Test Equipment Anonymous (TEA) group therapy thread

[med6753]

My objectives for 2022:

My entire adult life I was unfamiliar with hospitals. Then in 2021 I was in the hospital at least 5 times on an inpatient or outpatient basis. Objective for 2022 is to never be in another one just as in the past.

Get repair cue cleaned up. It's not large but it is complex. 

[capt bullshot]

Still, my scope probes have very thin and flexible cable, like the transparent stuff but black... so I guess this means it must be yet another RG-XYZ norm again ? Which one ?

Must be someone who knows on here... don't be shy... help me buy nice cables so I don't waste my money on crappy super stiff cables 

The search continues...

Scope probe cables are a totally different beast, as they have a very thin inner conductor. This conductor is resistor wire to provide a deliberate amount of damping.

What you're (most probably) looking for: RG174

[Robert763]

The "RG" series of cable designations are obsolete military specifications. RG-58 is 50 ohm nominal impedance. The C/U variant  has a stranded center conductor making it more flexible but slightly higher loss than the solid conductor variant.
RG58C/U is a good choice for general purpose coaxial test leads up to VHF frequency.
Note that very few of the cheap cables are made to the full specification. in particular the amount of copper in the screen is much lower. Unfortunately you can't tell until you cut the cable. Unless the cable also has a known manufacturer's (e.g Belden) part number you don't know what it is. You generally get what you pay for.

Thanks Robert.

Just found this table from the IDC, that says the letter suffix determines also the impedance...  with 'C' suffix being the only one that's actually 50ohms. Others are 52 or 53.5.

But since you say this is all obsolete and all RG58 sold these days is 50 ohms, that makes it easier...

So 'C' suffix seems the best choice then, at least to begin with... I have zero coax cables here, would you believe it, other than a crappy 75ohms RG59 cable I bought by mistake thinking it was 50ohms... old guy at the local electronics shop who sold it to me 4 years ago, swore it was 50 ohms, yeah....   

So I am looking at getting a few decent coax cables and various adapters to get me started in the lab. So many scopes and counters here, and not even cables and adapters to actually use them, how ironic 

OK so some RG58 C suffix should have me sorted, thanks, will go shopping on Farnell's site... will get something decent. They sell TE Connectivity or Amphenol mostly, should be decent hopefully.

00.02 here, 2022 here I come...

The current replacement for all the RG58 cables in US military standards is M17/28 which is a "slash sheet" to MIL-DTL-17 (formerly MIL-C-17). It is sometimes quoted as M17/20-RG058
This is 50 R stranded core
see https://quicksearch.dla.mil/Transient/0A40614FE389453F98AC27E3939C4DA1.pdf
for the official specification.

[capt bullshot]

Happy new year to one and all.

My goal is to throw out a lot of stuff. Too many things I haven't touched for years.

That never works for me

[Robert763]

<SNIP>

Still, my scope probes have very thin and flexible cable, like the transparent stuff but black... so I guess this means it must be yet another RG-XYZ norm again ? Which one ?

Must be someone who knows on here... don't be shy... help me buy nice cables so I don't waste my money on crappy super stiff cables 

The search continues...

Scope probe cables are NOT coax. They are special cable. Most have a resistive center conductor. The cable is a critical part of the probe division and compensation circuit.

[Neper]

Happy new year to one and all.

My goal is to throw out a lot of stuff. Too many things I haven't touched for years.

That never works for me

Same here, but isn't that the very essence of New Year's resolutions? 

[wolfy007]

My last save from ewaste bin at work for 2021;

I'm green with envy. I really could use that at times.

I did get two Tunable Laser Sources if you need one of those.

[Specmaster]

I'm going with the through type of plugs to ensure that the correct cables are in the right positions before crimping as I've never really learnt the knack of getting the wires into the correct slots on the standard plugs. Does anyone else have the same problem?

Used to until I watched how our ISP buddy does it.
Overstrip and manipulate the strands into their correct positions and flex and tweak them between thumb and forefinger until they are all nice and straight and behaving themselves.
Then snip to correct length and offer up the RJ45 plug which should initially slide on with little effort however getting them all the ways home might take a bit of wiggling and shoving.

Did a couple the other day after not having done any for years and they worked out mint. 

I've watched many people do it on video before and I have managed to do it once or twice but only after ruining many plugs  maybe its because I have such big hands or something. When I was working, we used 6 core flat cable for our lighting control networking and never had any trouble terminating those, but make them into a circular cable and I struggle 

I can and have used both types but I do prefer the through type, my Amblyopia and astigmatisms are enough that I have to use my Optivisor to make patch cables.  Many years ago, I used to make patch cords for a part time gig I had so I got used to using the regular connectors.  Age has forced the use of magnification and the use of through connectors eliminates the fuss I have of trying to get the length right, I start long and keep lopping of a a little at a time until it fits right.  Being far sighted and having an issue with depth perception also doesn't help using the regular connectors.  I have large hands also so I don't think that has anything to do with it.  I do overstrip and manipulate the strands into their correct positions and flex and tweak them between thumb and forefinger regardless of the type of connector as I find the cable feeds in easier regardless of the connector used.

