Test Equipment Anonymous (TEA) group therapy thread

[Cerebus]

Imaging yourself sitting as a passenger in a RHD vehicle on a German autobahn, with a notorious alcoholic at the wheel who can't even drive when he's sober. One of the greatest horrors I've ever been through.

A former colleague, Frank, used to drive a LHD car on British roads. I've been a right front seat passenger in it any times and Frank is a good, eminently trustworthy, and sober driver; it still gave me collywobbles every time we did it. Every three seconds I'd find myself trying to steer, brake or accelerate. It was fine if I was in either of the rear seats, but being in "the driving seat" when it wasn't in fact a driving seat is most, most uncomfortable. I've also been a passenger in exactly the same seat in a LHD car in Germany while negotiating the route from Ratingen to central Dusseldorf and vice-versa many times and didn't once find myself trying to brake or steer like I did in Frank's car.

[BU508A]

Echoes from a distant past

Part five - The Rohde & Schwarz vacuum tube millivoltmeter UVN BN 12001

Part one - Siemens Rel. send. 22b
Part two - The Two Transformers
Part three - The Rohde & Schwarz NGU laboratory power supply unit for vacuum tubes
Part four - The Rohde & Schwarz Vacuum Tube Meter URI BN 1050
Part five - The Rohde & Schwarz UVN BN 12001 NF Millivoltmeter
Part six - The Nordmende digital multimeter DIVO 3355 (with Nixie tubes!)

Hello,

today I'd like to introduce you the Rohde & Schwarz NF Millivoltmeter UVN BN 12001. It was produced in May 1962 and arrived at its customer in August 1962.

The specifications in short:
It can measure from 0.1mV up to 300V resp. -80 to +50dB
Frequency range: 20Hz to 20kHz balanced or 10Hz to 100kHz unbalanced

It can also be used as a measure amplifier with an amplification factor of 1000 (max 1V (0dB) rms output).
Symmetry damping depending on measuring range: > 40 ... 60dB or 4.6 ... 6.9 N (Neper)

The instrument came with the original manual, I'll add some pictures tomorrow.

But let's start with the front view:

Front view, details of the plate, right side with some jacks for connecting GND to 0V, the clamp itself, needs some cleaning, detailed view of the jacks, need some cleaning as well

Case opened:

top view, bottom view, details from the left side, bottom fixture of an electrolytic cap

Right side:

overview, shielded input transformer for the symmetrical input

Left side:

mains input with fuse, mains transformer, corroded fuse

Back side:

Party with vacuum tubes, a MP capacitor (Metal Propylene) with a date code 09/61, manufacturing date code 8th of May, 1962, precision resistor party, detailed view
The resistors have usually a tolerance of 0.5% and hide behind an Aluminium shield with the date code.

Some more detailed views of this beautiful instrument:

backside of the instrument, another MP cap in good shape, beautiful potentiometers

I did a little perfomance check with my R&S ADS arbitrary waveform generator. I've set the output to 1kHz sine and the output level to 0dB on the BN 12001. Then I increased the frequency until I got -3dB. This happened around 306kHz! Not bad! I couldn't measure the lower cut-off frequency, because the needle of the instrument only trembled.

Starting at 1kHz


-3dB cut-off at 306kHz


And here are some pictures from the manual which did come with the UVN.

28th of August, 1962 the UVN arrived at the customer, the specifications of the UVN, explanation of the origin of an interference voltage, explanation if a voltage drop occurs between the protective conductor connections between A and B, parts placement location map, map with red indexing, full scematic (hi-res, ca. 5 MByte)

I hope, you've enjoyed it.
I'll add the schematics and pictures of the specs tomorrow.

Thank you for watching!

Edit:
pictures from the manual added.

