Test Equipment Anonymous (TEA) group therapy thread

[tggzzz]

Is there a way to connect my logic analyzer to a computer or do stuff like I2C/SPI decoding?
I pretty much exclusively do RF and analog stuff, so I'm not well versed with logic analyzers

Probably, but I suspect you are thinking of post-processing large buffers full of captured rubbish.

If you are looking at messages, often it is better to use a tool that deals in messages, i.e. a protocol analyser. That enables you to write decent filters to ignore the boring stuff.

Scopes for analogue waveforms.
Logic analysers for digital signals.
Protocol analysers for messages.
Yes, there is overlap

[Ice-Tea]

JDSU 3GHz portable SA. I must have done something right in a previous life because the battery is not completely cooked.

Nice enough unit but seems to bog down fairly easily when it does some heavy lifting.

[TERRA Operative]

Playing with PyVISA and Python.


OMFG, is my brain NOT wired for software or what.... I don't even know what to Google for to find the answers I need....

[m k]

Ask AI.

If you try something that is hardware related and not normally available you need an interface.
That would be a library of some sort from one end, but just like other libraries from the other end.

USB connected device has an interface between its internals and USB.
No matter how known the USB side is the other side is still completely unknown.

If current pyVISA supports your doings the situation is much simpler, just ask AI.

[TERRA Operative]

Yeah, I am using PyVISA and have the communications working, but the PyVISA documentation is abysmal...., and I know next to no Python, so it'll be a steep learning curve for me to get it all working as I want.

But, it's about time I learnded my brain some Python, so I'll chip away at it.

[wkb]

I got PyVisa to work for some minimalistic scripting I am doing with my (mostly) non-SCPI -hp- equipment. The fun really starts with old equipment, as their command set is different for every instrument. E.g. two signals gens from the same era are likely to have completely different command sets. Talk to one in the wrong dialect and chances are ~95% the whole shebang just locks up.

That said, getting 50 year old equipment to listen to your HPIB commands is fun.. See the link

https://share.icloud.com/photos/00bmB4ZKEP7RgpX5SVkq2VLOQ

[tggzzz]

Yeah, I am using PyVISA and have the communications working, but the PyVISA documentation is abysmal...., and I know next to no Python, so it'll be a steep learning curve for me to get it all working as I want.

But, it's about time I learnded my brain some Python, so I'll chip away at it.

Just remember that there is a semantic (i.e. not syntactic) difference between "    " and "      ", and be very careful when you cut and paste code

[Mortymore]

Yeah, I am using PyVISA and have the communications working, but the PyVISA documentation is abysmal...., and I know next to no Python, so it'll be a steep learning curve for me to get it all working as I want.

But, it's about time I learnded my brain some Python, so I'll chip away at it.

I placed a small python code intended to collect voltage and current measurements from 2 Siglent SDM multimeters, and calculate power, here:
https://www.eevblog.com/forum/testgear/siglent-new-bench-dmm-sdm3055/msg5182602/#msg5182602

Don't know if it helps somehow.

I've ben using the free ebook "Think Python, 2nd edition": https://greenteapress.com/wp/think-python-2e/
Done some Python courses in Sololearn, and with the help of IA I've working in a bigger project that involves besides the 2 SDM, an SPD and an SDL.

[Carl_Smith]

I was told that these logic analyzers are only useful for debugging CPU systems with parallel memory interfaces.

Might be useful to have around since I'll probably find a broken piece of test equipment with a digital fault one of these days.

I remember, several decades ago, at my first real job out of college, being totally amazed by the HP logic analyzer they had, because we could connect it up to all the address and data lines of the DSP, load a program from a floppy disk onto the analyzer, and it would capture the bus and actually show the assembly code that the processor was running when it triggered.

The DSP had a 14 bit address bus, 24 bit data bus, and with some additional bus control signals, it was a lot of probe wires to connect.  And if you mixed any up the assembly code turned to nonsense.   

[Ice-Tea]

JDSU 3GHz portable SA. I must have done something right in a previous life because the battery is not completely cooked.

Nice enough unit but seems to bog down fairly easily when it does some heavy lifting.

(Attachment Link)

Oh, hello! Hadn't noticed that before but aside from some niffy SW features like a spectrogram and the like, it also features a TG! Is it Christmas already? 

[factory]

The new rectifier board for the HP 5245L has been assembled & fitted, the other board can finally return to the 5248M, diodes used were 4x 1N4006 at the top, below that 4x 1N4001 and those at the bottom are 8x 1N4004 (didn't have 1N4002). If I had looked at the later manual on PDF, I could have used 12x 1N4004 as they uprated all the lower voltage ones, all the original parts were specced at 750mA.



And I fitted the fuseholder mod for the crystal oven heater, this is to try & protect the small power transformer if the oven heater fails short circuit (no separate mains fuse provided) which is a known for failing in these. The green wire from -35V is where I added this, testing I find it draws approx 280mA when cold, going down to approx 180mA once warmed up, a 400mA quick blow fuse was fitted.



