Test Equipment Anonymous (TEA) group therapy thread

[tautech]

   Pokes TEA thread with OT just to see if there's anyone out there ?   Nearly record downpour event in August created a few small landslides which is just nature doing its thing but one came outta the bush and skittled some of our bush block reserve fencing !     Wouldn't be a problem except at that time of year and moment laid eyes on it knew what a tragi-mess it would turn into.     First pic shows some of the BS we had to go through with a snatch block anchored to a tree and ropes fed under the tractor onto Larry Minor's little Fiat crawler.   All that just to replace one broken strainer then some more hours to get all the wires back on it to keep stock from the reserve.     The tidy up can wait until Jan/Feb mid summer !

Uggh.    I understand viscerally what you just battled through there and... no insult intended, but better thee than me. 

mnem
three days later, you're still finding mud caked onto shit from the adventure...

You ain't kidding.
From that little write up of the escapade things got somewhat worse and me tractor slid partway over a bank....always a risk in those conditions and was left there for a week until things dried out some.
Snatch point shifted to another tree but this time Larry's little crawler couldn't get the traction required so Plan C needed to be implemented that had always been up our sleeve and was always gunna make even more mess !
Larry's 85hp 4wd tractor had no place on the hill while things were so wet but we had no Plan D so longer ropes and hand signals from afar got the thumper tractor back onto safer footing where we could happily continue making more of a mess !
Anyways it was all finished some 3 weeks back after gawd knows how many sessions between bouts of shitty weather and nearly threw a party when it was all done ! 

...But back to TEA and would you believe it... I'm helping a guy from Siglent to hack a Rigol !   

Not only believable, but actually somewhat expected, TBH. 

mnem
I can count on the fingers of one foot the number of other people that I would expect them to turn to...

Nailed it and of course the magnificent tv84 was involved......who the furk else ? 

[Specmaster]

I understand that cadmium as used for cad-plate passivation is not the same thing; I wonder if they were experimenting with CdCrO4 as a corrosion-inhibiting paint...?

I was, I hope, joking, but I wouldn't put anything beyond industrial paint manufacturers, who were using lead based paint formulations into the 1980s.

I recently found a NOS drywall expander that proudly exclaimed "Cadmium passivated" on the packaging. I left it in said packaging. Age unknown, but I guess early 70s.

Back in the 70s when there were pukka Army surplus stores in the UK, I used to get a lot of clothes, storage (steel Ammo Boxes - yayyy!) and assorted electronics from them. On the electronics everything that wasn't cadmium passivated (steel) was chromium passivated (aluminium). The military did love their toxic metal passivations.

I remember those shops as well, I used to buy clothes from the Southend on Sea one and electronics etc from the Chelmsford store. 

[med6753]

The PSU/HV board back out of the mini 212. Careful checking revealed some green copper corrosion on some patterns as well connector pins. No doubt caused by the out gassing of the old leaky Nicd's. Cleaned it up as much as possible and also reflowed many suspicious joints on the board. Did some spot check continuity. No patterns were completely destroyed.

Next step is replacement of all the HV diodes and capacitors on the left. Then a complete IPA wash.

   

[ch_scr]

Another short episode from the Fun with TEA dept:
[...]



All curves drift roughly the same direction and amount, so I'd attribute this to the 5V references, not the DMMs.
In yesterdays experiment, the green curve showed these jumps, and the blue one was more noisy - same as here, so it's the DMMs property.

These jumps in the green and yellow trace are the appropriately named "popcorn noise" from the LM399 references in the 34401A. You might consider aging a handfull of LM399 references yourself (it may be wise to get the freshly released drop-in-upgrade ADR1399) and after consideration (and depending on the result of the aging) replace at least the ref in the green 34401A and if the aging dice fall nice enough maybe the one in the yellow unit too. The lower noise should make a positive impact as well - you will have to recalibrate (or readjust to be precise) the unit(s) anyway - but that would definitely be worth the effort (given the lower noise might make those extra digits that much more worthwhile).

[Specmaster]

Just a side note.

I put an order into Digikey at 20:45 GMT last night, shipped at 05:07 GMT this morning. So it looks like Digikey at least are back to their normal speed in shipping orders.

I can't figure out if the great circle route goes over Mnem's head or Med's head, but one of you can give it a wave as it flies to me. [Checks] OK, as always with GC routes I've been fooled - it goes via Northern Quebec and just clips the north of Newfoundland.