I only mentioned the large hands as a possible factor because you have to strip the cable to a specified length and then when tweaking the strands between thumb and forefinger, you have less of the strands protruding in order to push into the respective channel within the plug shell. The size of your fingers and thumbs should be the only variable in the equation and before when I used the standard shells, I was quite a bit lighter than I am now.

[Specmaster]

Oi... spinning rust is sooooo slow... 

Currently updating my old gaming rig (Athlon FX-8350 8-Core 4.0GHz/16GB DDR3-667/XFX RX580 Black Edition) which has been in the trailer unused for 2 years to the latest Win10, so I can have something to peek in here on while I let my son use my i7 laptop on his new 27in/1mS/IPS eSports monitor for his gaming sessions.

Well, and cuz I could. 

mnem
*cellar-dweller dwagon again*

Don't be too hard on it, it is after all having to do 2 years of updates.

[AVGresponding]

Quick update on the faulty RF gen from ebay.

Seller responded quite quickly, and asked for video of the problem sent to an external (from ebay) email, along with a repeat of the description of the problem and the order number.

Yeah, nah mate. Not happening. Everything goes through ebay, so he can have a couple of pics, no video. There's no way I'm giving them any of my email accounts so they can spam me with phishing emails, and I can't be arsed to make a disposable one.
They are clearly just trying to duck responsibility, so it'll probably end up with ebay refunding me and the seller going on my blacklist. Naturally I'll post their seller id here too.

[Neper]

Seller responded quite quickly, and asked for video of the problem sent to an external (from ebay) email, along with a repeat of the description of the problem and the order number.

...the usual tactics of letting people jump through a succession of hoops in the hope that they'll eventually give up. Have they already offered you a refund of something like 1 percent of the auction price?

[Specmaster]

<snip>
And to not start any more international incidents. 

mnem
*heeds Hypnos' siren call*

What is the dwagon loosing his firepower now, mellowing in his old age then eh?

[Specmaster]

My objectives for 2022:

My entire adult life I was unfamiliar with hospitals. Then in 2021 I was in the hospital at least 5 times on an inpatient or outpatient basis. Objective for 2022 is to never be in another one just as in the past.

Get repair cue cleaned up. It's not large but it is complex. 

Thats a good objective, does that mean that your not after anymore boat anchors then?

[BU508A]

My objectives for 2022:

My entire adult life I was unfamiliar with hospitals. Then in 2021 I was in the hospital at least 5 times on an inpatient or outpatient basis. Objective for 2022 is to never be in another one just as in the past.

Get repair cue cleaned up. It's not large but it is complex. 

Thats a good objective, does that mean that your not after anymore boat anchors then?

I think, this depends of what kind the boat anchor is. 

[med6753]

My objectives for 2022:

My entire adult life I was unfamiliar with hospitals. Then in 2021 I was in the hospital at least 5 times on an inpatient or outpatient basis. Objective for 2022 is to never be in another one just as in the past.

Get repair cue cleaned up. It's not large but it is complex. 

Thats a good objective, does that mean that your not after anymore boat anchors then?

I think, this depends of what kind the boat anchor is. 

I never said a word about additional acquisitions, on purpose. 

[AVGresponding]

Seller responded quite quickly, and asked for video of the problem sent to an external (from ebay) email, along with a repeat of the description of the problem and the order number.

...the usual tactics of letting people jump through a succession of hoops in the hope that they'll eventually give up. Have they already offered you a refund of something like 1 percent of the auction price?

They haven't offered anything as yet. I'm certainly not paying anything for this one, they can send me a return label. It may or may not be fixable, in point of fact the PLL lock LED actually comes on properly now, but the performance otherwise is unchanged.

The fact they asked me to communicate outside ebay undermines their case massively; ebay will frown deeply when they see that and likely come down 100% on my side regardless of anything else.


Oh, here are the pics I sent. You can see the frequency is miles off, and the waveform at the lower frequency is horrible.

[BU508A]

Differences in American English and British English explained by ... a German lady:



  

[ch_scr]

Seller responded quite quickly, and asked for video of the problem sent to an external (from ebay) email, along with a repeat of the description of the problem and the order number.

...the usual tactics of letting people jump through a succession of hoops in the hope that they'll eventually give up. Have they already offered you a refund of something like 1 percent of the auction price?

They haven't offered anything as yet. I'm certainly not paying anything for this one, they can send me a return label. It may or may not be fixable, in point of fact the PLL lock LED actually comes on properly now, but the performance otherwise is unchanged.