[McBryce]

   On another front... I'm having a bit of a fab & repair problem with my BBQ grill. I have a couple of the valves which have suffered impact damage; after two days of searching, it appears this valve is manufactured of weapons-grade unobtanium. 🤣   This little iron casting supports the knob shaft, which is separate from the brass casting which houses the cone valve. It would be a simple thing to whip out a replacement on a lathe...      ....until you look at the business end. This interlock is what turns the cone valve slug in the brass casting still on the grill. Replicating that turns this project exponentially more complicated. I am seriously considering this as my first actual Lost PLA 3DP project...

mnem
🙀

That's definitely not a job for PLA. I assume the area gets quite hot too?

McBryce.

Lost PLA. You make a model of PLA and use it to make a sand-casting mold, into which you then pour molten metal that vaporizes the PLA into the casting sand. Not sure how well such a small mass would work with the process, however. 

mnem
 

Ah, understood. I call that displacement molding. Did it in university, never encountered it again.

McBryce.

[Saskia]

almost done cleaning out my old condo. Unfortunately the potential buyer called in and told me he was sick and unable to come. Good thing is: there is only one IVAR left to remove. Will do so sometime next week.

My pinball care package arrived on Friday evening - containing plenty of CPU boards and other assorted PCBs.
Fixed 2 pinballs today - both BSD and Flintstones are booting and starting the game.
Now it's general overhaul and cleaning. But: those 2 are back in business.
Yay.

I do have 2 bad DMDs though. Basically these are replacement panels for the high voltage DMDs in those pinballs. I don't know what's wrong but I am not getting anything to display on the P2.5 LED panels.
Probably need to verify if the code in the STM32F4 is still good.

[Cerebus]

Ah, understood. I call that displacement molding. Did it in university, never encountered it again.

McBryce.

Also called Investment Casting in some industrial circles, a term I found very confusing at first because my mind first went to the financial usage of the word investment and it sounded to me like it was a particularly lucrative casting process.

[oz2cpu]

next week end of insane instrument auction here in Denmark
have a look
https://campenauktioner.hibid.com/catalog/348344/7277-net--flytteauktion-cobham-del-4---testudstyr--pandrup-/

[mnementh]

DADDY FAIL!!!

It appears I forgot to bring the grill back in last night after I started on my project. Sadly, hidden under that snow on the left shelf are several screws and springies which are part of those unobtanium valves. And like a dumbass, instead of just bringing it all in the garage and waiting for the snow to melt... I pawed around in the snow for those parts until my paws froze.

I am short 2 screws. 

mnem

[mansaxel]

Imaging yourself sitting as a passenger in a RHD vehicle on a German autobahn, with a notorious alcoholic at the wheel who can't even drive when he's sober. One of the greatest horrors I've ever been through.

A former colleague, Frank, used to drive a LHD car on British roads. I've been a right front seat passenger in it any times and Frank is a good, eminently trustworthy, and sober driver; it still gave me collywobbles every time we did it. Every three seconds I'd find myself trying to steer, brake or accelerate. It was fine if I was in either of the rear seats, but being in "the driving seat" when it wasn't in fact a driving seat is most, most uncomfortable. I've also been a passenger in exactly the same seat in a LHD car in Germany while negotiating the route from Ratingen to central Dusseldorf and vice-versa many times and didn't once find myself trying to brake or steer like I did in Frank's car.

I do not trust myself with driving in the UK. I'd rather take the train. Despite Dr. Beeching and more seriously, despite the flustercuck that is "deregulated railway system" (mmm, Railtrack!) there are lots of mostly working trains in the UK.

In Sweden, we went directly past the Railtrack phase and the tracks and similar infrastructure are still a government agency. On top, we've got some competition, but since rail in Sweden was built not in competetive parallel but according to a grand plan, we have much less infrastructure suited to competition. (It's not like in London where there are 3 termini adjacent to each other, offering the confused traveler some exercise by running along Euston Road trying to find the correct station....)