David

[shakalnokturn]

  a SOAR Yokogawa DMM, I'm sure not many people out here use one of those as their daily meter.

[m k]

Around here those can't be even sold without luck.

E,
unknown4 missing, adding shortly.

[factory]

a SOAR Yokogawa DMM, I'm sure not many people out here use one of those as their daily meter.

Well, I don't do Fluke, they are too overpriced, seen too many in the day job too, they do make good wheel chocks though. 

Around here those can't be even sold without luck.

E,
unknown4 missing, adding shortly.

The Yokogawa wasn't much, it cost £12.50 in 2018, I imagine a lot of them have probably been destroyed by Duraleak^TM by now, as they use AAAs. Also rebranded as Philips over here.
Guessing few want them now, due to it's age and it only being 4000 count. Shipping across Europe would probably exceed what I paid.

This HP 974A was acquired last year, but near the end of last year I noticed a problem, it worked OK when I got it, but had been abused by Duraleak^TM  , of course now I've moved it into the house it's not showing the leakage problem.

David

[Vince]

OK so I am trying to tidy up the lab. Many TE are in bits, have been for months or years waiting for me to finish them...

Trying to tidy up my 3 little cubical Rochar Niksee DVM.
They are all in bits, it's getting messy. They take lots of space and I risk losing bits.
Yet, I don't want to button them up 100% because I want them to be "ready" for the next diagnostics session, whenever that may be. Might be next week, next month, next year, whenever.
So I am trying to compromise.... I will slide their chassis back into their enclosure, that will save lots of space and make them easier to move around, but I will keep the face plates, rear covers and all the colour filters, together in a box.
To make things simpler, I stored and sorted the screws by type/function in little zip lock bags that I labeled : "rear cover", "front panel", "Neekc bracket", another for the feet.
Bags are common to all 3 instruments since they all use the same screws at the same place. This way less bags, simpler : I don't have to think about which meter I am working on : if I want screws for the front panel, I just grad the corresponding bag and I will get what I need...

Anyway, the reason I posted is that while doing so, i was reminded of a problem with these meters : the black metal bracket that holds and aligns all the display tubes... some tubes for some reason, are a very tight fit, and one doesn't even fit at all ! So I can't install the bracket.

I am getting bored with this issue, it's starting to irritate me...
So I investigated a bit.... turns out there are two different brands and models of the numerical tubes (the symbols tubes are all the same and fit fine).

Model F9057 made by "CSF", and a ZM1022 made by "Dario".
The service manual actually specifies ZM1022 so the ones that actually have trouble fitting ! Strange...

So I grabbed the calipers and measured stuff...
The holes in the metal bracket are 27.8mm in diameter.
One of the Dario tubes measures exactly that  ! This one does fit but it's a slight interference fit, very snug... but it eventually manages to go through the hole.
However the other Dario next to it is slightly larger at 28.0mm diameter. This one just won't fit, at all, as you would expect.

So I guess the only solution is to enlarge the hole in the bracket by 0.2mm to bring it to that tube diameter, and drill an extra 0.1mm so that it's actually a nice transition fit, neither snug nor loose... just a nice fit.
I am thinking of getting a conical drill bit for that ? A tiny pass on both sides of the hole, then a bit of sand papering to clean it up ?

All the other tubes are CSF and these are about 1.5mm smaller in diameter, so fit blind folded. Actually they are way too loose if you ask me, they can still wiggle a fair bit inside the bracket.

I don't know why the Dario are larger... however I noticed they are also slightly shorter. So maybe that adds up : given a constant amount of glass, when you form the glass, if you make the envelope slightly shorter because of poor manufacturing processes / lack of consistency, then the glass would have to go somewhere and that would translate to a larger diameter.

So I guess manufacturing tolerances for glass tubes were not super tight back in the day... but still, they could at least do some quality control to reject the "bad" tubes...
Well maybe they did, but Rochar asked to buy them anyway, to get them cheaper... and to accommodate for that, they made the holes in the metal bracket a bit larger than the CSF required, so that it would also be able to fit larger reject Dario tubes.... who knows...
Well, the end result is that I have that one particular Dario tube here that still won't fit regardless ! 

That's all from me today !

I understand there are worse problems facing humanity here and there but....

[Vince]

This HP 974A was acquired last year, but near the end of last year I noticed a problem, it worked OK when I got it, but had been abused by Duraleak^TM  , of course now I've moved it into the house it's not showing the leakage problem.

David

Ah yes, the HP looks nice....

I need to sell some of my Metrix meters and get at least one HP and one Tek DMM as well, I like them.. and that would add some variety to my collection...

One day.

[factory]

It's nice, but I did pay a bit too much for it with shipping from the US, it's had a lot of use, the captive screws for the rear cover are in poor condition too.