The fact they asked me to communicate outside ebay undermines their case massively; ebay will frown deeply when they see that and likely come down 100% on my side regardless of anything else.


Oh, here are the pics I sent. You can see the frequency is miles off, and the waveform at the lower frequency is horrible.

I agree on the assesment that the seller would like to dodge responsibility, but also I can see that they want "good proof" the unit is actually faulty (they also have likely been scammed by dishonest buyers). One might argue they want video because "flickering lock-LED & jumping frequency" is really hard to convey in a picture - email is most likely the "most easy" way for both partys to get the video from one to the other. Also, I might add, your pictures of it working on some specific frequencies might be interpreted by a suspicious seller as "unit is working, buyer is trying to get it for free".
Also, the non-sinusoidal waveforms are expected! I think the PLL IC operates in "frequency divider mode" up to 2.2GHz, and that divider output is more or less a square wave. I think I mentioned that but worded it less directly before. Also also I might add that with such high harmonic content (as in a square-ish wave) even at "low" frequencies (say 50MHz) there might be a lot of energy up to 500MHz in those fast edges - which means you want to pay close attention to terminate your transmission lines, before trusting / judging what you see on the scope. That cable might be "too short for funny effects" at 50MHz but surely not at 500... As in have a scope with 50 input mode (best case) or use a BNC through-termination or at least a BNC-tee with a terminator. You can easily see the effect (IF there is one ) in the latter case when plugging / unplugging the terminator 
Good luck! 

[factory]

I'm curious, what is the search term needed to find those solder on PCB edge pins? We had them on stuff at work and I never found out what they were, in the 15-ish years I worked in the electronics lab.


David

Damn, I found these the other day and thought "I'll have to remember what those are called" and promptly forgot. However like all people good at simulating being clever, I know where to look it up. Hold on ...

"Contacts - leadframe", leastways that's what Digikey has them catalogued.

Weird isn't it? I'm not smart enough to remember what I found out, but I am smart enough to remember where I found it out.

Here's the Digikey link for the exact part, that should get you started. It took a bit for me to find them and figure out what they were called too.

https://www.digikey.com/en/products/detail/te-connectivity-amp-connectors/1544210-2/4731536

Thanks to both of you for for the info on those leadframe connectors, should probably add some to my next order, now I know what to buy. 

P.S. the mention of Digikey reminded me I did find a source of 9312DC multiplexer ICs, similar to those that are used in the 5340A, unfortunately the third party seller on Digikey will only sell them in quantities of 167 or more. 
Anyway the 74151 (different pinout) is on the way.

P.P.S. Maybe 2022 will be the year I finally figure one of those CAD programs out & get some boards made.

David

[GreyWoolfe]

Oi... spinning rust is sooooo slow... 

Currently updating my old gaming rig (Athlon FX-8350 8-Core 4.0GHz/16GB DDR3-667/XFX RX580 Black Edition) which has been in the trailer unused for 2 years to the latest Win10, so I can have something to peek in here on while I let my son use my i7 laptop on his new 27in/1mS/IPS eSports monitor for his gaming sessions.

Well, and cuz I could. 

mnem
*cellar-dweller dwagon again*

Don't be too hard on it, it is after all having to do 2 years of updates.

Windows updates has reminded me that my main computer is not compatible with Win11.  I have decided that the fight to get around TPM is not worth it.  For the past couple of weeks I have been playing with Linux Mint Cinnamon 20.2 on an old laptop and desktop.  I quite like it and I like the way it handles updates.  I have a long way to go to learn command line structure but that's OK.  Testing Mint on my Lenovo Thinkcenter M93P, core I7 4990, 32 Gb ram and 512 Gb SSD shows no hardware compatibility issues.  I just have one thing to figure out migrating Thunderbird with my 3 email accounts to another computer so I can do the upgrade and move email back over and then I will be windows free.  Unfortunately, Mrs. GreyWoolfe's computer must remain a Windows computer because she does occasionally do work from home and it took an act of God and 7 Hail Marys to get their idiot of a sysadmin to get a VPN and RDP session set up so she can log into her work computer remotely.  She doesn't want to do that dance again and insists I leave her computer alone.  We will see what happens when Win10 hits EOL and /or her computer slips its mortal coil.

Also I want to wish all you reprobates here a happy and healthy New Year.  This year has been full of challenges for me and I am hoping and praying 2022 will be better and not 2020 (part)2.

[Kosmic]

Seller responded quite quickly, and asked for video of the problem sent to an external (from ebay) email, along with a repeat of the description of the problem and the order number.

...the usual tactics of letting people jump through a succession of hoops in the hope that they'll eventually give up. Have they already offered you a refund of something like 1 percent of the auction price?

