the other near B+ (300V and the rail is at 304V).
So one Triode is conducting like mad, and the other is not conducting at all, and it sits like that, stable.
As for the Pentode / oscillator tube, it's control grid sees 0.8V instead of negative 123V !
so no wonder it does not work... now the problem of course is that it's a close-loop system, so no way to know what element in the loop is causing the entire loop to fail.


So now what to do...

Checking solder joints yes but not easy as pulling the board from the chassis looks like it will be a major tear down, looks quite involved....

Short of having another oscillator tube to swap, I will make the hypothesis that it's either bad joint as you said, or some passive component that just died.
One thing that might point in that direction is that now I think of it, the brightness control used to have bugger all effect on bruightness. It had as I said effect on the pitch and loudness of the arcing sound if that's what it was, but it did not have much effect on brightness.. it was always very bright.
So right there, we can say that some component or joint in the HV board was not good...

Wish me luck.....

It is quite common for perfectly functional 6AQ5s to be black inside----I got caught with that the first few times, too!

[TERRA Operative]

Something to distract from the regular autoshite discussion, a cheap & slightly tatty looking 54600A scope for approx $50 including shipping in the US, I saw it last night, but can't work out why it hasn't sold. 

  https://www.ebay.com/itm/304467178603         David

Probably because it's one of the low-spec models; 20 MSa/s vs 200 MSa/s or 1GSa/s, and only 400K depth vs 1Mb, 4Mb or 8Mb.

Essentially a digital-display analog scope at those parameters. 

Mine now, tho... at that price, it's a 54657A GPIB/Data Acquisition module for $60 that happens to come with a 54600A parts mule attached. 

https://xdevs.com/doc/HP_Agilent_Keysight/HP%2054657A%2C%2058A%2C%2059B%20User.pdf

   

Spank you... spank you vurry muuuuch!     

mnem
And I might actually get to play Tetris on it!

Are these software/hardware unlockable? Or is it what it is and no way to upgrade with this one trick HPAK hates?

[mnementh]

...Mine now, tho... at that price, it's a 54657A GPIB/Data Acquisition module for $60 that happens to come with a 54600A parts mule attached.

Are these software/hardware unlockable? Or is it what it is and no way to upgrade with this one trick Agilent hates?

Great question. I have no idea; but it'll be lots of fun tearing them both down side x side to find out! 

mnem
This space [    ] left intentionally blank.

[Kosmic]

Here's my Chinesian contribution, still better that that POS:

eBay auction: #https://www.ebay.co.uk/itm/284443493043

Link is borked, not that I want that one.

Is there any reason why these couldn't be made from a square of regular copper PCB, or even a square of copper plate?

David

This one is working: https://www.ebay.com/itm/284443493043

UK version: https://www.ebay.co.uk/itm/284443493043

Maybe because of thermal mass. A copper plate will take much longer to reach equilibrium than a PCB with some copper traces.

+1 to what BU508A just said. To avoid thermal EMF, you want a short with a low thermal mass to reach the temperature of the connectors on the multimeter quickly.

Also notice the low gauge wire used on the rustic Agilent short.

[tggzzz]

UK version: https://www.ebay.co.uk/itm/284443493043

Located in Shanghai, arrives mid-June to mid-July!

Probably faster to learn how to mine Cu and gold-plate Ag