[mansaxel]

next week end of insane instrument auction here in Denmark
have a look
https://campenauktioner.hibid.com/catalog/348344/7277-net--flytteauktion-cobham-del-4---testudstyr--pandrup-/

For helvede mand, det var nogle fede tilbud der!

I will now immediately forget seeing so many 34401 in the same auction. Or I will go insane.

[mnementh]

Yeah... it might look funny not being mirrored like everything else... but I don't know anybody who looks at their feet while driving.

In this case, keeping the hardware UI such that everybody* develops the same muscle memory is actually a public safety concern.

mnem


*Yes, even furries.

mnem
 

[Edited to correct missing text in image.]

[Robert763]

I didn't have any trouble changing over to left hand shifting when we moved here in 2007.    I did have to take months of driving lessons before I was ready to pass the test though.  I had to unlearn years of habits that would be marked as faults on the practical.

In peace time I usually go to the UK several times per year, but in my own 'continental' car. No probs at all. I've also driven RHD vehices here in Germany without any probs. Having the wheel on the 'wrong' side never shocked me but not having it on the 'correct' side can be totally unnerving:

Imaging yourself sitting as a passenger, i.e. on the left front seat, in a RHD vehicle on a German autobahn, with a notorious alcoholic at the wheel who can't even drive when he's sober. One of the greatest horrors I've ever been through.

I used to own a Jensen Healy convertible. It was in the UK but was a Californian specification car, LHD, emissions control etc. I took a mate to a hamfest in it and for reasons unknown to me at the time, he bought a used steering wheel from one of the oudoor sellers.  So there I am happily driving llong the M4 with the top down when my passenger in the right seat suddenly sticks his hand up holding the steering wheel and waves it around.  Suddenly there are cars swerving away from us and I'm laughing so much I can't hold the car straight, adding to the "out of control" effect 
Fortunatly nobody  crashed.

[factory]

You really need to look into one of those cheap Chinese component tester. Many of the newer ones will ID Zeners up to 8-15V, and most will identify switching (1N4148, etc) diodes as well, or at least give enuf parameters you can figure that out.

I wholeheartedly recommend the ESR02; offered under many brands but always looks like this in maroon or black. If you shop carefully, you should be able to pick it up with tweezer probes for US$25-35 equiv. Flexibility and more importantly, usability (usable sockets, SMD testbed and tweezer options) put the value off the hook.

https://www.amazon.com/Transistor-Component-Capacitor-Inductance-Electric/dp/B08PDKVWLZ/

mnem

I am not sure I understand ? Other than the fancy case, it looks like the usual cheap tester everybody has ? I already have one, you can see it in the picture above... it does not have a case so I could get it cheaper, but it looks to be no more no less than your fancy one ?!

I love it  but in the case of this mountain of diodes, it would not have helped me in the slightest : I already know they are diodes, and I already know the pinout, the cathode is clearly marked... what I need to know is the actual part number on them so I can sort them, label them, and pull the datasheet. The tester can't do that...

For basic diode testing any old multimeter is fine. For serious diode testing, there's no substitute for a good power supply, a decade resistor, a good multimeter, and a pen and paper. Well, there is a curve tracer I suppose, but good ones are very expensive.

FTFY
By accident I found the TTI bench PSU (30V 2A) at work, would quite happily EOL Zener diodes when switched on, due to the output capacitance.  A decade box in series was needed to test Zeners, to avoid them ending up shorted.

The Megger used with a DVM, was good for checking high voltage Zeners too, we had some rated at 100V or was it 150V, I can't remember, the Megger did find some ordinary diodes that had been incorrectly fitted by someone else, reverse voltage was much higher than expected. 

David

Hmm, I guess some people are just cack-handed? All the power supplies I have that I'd use for this have quite low output capacitance, and in any case I'd switch on at a low voltage, probably 1V or slightly less, and turn the voltage up slowly until it goes into CC, which I'd also start with much lower than I'd expect to need to get a stable bias.

