Test Equipment Anonymous (TEA) group therapy thread

[tggzzz]

The P-3/CP-140 is based upon the Lockheed Electra commercial airliner which had limited success.

iSTR the early Electras had an unfortunate tendency to shed their wings in flight.

Not a great handicap when your competition is Viscounts!

I'd have thought the Comet 1s were a better comparison

I'm not aware of any real deficits in Viscounts, but that is absence of knowlege, not knowledge of absence. (And no, I can't even be bothered to goole it!)

Way back, I flew from Port Hedland to Perth in a Viscount---I was underwhelmed, to say the least!

My only comparison at the time was the Fokker F27, which reached cruising height in hardly any time at all, whilst the Viscount droned on interminably, before it got there.

That was just a "niggle", but I was further soured towards the aircraft, as I had a window seat, & was treated to the delights of poorly overlapped duralumin panels (you could see the gap,)
The wings seemed to flex a bit, too.

I hope they did flex, since that shows the strains are being well distributed in a controlled way. A friend of mine flew on a Soviet airliner in the late 70s, and he was worried because the wings didn't flex.

Apparently this is common with larger aircraft, but I haven't noticed it to the same extent on other planes since.

Not as much as this, I'll bet!
https://www.youtube.com/watch?t=16&v=9USXmOQdQDc

Or if you prefer a commercial airliner, here's the 777's wing test
https://www.youtube.com/watch?v=Ai2HmvAXcU0&?t=133

I was, at a fairly low level, a bit dubious about the structural integrity of the wing, but dismissed it .

Some months later, the same aircraft, on the same route shed a wing & crashed.

Disquieting Vicious rotor winds in the mountains?

An aircraft I'd been in had the main wing strut bend in flight. The passengers quickly exited, and the pilot managed to land safely.

[vk6zgo]

mnem

Arrgh,
Those old capacators were marked with the outer CAN end, but NOT because of noise pickup. It was so you could avoid having high voltage on the can (which often had fairly poor insulation) where it could be a shock / leakage (burning) hazard.
At signal and relevant noise frequencies both ends of the capacitor are a the same potential bue to the low impedance of the capacitor.

There was no "can" on old style paper capacitors of the type Carlson shows in his video.
A sandwich of foil & waxed paper was rolled up, & the lead connection to the foil that appeared on the outside was the one marked on those capacitors.
The later versions had metal deposited on the paper, & were commonly termed "metallised paper" types----these were mostly encased in some style of plastic, but a fairly large minority did have cans, & a rubber "bung" on one end!

The latter weren't that marvellous----in the late '50s/early '60s, Marconi were inordinately fond of them, & I remember changing a lot which had prematurely failed, mostly with the paper capacitors which they had supposedly supplanted.

I remember reading the same thing "Mr Carlson" was talking about, in a "hand me down" 1948 ARRL Handbook, so it's not "just something he made up".

Another point made in a later version of that tome, was that bypass capacitors were often "awkwardly" mounted across Octal, 6pin, & (large) 7 pin valve sockets, to use the earthed outer layer as a shield between grid & anode circuitry.
Rewiring to a "neater" arrangement would often cause instability in such circuits.

I take a lot of Carlson's stuff "with a grain of salt" but I think he has it right, at least as far as the old caps are concerned---modern ones, maybe not so much!

The low impedance of the capacitor seems intuitive, but capacitors of that construction have a fairly substantial inductive component, & can be relatively high impedance at higher frequencies.

In 1973/74, when we were modifying some 1959 vintage Marconi TV transmitters for PAL colour, we decided to replace a couple of 0.47uF coupling capacitors in the two Submodulators.

In both units, the originals (they were the 'metal can rubber bung' type mentioned earlier), which, though they tested OK, were in a parlous physical condition, with the bung almost falling out.
To this end, we ordered some new caps.

What we received were two new 0.47uF "Styroseal" Polystyrene caps, & lovely things they were, with a clear plastic body, where you could see the internal construction.
They also had a black line, just as the old ones did to show "which way round" to fit them.
With high hopes, we fitted them, then did a swept frequency response across the video spectrum.

At around 2MHz, the thing looked like a notch filter!!!
Hurriedly restoring the horrible original cap, that Tx was restored to service!

We re-ordered, specifying "No Styroseal", & got "bog standard" old waxed paper caps, which worked perfectly!

We must have done a good job with the mods, as the old dinosaur hung in there till the early'90s!