Re: the Rochar with random readout bulbs, the three Solartron LM1420.2 DVMs here, use three different brands, guessing they bought in bulk from whoever gave the lowest quote at the time.

David

[Vince]

Just realized there is a quick easy way for me to tell a Dario tube from a CSF, without taking things apart : looking at the tubes head on, inside the tube there is a "grill" in front of all the digits. The anode I guess ? Well this grill does not look the same on both tubes. On the CSF tubes, the grill has a square pattern to it, like chicken grill, however on the Dario tubes, that grill has a honeycomb pattern to it.
The difference between the two is quite easy to spot once you know about it.

[zepto]

The Yokogawa wasn't much, it cost £12.50 in 2018, I imagine a lot of them have probably been destroyed by Duraleak^TM by now, as they use AAAs. Also rebranded as Philips over here.
Guessing few want them now, due to it's age and it only being 4000 count. Shipping across Europe would probably exceed what I paid.

This HP 974A was acquired last year, but near the end of last year I noticed a problem, it worked OK when I got it, but had been abused by Duraleak^TM  , of course now I've moved it into the house it's not showing the leakage problem.

David

The 7544 is a great multimeter. I really like how it tells you what range it is in, and the on/off button is nice. The battery 'compartment' is of questionable design, even if it did help keep the meter compact. Iwatsu also rebadged the 7544.

[shakalnokturn]

Might be next week, next month, next year, whenever.

If you're as bad as I am on long term projects, leave yourself a little note in each instrument to remind yourself later  problems that have been solved and remaining ones.

I need to sell some of my Metrix meters and get at least one HP and one Tek DMM as well, I like them..

I remember discussing the price of the Metrix meters previously. I've almost finished letting all my extra MX53's go (until I find other cheap ones of course...) they've mostly sold for 95€ each without the protective holster.

On the way I've gained some Fluke's, Metra, Brymen, Escort, one Tek TX3, I pulled the trigger on a Tek 914 yesterday, only after did I realize it was an Escort in disguise 
Still no HP or Agilent in the collection here.

Speaking of Escort who else would suspect the Chauvin Arnoux 5289 of being an Escort/Agilent (that era of HPAK) rebrand?

[Vince]

Wow 95 Euros for an MX 53 without the rubber holster ! That used to be the price for an MX54 !

OK then, I will put a few of my MX 53 for sale I guess ! 

I will keep only the ones that in show-room / concourse condition in their original box or suit case... and of course all my MX 54 and 56 and 57Ex... these will never be put for sale !

BTW a few days ago I spotted on LBC a defective MX50 for only 9 Euros... sold instantly.. did you get it ?! 

[shakalnokturn]

All this chat about them on EEVblog over the years, more people are realising that they are good despite their age. We're pushing the prices up...

I saw the defective MX50 too, didn't catch that. There was also a MX59HD supposedly working for 50€, missed it too, a CA 5289 for 40€...

[Vince]

All this chat about them on EEVblog over the years, more people are realising that they are good despite their age. We're pushing the prices up...

Oh good !    I will sell mine only over a long period of time then... to let prices increase as far as they can go. Plus, flooding the market with half a dozen meters at once, would only drive prices down.
So just like oil producing countries, I will lower production to keep prices up ! 
I will sell only one right now, and then wait a few months for the next one, etc... 

I saw the defective MX50 too, didn't catch that. There was also a MX59HD supposedly working for 50€, missed it too, a CA 5289 for 40€...

Oh boy I too saw that 59HD last night, bummer !!   

[factory]

There was an MX20 at the Hack Green bunker sale this morning, I left it as it was £30, no holster or the extra plastic piece over the jacks.
The rain put off almost all of the outside stalls, only one this time, about half the stalls in the hanger building were military bits & pieces, the other half radio & electronic stuff. There was a HP 1740A, but I decided against buying it, as I prefer the modular 180 series.

David

[Vince]

Yeah a MX20 without the jack cover at the bottom, is not worth much... this piece is not available standalone. Same for the rubber holster.
Plus, even if it comes with the holster, it also needs to be clean, because if it's not... you will not be able to clean it ! The rubber soaks any grime and marker ink deep down and nothing can get rid of any contaminant ! Well I mean, no non-destructive means of course !

I have a lovely NOS-likeMX20 here if you want one... bought it for only 10 Euros because there is a leak somewhere, the battery drains in a matter of 60 minutes or less... but before it drains it works perfectly !
an easy fix probably, some failed decoupling cap somewhere, or if unlucky, the main ASIC is defective.... You could have it for free but as usual the shipping and customs shit is a deal breaker.
It's not work it for an MX20 as it's the lowest spec model of the ASYC range.

The MX53 is by far, byyyy faaaar, the best value for money in the ASYC range, or in the old DMM market at large dare I say, since the old Flukes are way overpriced in comparison.
If you can find a bargain, of course an MX54 or 56 is even better.

Of course if you visit France and happen to come near my neck of the woods, you would not have to pay outrageous shipping and customs !