Speaking of orders, I placed orders on eBay with 2 different sellers for 40 off GP Ultra AA and 40 off GP Ultra AAA batteries on Saturday and the order advice says Estimated delivery Thu 11 Nov - Sat 13 Nov and Estimated delivery Thu 11 Nov - Fri 12 Nov respectively but a delivery from Amazon for the self same batteries and quantities arrived yesterday.  I did look at Amazon for them but decided that as they weren't urgent, eBay would do as they were cheaper. Checked to see if the sellers have shops on Amazon and drew a blank  Guess I'll have to wait and see if they still turn up from eBay as well 

I also placed an order with CPC late Saturday, and yesterday I got an email telling me that my order had been dispatched via UPS, then I got one from UPS telling me that said delivery would be with me today between 11.15AM and 1.15PM, it arrived at 11.30AM, brilliant service.

[ch_scr]

Monitor revivement, part two:
After going from this:

to this

As you can see, the replacement capacitors have on diameter what the old capacitors had on height,
but that's what I could get and they do (barely) fit the case (Also, I don't trust physically tiny electrolytics)
Verdict: still pulsates when turning on 
Onto the (supposedly intact) power brick, that should have been the first pit-stop. In hindsight anway...
After handing the ultrasonic-welded case the old "Mikes electric stuff" treatment,
(bash on the seam with the handle of a big screwdriver until it gives)
I was greeted by this disaster:

No need to get out the DE-5000 for these two puppies 
(they had 25 of the 1000µF they started theire life with left)
Now, after also replacing them, all is well as it seems.
I left the snap-on parts of the monitor case off for now and will let it run in a bit, just to be sure...

[Cerebus]

I remember those shops as well, I used to buy clothes from the Southend on Sea one and electronics etc from the Chelmsford store. 

Most have disappeared. However, just my side of Ilford, on the junction of the Romford Road and the A116 to Wanstead there's a camping/work clothes shop that still has a fair selection of real Army surplus clothing. At least there was last time I was in the vicinity, which was pre the start of the zombie apocalypse.

[mnementh]

Currently unpacking and poking around my new 27 and the accompanying accessories while I watch Dave's teardown; the usual "getting to know you" stuff. Already I can see that even though mine is much older  (S/N 738xxx vs 909xxx) and has the yellow front label, it does have the CAT III designation on the front, contrary to Dave's statement in the vid.   



And confirmed against the parts list in the SM; 3 tants at C16/C23/C37. Good to know, as is the fact this model is not True RMS like the 27/FM, but Avg Resp only.  Dave compares it to the 28-II which supersedes it; that is an explosion-proof/intrinsically safe model.

[   

http://everyspec.com/MIL-SPECS/MIL-SPECS-MIL-T/MIL-T-28800E_5825/

If I'm reading the relevant MIL-T-28800 spec (CLASS 2, Style A designation) correctly, these are too; I would expect that being able to maintain "hull integrity" if dropped in a hazardous atmosphere is the primary reason for the uber-robust enclosure. Like Dave I was not best impressed by the 90° soldered-slot PCB riser for the fuseholders; however empirical/hearsay evidence indicates it holds up very well nonetheless.

Interesting.

mnem

[Cerebus]

Speaking of orders, I placed orders on eBay with 2 different sellers for 40 off GP Ultra AA and 40 off GP Ultra AAA batteries on Saturday and the order advice says Estimated delivery Thu 11 Nov - Sat 13 Nov and Estimated delivery Thu 11 Nov - Fri 12 Nov respectively but a delivery from Amazon for the self same batteries and quantities arrived yesterday.  I did look at Amazon for them but decided that as they weren't urgent, eBay would do as they were cheaper. Checked to see if the sellers have shops on Amazon and drew a blank  Guess I'll have to wait and see if they still turn up from eBay as well 

Someone arbitraging the pricing differences between what's 'normal' on eBay and what they can get on Amazon. Sell on eBay, buy for drop shipping on Amazon as soon as they get your order on eBay. I've had a couple of things turn up the same way (a keyboard condom for the MacBook and one of those collections of click together SMD storage boxes).

[25 CPS]

I don't care if they make us look like the fuzz; wifey and I will be toasty warm and rainproof.

Not much chance of that. What with the keto diet you won't have the ever-present doughnut in your left hand that appears to be part of the uniform. 

I do still have the concomitant coffee addiction, and I still eat a bagel every once in a while on my day off... 

mnem

Bagels aren't donuts.

Also; US theatre engineering joke:

Q: What happens when the stagehand dies?