[cyclin_al]

On maritime patrol, I can't talk about my work much, but here is one I did 30 years ago. Not submarine but still maritime surveillance.
This had the Ferranti Seaspray 2000 search radar. Being pre GPS it had Litton VLF/Omega and inertial navigation equipment. No video either but the Agiflight 70mm film camera had a ARINC 429 datalink to the nav system and minature LEDs that imprinted the LAT/LONG and time on the film. This was important legally. We were a small company (now long gone) and apart from the design building and indstallation I flew on the aircraft for certification and operational testing.  Roaring in at 250ft towards a boat seemed to frighten the fishermen a bit 

Similarly here, I can't talk about my work of several lifetimes ago on maritime patrol.  The listening devices dropped are called "sonobouys" and there are various types.  The flight crew would decide where to drop them and then listen on what was happening below.

Oh they are terrible. Hence why the project I was working on ended up in the national press for going extremely over budget, then spiralled down the toilet, got renamed twice and then got scrapped before the end of its service life  . Everyone got paid though!

If it was renamed twice, it couldn't have been the Nimrod ASW aircraft.

I alway regarded it as remarkable that the first variant was designed to use an obsolete commercial 1950s airframe, albeit heavily modified.

They then repeated that, with a 2003 variant built on the same airframes!

Actually, while I think that a P-3 would handle nicer flying-wise, the ASW Nimrods were capable planes with a lot of endurance and a bit more speed. The systems were generally well regarded, albeit the user interfaces of a P-3C are certainly preferrable.
I had the honour?/fun? (let's keep it neutral: job) of taking some trips in one out of RAF Kinloss. Needless to say that the weather was shit. Funniest thing about Kinloss at that time was the large gathering of hippies and esoteric types living exactly under the flight path close to the runway. One could only wonder why - but they had some appealing girls among them.
Where things became REALLY crappy was when they tried to build that AEW version.

I had the misfortune of seeing the Nimrod flying.  This was at the "Ex" in Toronto, properly call the Candian National Exhibition and farm show.
Several moments later, I was watching the waves in Lake Ontario of where the Nimrod had been.
At that age, the only reason I could have missed seeing the actual crash was that I must have been distracted looking at some appealing girls...

[Zucca]

USA grid in 2022, today

21:28
power out, 7.45 VAC in the power plugs do not know which phase...

21:31
power is back but lights are weak
74.45VAC instead of 110VAC in the plugs

21:35
in the dark again. don't bother to measure....

I disconnected my entire home from the grid now.
1 First check if some lights are back on in the street
2 then measure what the grid is delivering
3 if voltages ok then flip the home back on

according to the web more than 1000 homes are in the dark.

it will be an interesting night without AC.

I simply do not trust this grid... at all.

EDIT: see attached pics... burn baby burn

 

[vk6zgo]

Some months later, the same aircraft, on the same route shed a wing & crashed.

Disquieting Vicious rotor winds in the mountains?

Nah, it was fairly flat country, just 48km out of Port Hedland but in midsummer there was the possibility of pretty bad turbulence.

Interestingly, though I remembered it as a wing falling off, the following says "broke up in flight"
There were certainly incidents of wings detaching in Viscounts used in Australia, & elsewhere, though.

https://en.wikipedia.org/wiki/List_of_accidents_and_incidents_involving_the_Vickers_Viscount

Electras seem to have had a fairly safe, if stodgy, career after the initial disasters, (they were used in Australia for years without any losses) but Viscounts seem to have continued to have them decade after decade.

In fairness to the Viscount, though, they were an earlier generation of design, & such things moved fast in the 1950s/60s.

[25 CPS]

I had the misfortune of seeing the Nimrod flying.  This was at the "Ex" in Toronto, properly call the Candian National Exhibition and farm show.
Several moments later, I was watching the waves in Lake Ontario of where the Nimrod had been.
At that age, the only reason I could have missed seeing the actual crash was that I must have been distracted looking at some appealing girls...

One of my cousins and I saw that too.

[Cubdriver]

I wound up building a lazy susan for working on things on the bench - made it from a bearing bought on Amazon and a 20 inch (~500 mm) square piece of 1/4" (6.35 mm) aluminum plate.  It makes spinning things around on the bench nearly effortless.



-Pat

[hendorog]

The hobbit in his hutch, ready to pounce...

[tautech]

The hobbit in his hutch, ready to pounce...

Yeah right 
Actually carefully studying the new PCB rulers hendorog pilfered from another stand at EMEX for us. 

[tautech]

More random stuff but certainly electronics related..... you gotta love this shirt !