The TTI PSU at work was built into the custom made racks at the back of the bench, just out of arms reach, bit of web seaching and I suspect the PSU was the TTI TS3022S, manual shows a 100uF cap on the output.
As it was out of reach, turning the PSU up each time to test Zeners was a non-starter.

The task was to test various 6.2V Zeners, to find some that would work in a badly designed unit made by BR. About four cards in the rack had a crud dropper resistor & Zener based power supply, with two 6.2V Zeners in series, these were in parallel with the other cards.
Repairs over the years resulting in them getting very mismatched & one card taking all the load and the supply drifting out of tolerance. I found it was best to replace all of them with better matched parts, as the original Zeners were long obsolete, we had to choose a suitable modern replacement, hence all the testing.

Picture below snurched from BD139s TS3022S thread.


David

[mnementh]

*Looks at posts above*

I just love how some of our conversations evolve in here.

mnem
*toddles off to the grocery*

[Cerebus]

mnem
 

Probably slows me down as much relative to a simple typeface as it would the other way up.

[factory]

In other news: My car's wiper motor has packed up. Fault traced (thanks to a suitably rugged yellow Fluke 27 that I'm not scared to put near a circuit connected to a big lead acid battery) and unfortunately it really is a failed wiper motor, not just a 10 minute electrical fix. Looks like a combination of water ingress and  poor design of drainage points.

It looks like rain for most of the rest of the week from tomorrow so I'm off the road until I can get a replacement and fit it/get it fitted. Pah!

Per chance a Lucas motor?  Prince of wiperless? 

When did they get downgrade to Prince? 


Picture from here; https://www.gracesguide.co.uk/File:Im2013Bon-Lucas101.jpg

David

[McBryce]

Ah, understood. I call that displacement molding. Did it in university, never encountered it again.

McBryce.

Also called Investment Casting in some industrial circles, a term I found very confusing at first because my mind first went to the financial usage of the word investment and it sounded to me like it was a particularly lucrative casting process.

Ah, that's the word I was trying to remember. We actually called it displacement casting, not molding.

McBryce.

[Robert763]

The errant 100A minature current clamp turned up today when I was sorting out some fused test leads.
So that's 21 current clamps and 3 specialist current transformers.

[Saskia]

Update. One Display is back alive. Testing the other.

[Ice-Tea]

next week end of insane instrument auction here in Denmark
have a look
https://campenauktioner.hibid.com/catalog/348344/7277-net--flytteauktion-cobham-del-4---testudstyr--pandrup-/

For helvede mand, det var nogle fede tilbud der!

I will now immediately forget seeing so many 34401 in the same auction. Or I will go insane.

Oh God...

[tautech]

I just realised I made an unsupported claim about current clamps the other day. So here is proof.
I make that 23, but I do have another of the little 100A AC clamps and a LEM Analyst 1000P power analyser that has a current clamp function. Neither were to hand when I took the photos. The PR30 has not arrived yet. Oh and a couple of shunts in case I want to get invasive.

Well, I make that 20 and 2 current transformers  still an impressive array though, I can only lay claim to 3 myself.

I think you missed a CT. there are 20 clamps and 3 solid core CTs. A Tek CT2, Pearson 411 and a EEV 391.
Those 3 are pretty special items. I've not included "ordinary" non-TE solid core CTs, hall effect current sensors and shunts.

Damn fine collection Robert.
After using a TH PCB mount CT as my first current probe I skipped getting a CT2 although their specs are mighty impressive considering how old the design is and mainlined on 60 MHz P6021 and later got a 100 MHz P6022, a delightful compact passive current probe.
Of course with AC probes you can't have any significant DC component on the signal however you can check for that with the cheap modern but inferior AC/DC current probes.
To this day those old Tek designs rule.

[Saskia]

2nd display back among the living.

[tggzzz]

I didn't have any trouble changing over to left hand shifting when we moved here in 2007.    I did have to take months of driving lessons before I was ready to pass the test though.  I had to unlearn years of habits that would be marked as faults on the practical.