A: The donut falls from his hand.

Q: What happens then?

A: His son picks it up.

In the TV industry, a bagel immediately means a minimum of an hour of dead air.

[mnementh]

RANDOM MODE:

Google Search: TV bagel dead air returned this.

mnem
*toddles off to find a 9V battery*

[ch_scr]

I don't care if they make us look like the fuzz; wifey and I will be toasty warm and rainproof.

Not much chance of that. What with the keto diet you won't have the ever-present doughnut in your left hand that appears to be part of the uniform. 

I do still have the concomitant coffee addiction, and I still eat a bagel every once in a while on my day off... 

mnem

Bagels aren't donuts.

Also; US theatre engineering joke:

Q: What happens when the stagehand dies?

A: The donut falls from his hand.

Q: What happens then?

A: His son picks it up.

In the TV industry, a bagel immediately means a minimum of an hour of dead air.

What I like most on the dwagons pictures is that he seems to lives by the germany saying:
"Wenn die Wurst so dick wie's Brot ist, ist's wurst wie dick's Brot ist"
"If the sausage (or feta, let's not further pick on the meat-starved) is as thick as the bread, it's no matter how thick the bread is"
Because with german, "It's sausage to me" means "I don't care". Isn't it a beautiful language 

[capt bullshot]

Izmir (woschd)

[25 CPS]

RANDOM MODE:

Google Search: TV bagel dead air returned this.

mnem
*toddles off to find a 9V battery*

I should’ve mentioned this in the original post but I forgot and since your clip brought it up, in the radio industry, a bagel immediately means dead air for the rest of the day.  If it’s a Thursday, there’s a good chance it means dead air all Friday too.

[mnementh]

LOL.... the reason for the search was I wasn't sure if you meant "A bagel break will immediately result in at least an hour of dead air" as in "when the bagels get here, jack shit happens until they're all gone" or if it was a slang term or a saying in the industry as in "Oh fuck, we had a bagel Tuesday..." which translated to normie-speak means literally "We had a hour of dead air on Tuesday". 

The minute of condensed weirdness that search returned was, IMO, in its own right worth sharing. 

mnem
eat a bagel!!!

[mnementh]

I do still have the concomitant coffee addiction, and I still eat a bagel every once in a while on my day off... 

mnem

What I like most on the dwagons pictures is that he seems to lives by the germany saying: "Wenn die Wurst so dick wie's Brot ist, ist's wurst wie dick's Brot ist"
"If the sausage (or feta, let's not further pick on the meat-starved) is as thick as the bread, it's no matter how thick the bread is"    Because with german, "It's sausage to me" means "I don't care". Isn't it a beautiful language 

If I'm going to indulge, I'm going to *~indulge~*.

mnem
"All things in moderation; including this." grand-dad (probably plagiarizing Plato or some other dead dude)

[factory]

I found this Systron Donner time code gen/reader on the Bay earlier in the week, the parcel arrived on Friday with the usual comments of "not another grey box" wrong they were as it's vomit color. 
For a change it was very well packed, wrapped in card, foam wrapped on front panel, then bubble wrap and in a large box of shredded paper. 

Quick look that evening found a shattered fuse for the HV supply and 2A fuses fitted for the mains (values marked for 110V) but has been changed to 230V in the past.
Today I found a 150mA (no 125mA in stock) fuse and two 1A fuses for the mains input and gave it a try, it seems to mostly working, but most of the tubes are very knackered and the days didn't change between 23:59:59 & 00:00:00, it has quite a noisy fan too.

<SNIP>

David

I hope the offer was a lowball...
They had listed it as used which means fully working regardless of what they put in the description. If you are not happy with it do a return through ebay or get a partial refund.

The "days" not incrementing may be because it is set as Identification number (ID) rather than days.

Maybe that post came across a little bit negative, I have no intention of returning it.
The tubes are working, but have a lot of metallic deposits on the glass, from many years of use, as a result they are quite dim, but I knew this from the sellers pictures anyway and my offer reflected that.

And you were right about the days/ID function , I noticed the reference switch was set to external, but didn't notice the days/ID switch as I'm not that familiar with this type of TE, with it set to days it works correctly.

David

[mnementh]

A'aight... the tinkerDwagon is heading out on his road trip to meet up with cylin_al; I'll not likely make the Discord today. All you freaks play nice while I'm gone.

mnem
*digs in his claws and toddles off to the Iron Rooster*

OT: Lets Do Lunch in Slightly Past Nowhere, GWN...