[BU508A]

More random stuff but certainly electronics related..... you gotta love this shirt !

Where on earth can I get such a shirt? 

[tautech]

More random stuff but certainly electronics related..... you gotta love this shirt !

Where on earth can I get such a shirt? 

Mug the chap at EMEX that was wearing it ! 

BTW, have some RTSA images to post later that you requested.....bit tired right now. 

[BU508A]

Found this T-Shirt on AliExpress (nawts). Goes up to 5XL.
https://de.aliexpress.com/item/1005003009110719.html

[bd139]

More random stuff but certainly electronics related..... you gotta love this shirt !

Everyone I've known who wears shirts that loud has been eminently arrestable for something nefarious.


Edit: while digging through and shredding paperwork so I don't have to move with it, I discovered something I drew up in the 1990s that I never got around to building. I designed, on paper because I was broke, instead of actually doing lectures, an analogue polysynth. Wondering if I should invest in actually simulating and building it  . Controller doesn't need a Z80 board now - AVR will do the job so much cheaper and I can do away with the analogue oscillators as digital ones don't require futzing.

[tautech]

BU508A
We mucked around some setting up instrument displays as eye candy bait to pull punters in and mostly it worked very well. 

Some RTSA appetizers from phone shots.
~900 MHz amplitude and frequency sweeps from SSG3021X into hendorog's SSA3075X-R in RTSA mode in Density display...lasted ~2s

Some 3d spectrogram ones tomorrow. 

[TERRA Operative]

[Robert763]

mnem

Arrgh,
Those old capacators were marked with the outer CAN end, but NOT because of noise pickup. It was so you could avoid having high voltage on the can (which often had fairly poor insulation) where it could be a shock / leakage (burning) hazard.
At signal and relevant noise frequencies both ends of the capacitor are a the same potential bue to the low impedance of the capacitor.

There was no "can" on old style paper capacitors of the type Carlson shows in his video.
A sandwich of foil & waxed paper was rolled up, & the lead connection to the foil that appeared on the outside was the one marked on those capacitors.
The later versions had metal deposited on the paper, & were commonly termed "metallised paper" types----these were mostly encased in some style of plastic, but a fairly large minority did have cans, & a rubber "bung" on one end!

The latter weren't that marvellous----in the late '50s/early '60s, Marconi were inordinately fond of them, & I remember changing a lot which had prematurely failed, mostly with the paper capacitors which they had supposedly supplanted.

I remember reading the same thing "Mr Carlson" was talking about, in a "hand me down" 1948 ARRL Handbook, so it's not "just something he made up".

Another point made in a later version of that tome, was that bypass capacitors were often "awkwardly" mounted across Octal, 6pin, & (large) 7 pin valve sockets, to use the earthed outer layer as a shield between grid & anode circuitry.
Rewiring to a "neater" arrangement would often cause instability in such circuits.

I take a lot of Carlson's stuff "with a grain of salt" but I think he has it right, at least as far as the old caps are concerned---modern ones, maybe not so much!

The low impedance of the capacitor seems intuitive, but capacitors of that construction have a fairly substantial inductive component, & can be relatively high impedance at higher frequencies.

In 1973/74, when we were modifying some 1959 vintage Marconi TV transmitters for PAL colour, we decided to replace a couple of 0.47uF coupling capacitors in the two Submodulators.

In both units, the originals (they were the 'metal can rubber bung' type mentioned earlier), which, though they tested OK, were in a parlous physical condition, with the bung almost falling out.
To this end, we ordered some new caps.

What we received were two new 0.47uF "Styroseal" Polystyrene caps, & lovely things they were, with a clear plastic body, where you could see the internal construction.
They also had a black line, just as the old ones did to show "which way round" to fit them.
With high hopes, we fitted them, then did a swept frequency response across the video spectrum.

At around 2MHz, the thing looked like a notch filter!!!
Hurriedly restoring the horrible original cap, that Tx was restored to service!

We re-ordered, specifying "No Styroseal", & got "bog standard" old waxed paper caps, which worked perfectly!

We must have done a good job with the mods, as the old dinosaur hung in there till the early'90s!

Can, outer layer, whatever. On your video experience, ALL capacitors have a self resonance. You just found one that fell in your working bandwidth. The paper ones were probably so low Q that any resonance wasn't noticable. There is a reason whty there are hundreds of variations of X capacity Y voltage capacitor. What is imortant in one application may not be in another.
I've worked with lots of EMI EMC critical designs and have never seen a low voltage non electrolytic capacitor where the oriention was specified. In some high impedance circuits a shield at the gauard voltage was used but still no indication of alignment. This is just audiofoolery.