In peace time I usually go to the UK several times per year, but in my own 'continental' car. No probs at all. I've also driven RHD vehices here in Germany without any probs. Having the wheel on the 'wrong' side never shocked me but not having it on the 'correct' side can be totally unnerving:

Imaging yourself sitting as a passenger, i.e. on the left front seat, in a RHD vehicle on a German autobahn, with a notorious alcoholic at the wheel who can't even drive when he's sober. One of the greatest horrors I've ever been through.

I used to own a Jensen Healy convertible. It was in the UK but was a Californian specification car, LHD, emissions control etc. I took a mate to a hamfest in it and for reasons unknown to me at the time, he bought a used steering wheel from one of the oudoor sellers.  So there I am happily driving llong the M4 with the top down when my passenger in the right seat suddenly sticks his hand up holding the steering wheel and waves it around.  Suddenly there are cars swerving away from us and I'm laughing so much I can't hold the car straight, adding to the "out of control" effect 
Fortunatly nobody  crashed.

The bes I could manage in my Landie was, when driving along a single track road, to rotate the steering wheel through +-20degrees, without the car deviating.

That got the attention of oncoming drivers.

[tautech]

The bes I could manage in my Landie was, when driving along a single track road, to rotate the steering wheel through +-20degrees, without the car deviating.

That got the attention of oncoming drivers.

Yep the steering drop idlers wear out. Rebushing them is a pretty simple job.

[mansaxel]

Part five - The Rohde & Schwarz UVN BN 12001 NF Millivoltmeter

My Grundig RV55 and the [hp]400H, who nominally are suited to the same type of measurement, simply stare in awe at this. It is an order of magnitude more Richtigkeit und Ordnung. R&S simply takes things one step further.

Thanks.

[Grandpaslaboritory]

MDAS. Multi discipline acquisition syndrome

Definition:
Started by studying Electrical Engineering.  Acquired eico and heathkit test gear, then moved up and got a decent Tektronics dual beam scope (USED of course, first foray into test equipment repair, used it for years,

Got job in Pro Audio. Used previous stated test gear

Got some really good audio gear.  Needed more really good audio gear,  turned into holy grail obsession.   

Discovered talent of writing software. Got really good at it,  Need my own mini computer. Got one used - figured out that test equipment is now inadequate. Need more test equipment. Ahh the pile rises.  Got mini computer working, now we need a bigger one.  Thankfully live in Minnesota where you write software all winter so you can write off the heating of your house by powering you  racks of disk drives and mini computers.  Oops, got summer contract. Buy 2nd air conditioner for house.

Discovered woodworking,  really good, cheap woodworking equipment consists of used 3 phase stuff.  Of course, house doesn't have 3 phase. Plus equipment this large needs small factory - but it is accurate.  Here we go again....

Years pass.  Discover that old holy grail audio gear is worth a bloody fortune.  However,  need to repair old test equipment,  need more test equipment to repair test equipment.. of course, the aquired test equipment is all boat anchor style.   Needs calibration and repair.  Upgrade skills by relearning old lessons.

Buy new test equipment. Discover that even the gee wiz of new stuff just doesn't  feel like old hp and tek gear.

Repair and recalibrate old audio gear. Aquire all of the branded mates to previously owned gear.   The pile grows

Repairing friends equipment of course will require more test gear!

Aquire gear that was out of reach during my teenage years. Ahh the joys of JBL and Altec pro gear. Now we delve into the speaker rabbit hole. Then we explore early VS current solid state amps  VS  tube (valve) - of course now we need good analytical gear. What we had needed improvement, the shelves get heavier.

Need better listening environment.  Is that microphone being used to calibrate my room actually calibrated?   NEED MORE TEST GEAR

Now we are taking up cooking,  available store-bought sausage falls short.   :phew:need better meat grinder.......