They haven't offered anything as yet. I'm certainly not paying anything for this one, they can send me a return label. It may or may not be fixable, in point of fact the PLL lock LED actually comes on properly now, but the performance otherwise is unchanged.

The fact they asked me to communicate outside ebay undermines their case massively; ebay will frown deeply when they see that and likely come down 100% on my side regardless of anything else.


Oh, here are the pics I sent. You can see the frequency is miles off, and the waveform at the lower frequency is horrible.

I agree on the assesment that the seller would like to dodge responsibility, but also I can see that they want "good proof" the unit is actually faulty (they also have likely been scammed by dishonest buyers). One might argue they want video because "flickering lock-LED & jumping frequency" is really hard to convey in a picture - email is most likely the "most easy" way for both partys to get the video from one to the other. Also, I might add, your pictures of it working on some specific frequencies might be interpreted by a suspicious seller as "unit is working, buyer is trying to get it for free".
Also, the non-sinusoidal waveforms are expected! I think the PLL IC operates in "frequency divider mode" up to 2.2GHz, and that divider output is more or less a square wave. I think I mentioned that but worded it less directly before. Also also I might add that with such high harmonic content (as in a square-ish wave) even at "low" frequencies (say 50MHz) there might be a lot of energy up to 500MHz in those fast edges - which means you want to pay close attention to terminate your transmission lines, before trusting / judging what you see on the scope. That cable might be "too short for funny effects" at 50MHz but surely not at 500... As in have a scope with 50 input mode (best case) or use a BNC through-termination or at least a BNC-tee with a terminator. You can easily see the effect (IF there is one ) in the latter case when plugging / unplugging the terminator 
Good luck! 

If its based on the ADF4351, you can expect a sinewave between 2200 - 4400MHz and a squarewave between 35 - 2200MHz (going through the divider).

From the specsheet:

The ADF4351 has an integrated voltage controlled oscillator (VCO)
with a fundamental output frequency ranging from 2200 MHz to
4400 MHz. In addition, divide-by-1/-2/-4/-8/-16/-32/-64 circuits
allow the user to generate RF output frequencies as low as 35 MHz.

[Specmaster]

Seller responded quite quickly, and asked for video of the problem sent to an external (from ebay) email, along with a repeat of the description of the problem and the order number.

...the usual tactics of letting people jump through a succession of hoops in the hope that they'll eventually give up. Have they already offered you a refund of something like 1 percent of the auction price?

They haven't offered anything as yet. I'm certainly not paying anything for this one, they can send me a return label. It may or may not be fixable, in point of fact the PLL lock LED actually comes on properly now, but the performance otherwise is unchanged.

The fact they asked me to communicate outside ebay undermines their case massively; ebay will frown deeply when they see that and likely come down 100% on my side regardless of anything else.


Oh, here are the pics I sent. You can see the frequency is miles off, and the waveform at the lower frequency is horrible.

, 35MHz shows up as 71.34MHz and 110MHz becomes 142.31MHz, the thing isn't even anywhere near linear making a prediction of the true frequency impossible. Press ahead with a claim through eBay, as you rightly said, trying to resolve outside of their system is a no no and could even carry repercussions for you as well.

[Andrew_Debbie]

Dana 5100 DMM update.
 
I submitted the board for fabrication.   Cost is about $95 for five with all the SMT parts assembled.    That includes taxes, customs clearance and FedEx IP. 

I had to make a last minute changes because parts went out of stock during the design process.      I've got the through hole parts here.     Will it work?  I have no idea.

[med6753]

Differences in American English and British English explained by ... a German lady:



  

That's fine with me because I can understand her (and most other Germans who speak English) better than the Brits. 

[factory]

Seller responded quite quickly, and asked for video of the problem sent to an external (from ebay) email, along with a repeat of the description of the problem and the order number.

...the usual tactics of letting people jump through a succession of hoops in the hope that they'll eventually give up. Have they already offered you a refund of something like 1 percent of the auction price?

They haven't offered anything as yet. I'm certainly not paying anything for this one, they can send me a return label. It may or may not be fixable, in point of fact the PLL lock LED actually comes on properly now, but the performance otherwise is unchanged.

The fact they asked me to communicate outside ebay undermines their case massively; ebay will frown deeply when they see that and likely come down 100% on my side regardless of anything else.


Oh, here are the pics I sent. You can see the frequency is miles off, and the waveform at the lower frequency is horrible.

, 35MHz shows up as 71.34MHz and 110MHz becomes 142.31MHz, the thing isn't even anywhere near linear making a prediction of the true frequency impossible. Press ahead with a claim through eBay, as you rightly said, trying to resolve outside of their system is a no no and could even carry repercussions for you as well.

And why the hell does the display show mHz instead of MHz? clearly a PoS. 


David