So the trip out of town was mostly uneventful; I stopped halfway to Slightly Past Nowhere at the Black Dog Bar & Grill for a pit stop. You know the kind of place: where the washroom has a roll of Viva on top of the paper towel dispenser and a bottle of lemon dish detergent in front of the soap dispenser...  Interesting nonetheless, as this bucolic scene has as a backdrop one of Ontario's windmill farms.



Lunch was delicious... another of the best burgers I've had, and sweet potato fries which I can't recommend enough. Also couldn't wait to eat even long enuf to snap a pic; we just dug in and talked and talked until it was time to go do the TEA part of our visit. As proof we were actually there, we decided to take some pics in front of different bikes; this time I picked the 1918 BSA. I know I'm still fattern'ell; but the last time I wore this shirt and pants was before I left Houston. Last time I tried them on was well into the lockdown; belt was 3 notches bigger and the buttons were popping like a stuffed sausage.

Still no idea my actual weight as the bathroom scale has gone AWOL since our move; either that, or my wife hid it to save my sanity. 




Here's Alan in front of the 1950 Panhead. It's a kidney-buster from the days of the Big Bopper.

After this we exchanged our TE and some token gifts, then we talked and talked and went to go 3 times and talked some more... it was good. I joked aboot being hungry; maybe we should go get some dinner... and finally headed home aboot a quarter to five.



As I wound my way through the countryside, I was treated to a glorious sunset... I snapped this shot through the windshield...




...but I had to stop and get out for this one; the light and the composition were simply delicious.




This one simply does not do justice to the depth and character of the colors at the moment; they were truly breathtaking. One of those moments that makes you feel small and naked in the face of mother nature.

Sorry aboot the big filesize on the first two; there was simply too much lost in the resized versions.   




And that leads us to the bench: This 27A/N Kit came with a undisclosed accessory: my very own TekSysyphos mug courtesy cyclin_al.

Thank you Alan; it was great to visit, and I definitely need to step up my game next meetup. My little token gifts don't hold a candle to this. 

mnem
I think I'll forego the NOT AS DESCRIBED dispute.

[Kosmic]

Another short episode from the Fun with TEA dept:
[...]



All curves drift roughly the same direction and amount, so I'd attribute this to the 5V references, not the DMMs.
In yesterdays experiment, the green curve showed these jumps, and the blue one was more noisy - same as here, so it's the DMMs property.

These jumps in the green and yellow trace are the appropriately named "popcorn noise" from the LM399 references in the 34401A. You might consider aging a handfull of LM399 references yourself (it may be wise to get the freshly released drop-in-upgrade ADR1399) and after consideration (and depending on the result of the aging) replace at least the ref in the green 34401A and if the aging dice fall nice enough maybe the one in the yellow unit too. The lower noise should make a positive impact as well - you will have to recalibrate (or readjust to be precise) the unit(s) anyway - but that would definitely be worth the effort (given the lower noise might make those extra digits that much more worthwhile).

This is not necessarily coming from the voltage reference. I had similar problem with my 34401a.



I ended up realizing it was related to the front/rear switch (problem was worst after I accidently toggled the switch). It was not making contact correctly and was probably dirty. I injected some Deoxit, exercised the switch and the problem completely disappeared.

[ch_scr]

Another short episode from the Fun with TEA dept:
[...]



All curves drift roughly the same direction and amount, so I'd attribute this to the 5V references, not the DMMs.
In yesterdays experiment, the green curve showed these jumps, and the blue one was more noisy - same as here, so it's the DMMs property.

These jumps in the green and yellow trace are the appropriately named "popcorn noise" from the LM399 references in the 34401A. You might consider aging a handfull of LM399 references yourself (it may be wise to get the freshly released drop-in-upgrade ADR1399) and after consideration (and depending on the result of the aging) replace at least the ref in the green 34401A and if the aging dice fall nice enough maybe the one in the yellow unit too. The lower noise should make a positive impact as well - you will have to recalibrate (or readjust to be precise) the unit(s) anyway - but that would definitely be worth the effort (given the lower noise might make those extra digits that much more worthwhile).

This is not necessarily coming from the voltage reference. I had similar problem with my 34401a.



I ended up realizing it was related to the front/rear switch (problem was worst after I accidently toggled the switch). It was not making contact correctly and was probably dirty. I injected some Deoxit, exercised the switch and the problem completely disappeared.