[Specmaster]

Some months later, the same aircraft, on the same route shed a wing & crashed.

Disquieting Vicious rotor winds in the mountains?

Nah, it was fairly flat country, just 48km out of Port Hedland but in midsummer there was the possibility of pretty bad turbulence.

Interestingly, though I remembered it as a wing falling off, the following says "broke up in flight"
There were certainly incidents of wings detaching in Viscounts used in Australia, & elsewhere, though.

https://en.wikipedia.org/wiki/List_of_accidents_and_incidents_involving_the_Vickers_Viscount

Electras seem to have had a fairly safe, if stodgy, career after the initial disasters, (they were used in Australia for years without any losses) but Viscounts seem to have continued to have them decade after decade.

In fairness to the Viscount, though, they were an earlier generation of design, & such things moved fast in the 1950s/60s.

There was only 1 incident I saw in that list that mentioned a wing failure and that was caused by an engine fire weakening the wing. There did seem to loads of incidents involving engine failures and undercarriage though.

[Vince]

Edit: while digging through and shredding paperwork so I don't have to move with it, I discovered something I drew up in the 1990s that I never got around to building. I designed, on paper because I was broke, instead of actually doing lectures, an analogue polysynth. Wondering if I should invest in actually simulating and building it  . Controller doesn't need a Z80 board now - AVR will do the job so much cheaper and I can do away with the analogue oscillators as digital ones don't require futzing.

Well yes of course you will build it... you owe it to your older (younger) self. It's part of who you  are... you will never be complete until you realize this old project.

Of course it needs to use the original Z80 of your design, or else it won't be your old project any more, but merely some modern interpretation of it, loosely inspired... but not your old project hence no point building it in the first place.  Hopefully you can find some period/vintage  Z80 assembler S/W as well, running in some MS-DOS emulator I guess. If not, OK I allow you to use a more modern Z80 assembler. That will be the only concession though ! 

Now get cracking, we are waiting for progress and regular updates. Weekly design meeting will be held on TEA one hour before Discord.

[Robert763]

The P-3/CP-140 is based upon the Lockheed Electra commercial airliner which had limited success.

iSTR the early Electras had an unfortunate tendency to shed their wings in flight.

Not a great handicap when your competition is Viscounts!

I'd have thought the Comet 1s were a better comparison

I'm not aware of any real deficits in Viscounts, but that is absence of knowlege, not knowledge of absence. (And no, I can't even be bothered to goole it!)

Way back, I flew from Port Hedland to Perth in a Viscount---I was underwhelmed, to say the least!

My only comparison at the time was the Fokker F27, which reached cruising height in hardly any time at all, whilst the Viscount droned on interminably, before it got there.

That was just a "niggle", but I was further soured towards the aircraft, as I had a window seat, & was treated to the delights of poorly overlapped duralumin panels (you could see the gap,)
The wings seemed to flex a bit, too.

I hope they did flex, since that shows the strains are being well distributed in a controlled way. A friend of mine flew on a Soviet airliner in the late 70s, and he was worried because the wings didn't flex.

Apparently this is common with larger aircraft, but I haven't noticed it to the same extent on other planes since.

Not as much as this, I'll bet!
https://www.youtube.com/watch?t=16&v=9USXmOQdQDc

Or if you prefer a commercial airliner, here's the 777's wing test
https://www.youtube.com/watch?v=Ai2HmvAXcU0&?t=133

I was, at a fairly low level, a bit dubious about the structural integrity of the wing, but dismissed it .

Some months later, the same aircraft, on the same route shed a wing & crashed.

Disquieting Vicious rotor winds in the mountains?

An aircraft I'd been in had the main wing strut bend in flight. The passengers quickly exited, and the pilot managed to land safely.

I guess this refers to MMA Flight 1750 VH-RMQ. The wing separation was caused by a fatique fracture in the lower wing spar outboard of the No.3 (inboard starboard) engine atachment. The cause of the fatigue fracture was incorrect fitting of a bush when the lower spar was replaced by ANA prevously. This was the second time the spar had been replaced. Basically five 7/16" steel bushes were supposed to pressed into the aluminium alloy spar to allow engine frame bolts to pass through. One of bushes was flared, wrongly chamfered, badly plated and partially drilled through out of alignment. They could not be sure but it was probably driven in with a tapered tool.. Basically a bodge job.  Not the fault of the Viscounts design.
Yes those wings flexed and twisted, the long engine nacelles making it even more visible.

https://www.atsb.gov.au/media/24427/196800001.pdf

P.S. A more recent bent aircraft https://assets.publishing.service.gov.uk/media/627ce6e5d3bf7f05216d7e04/Boeing_737-4Q8_G-JMCY_07-22.pdf

[Robert763]

Some months later, the same aircraft, on the same route shed a wing & crashed.

Disquieting Vicious rotor winds in the mountains?

Nah, it was fairly flat country, just 48km out of Port Hedland but in midsummer there was the possibility of pretty bad turbulence.

Interestingly, though I remembered it as a wing falling off, the following says "broke up in flight"
There were certainly incidents of wings detaching in Viscounts used in Australia, & elsewhere, though.

https://en.wikipedia.org/wiki/List_of_accidents_and_incidents_involving_the_Vickers_Viscount

Electras seem to have had a fairly safe, if stodgy, career after the initial disasters, (they were used in Australia for years without any losses) but Viscounts seem to have continued to have them decade after decade.

In fairness to the Viscount, though, they were an earlier generation of design, & such things moved fast in the 1950s/60s.

Actually wing failures in Viscounts were rare. Apart from VH-RMQ (were fatigue damage was caused by maintenence errors) They are all attributable to flying into thunderstorms or engine fires.

[mnementh]

Some months later, the same aircraft, on the same route shed a wing & crashed.

Disquieting Vicious rotor winds in the mountains?

Nah, it was fairly flat country, just 48km out of Port Hedland but in midsummer there was the possibility of pretty bad turbulence.

Interestingly, though I remembered it as a wing falling off, the following says "broke up in flight"
There were certainly incidents of wings detaching in Viscounts used in Australia, & elsewhere, though.

https://en.wikipedia.org/wiki/List_of_accidents_and_incidents_involving_the_Vickers_Viscount

Electras seem to have had a fairly safe, if stodgy, career after the initial disasters, (they were used in Australia for years without any losses) but Viscounts seem to have continued to have them decade after decade.

In fairness to the Viscount, though, they were an earlier generation of design, & such things moved fast in the 1950s/60s.

"Oh my... is the wing supposed to flap up and down like a goose...?"

"Relax, son... the wing is supposed to flex. If it didn't, it would break off."

"You mean like that...?"

*sound of shredding metal*   "AAAAAAAAAAAAHHHHHH!!!!"

I remember having this very same conversation (minus the fatal last bit) as a kid on my first commuter jet flight from PIT to ELM. I think SouthWest (the "We're not even number 2, so why even bother trying..." airline) was the carrier.    I also think this was just before some news stories about engines falling off small jets; not sure if those involved SouthWest or even the same family of craft I flew on, but I do remember it gave me a case of the "after-the-fact heebie-jeebies" at the time. 

mnem

[Neomys Sapiens]

More random stuff but certainly electronics related..... you gotta love this shirt !

Where on earth can I get such a shirt? 

I hope that you would avoid wearing depictions of such cheap commercial components!

[Neper]

For my workbench I have one of those (nawts):

Voelkner ESD Montagematte



From another ad there is this Kronhagel (Braunschweig) branded mat:



I'm finding them very useful, especially for storing small parts during repair / teardown.

They aren't exactly cheap, though.

I've been using an ordinary 'waffle pattern' rubber floor mat from the car parts supplier around the corner. Has served me well for over 20 years.

[GreyWoolfe]

I wound up building a lazy susan for working on things on the bench - made it from a bearing bought on Amazon and a 20 inch (~500 mm) square piece of 1/4" (6.35 mm) aluminum plate.  It makes spinning things around on the bench nearly effortless.



-Pat

Did the same for working on a piece of company equipment, bearing and drawer sliders from Amazon and scrap wood out of the garage.  I leave otit mounted on that side of the workbench and push it all the way in when not using it.  I still have room to work on other things.  Mine is rectangular for the device sitting on it.  It weighs 55 pounds so much easier to rotate working on the front and back than constantly picking the damn thing up and rotating it.

I have a good quality ESD mat across the entire bench but for serious cutting or for drilling holes, I have a scrap piece of 1/2 inch thick plywood about a foot square from the garage scrap bin.  I keep enough scrap lumber that Mrs GreyWoolfe encouraged me to build a bin the a corner of the garage to contain it.  She used to complain and pick on me all the time for holding on to scrap wood but after enough times of her saying, I need a piece of wood a particular size and I would go and get it, she stopped.