Interesting, I was not aware that a dirty switch could do that 

[capt bullshot]

Another short episode from the Fun with TEA dept:



All curves drift roughly the same direction and amount, so I'd attribute this to the 5V references, not the DMMs.
In yesterdays experiment, the green curve showed these jumps, and the blue one was more noisy - same as here, so it's the DMMs property.

This is not necessarily coming from the voltage reference. I had similar problem with my 34401a.



I ended up realizing it was related to the front/rear switch (problem was worst after I accidently toggled the switch). It was not making contact correctly and was probably dirty. I injected some Deoxit, exercised the switch and the problem completely disappeared.

This explanation looks perfectly plausible to me, as #3 (blue) had a very obvious front/rear switch issue when I received it that apparently now is completely gone - cured by nothing but excercising the switch. I'll have to check this later, as this is way more simple than ageing and replacing LM399s

[capt bullshot]

Regarding my previous post: Excercising the front / rear switch didn't help on #1 (green), but cured the smaller jumps on #2 (yellow).

So it's the LM399 popcorn noise. Anyway, I can't be bothered to run through the selection of a suitable new LM399 and readjusting the 34401. I'll keep everything as is, now knowing better their characteristics.

[BU508A]

One day I'll buy a 34401A and will replace the LM399 with an ADR1399KHZ 
They are available at analog.com for 12.28 Dollars per piece (one has to order at least 18 pieces).

[capt bullshot]

And now for something completely different: Fun with TEA

Phase noise - this is just another rabbit hole to explore

These signal generators are said to be very good in terms of phase noise.



How does one measure this? First attempt, use the spectrum analyzer (100MHz set to 0dB) - this one doesn't have a special phase noise measurement mode.



Hmm, the datasheet says -119dBc/Hz at 1kHz offset and 100MHz carrier, so there's about 20dB missing here.

So lets do it the other way, mixing the signal down to DC and measuring the demodulated phase noise. One needs a mixer for this, by some luck I've got this one around, it's a mixer and a low noise preamplifier / comparator that I built while experimenting with the DMTD clock stability measurements.



First dial in some beat note (100Hz) at the signal generators and adjust the low frequency spectrum analyzer to 0dB.



Next, set them to the same frequency (of course they have to be synchronized, I simply connected one reference input to the reference output of the other one, while the other one uses its internal reference). By offsetting one frequency and watching the DC output of the mixer, one has to set the signal generators phase to 90° (minimum DC output). This way, phase noise gets demodulated.



This is what it looks like on a scope:

 

Now, set the imput sensitivity of the 3580 to -50dB and wait for the sweep to complete:



This is 100Hz per division at 3Hz RBW, the center line equals -100dBc. So at the right hand side of the sweep, at 1kHz offset, one can see it's about -120dBc phase noise.

For reference, this is the noise floor of the mixer setup (about -130dB at 1kHz)



The data sheet shows this plot, also having a slight "peak" at about 300Hz, similar to what one can see in my measurement.

[tggzzz]

Another short episode from the Fun with TEA dept:
[...]



All curves drift roughly the same direction and amount, so I'd attribute this to the 5V references, not the DMMs.
In yesterdays experiment, the green curve showed these jumps, and the blue one was more noisy - same as here, so it's the DMMs property.

These jumps in the green and yellow trace are the appropriately named "popcorn noise" from the LM399 references in the 34401A. You might consider aging a handfull of LM399 references yourself (it may be wise to get the freshly released drop-in-upgrade ADR1399) and after consideration (and depending on the result of the aging) replace at least the ref in the green 34401A and if the aging dice fall nice enough maybe the one in the yellow unit too. The lower noise should make a positive impact as well - you will have to recalibrate (or readjust to be precise) the unit(s) anyway - but that would definitely be worth the effort (given the lower noise might make those extra digits that much more worthwhile).

It is difficult to know whether popcorn noise is in the voltage source or meter's internal reference. A good way of eliminating the possibility of the meter's reference generating noise is to measure a "noiseless" voltage source such as a Weston standard cell. (I speculate that other types of chemical cell would also have little popcorn noise).

I've used my Solarton 7081 with two Trancell zener sources and a saturated Weston standard cell. The major division is 10µV/1ppm, and 1500 reading is about 24 hours.

Trancell with 1.5ppm/15µV popcorn noise


Trancell without popcorn noise:


Saturated Weston standard cell acting as a thermometer, but without noise:



FFI: https://www.eevblog.com/forum/testgear/muirhead-kvd-and-internal-corrosion-ignore-it-or-fix-it/msg2894446/#msg2894446