Test Equipment Anonymous (TEA) group therapy thread

[tautech]

What you don't want to see on your United Airlines flight 328 from Denver to Honolulu:



(It landed safely.)

You're not kidding, I bet there was a few soiled pants on that flight when it landed.

Yes of course as the public have no idea how hard pilots need train for these types of failures and as it can be seen there's no apparent damage to the airframe or control surfaces and therefore a 777 is perfectly safe to operate with just one engine however landing distances become greatly increased without the full reverse thrust that 2 engines can generate.

[factory]

A quick teardown, this radio uses a lot of those Mullard/Philips AF11x series transistors that have a bad reputation of failing with tin-whisker related shorts, despite this I haven't had any trouble with them yet.
David

Where, them mighty hard to spot ?
In the tin cans ?
 

I've added some arrows to the AF series transistors, there are four AF117 according to the circuit diagram, something doesn't add up as all the other listed types are in different packages and I see five of the AF117 size.



David

[srb1954]

What you don't want to see on your United Airlines flight 328 from Denver to Honolulu:



(It landed safely.)

You're not kidding, I bet there was a few soiled pants on that flight when it landed.

The flames are bad enough but what is more alarming is the severe vibration.

If I was looking out the window at that engine I would be thinking that it's going to fall off at any moment.

[factory]

Sort of TEA related (has a voltmeter built in), I posted a pic of my shed radio (a Danish made Sailor 16T) a while ago and someone on here was interested in seeing inside it, well I've finally had enough of the voltmeter under-reading and decided to adjust it.

A quick teardown, this radio uses a lot of those Mullard/Philips AF11x series transistors that have a bad reputation of failing with tin-whisker related shorts, despite this I haven't had any trouble with them yet.




Here is the problem I have, with an external supply set for 9V I get a reading of approx 8V of the built in meter.


Having a look at the circuit diagram they used a 10kΩ resistor in series with the meter with no provision for adjustment, it's on the power switch (arrowed).


A decade resistor was used to determine what value could be added in parallel to give a better reading, I came to the conclusion the best compromise was 83kΩ, I used a 120kΩ & 270kΩ in parallel across the original resistor.


All back together with fresh set of 6 D sized leak-tubes. 


David

I have never before come across a radio which has NW on its dial and range switch, WTF is that then?

Sorry I haven't a clue, I couldn't find anything on the NW band, maybe it's obsolete or been renamed? 

David

[tautech]

A quick teardown, this radio uses a lot of those Mullard/Philips AF11x series transistors that have a bad reputation of failing with tin-whisker related shorts, despite this I haven't had any trouble with them yet.
David

Where, them mighty hard to spot ?
In the tin cans ?
 

I've added some arrows to the AF series transistors, there are four AF117 & one AF101 according to the circuit diagram.
David

Ain't it funny how they did stuff back then !
No wonder they were hard to recognise.

[factory]

It was intended for marine use, hence they are all held in place.
I've corrected the previous post as the other transistors type use different packages, but I see five AF117 sized transistors. 

David

[tautech]

It was intended for marine use, hence they are all held in place.
David

Or they hadn't evolved from point to point construction to being able to properly route a PCB. 

[beanflying]

Re: Electronic loads: After having the parts to build one on the shelf for like 5 years I bought one of those:



https://nl.aliexpress.com/item/4000580653360.html?spm=a2g0s.12269583.0.0.35ff2d2832gPfP

CV, CC, CP and CR, 220V/20A/150W, color display, bluetooth, app. 25 eurobucks, No idea how they make money on this 

Seems there are two versions around:

I have had one of the earlier versions for a couple of years now even then there was several obvious cloned versions of the 150W Load. Unless you need to do any hardcore load testing over time one of these teamed with a logging Multimeter or two makes a lot more sense then spending a lot more for 'features'.

[mnementh]

What you don't want to see on your United Airlines flight 328 from Denver to Honolulu:



(It landed safely.)

You're not kidding, I bet there was a few soiled pants on that flight when it landed.

The flames are bad enough but what is more alarming is the severe vibration.

If I was looking out the window at that engine I would be thinking that it's going to fall off at any moment.

mnem
 

[vk6zgo]

A quick teardown, this radio uses a lot of those Mullard/Philips AF11x series transistors that have a bad reputation of failing with tin-whisker related shorts, despite this I haven't had any trouble with them yet.
David

Where, them mighty hard to spot ?
In the tin cans ?
 

I've added some arrows to the AF series transistors, there are four AF117 & one AF101 according to the circuit diagram.
David

Ain't it funny how they did stuff back then !
No wonder they were hard to recognise.

Easy for those of us who were around, Sonny!     

[mnementh]

Re: Electronic loads: After having the parts to build one on the shelf for like 5 years I bought one of those:



https://nl.aliexpress.com/item/4000580653360.html?spm=a2g0s.12269583.0.0.35ff2d2832gPfP

CV, CC, CP and CR, 220V/20A/150W, color display, bluetooth, app. 25 eurobucks, No idea how they make money on this 

Seems there are two versions around:

I have had one of the earlier versions for a couple of years now even then there was several obvious cloned versions of the 150W Load. Unless you need to do any hardcore load testing over time one of these teamed with a logging Multimeter or two makes a lot more sense then spending a lot more for 'features'.

https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/msg3473896/#msg3473896

I took a long look this morning at bang-em-good's current lineup; they've def upped their game in that corner since the last time I searched electronic loads with them. Lots of links in my post above.

mnem
*couch-tuber time widda boi*

[vk6zgo]

It was intended for marine use, hence they are all held in place.
I've corrected the previous post as the other transistors type use different packages, but I see five AF117 sized transistors. 

David

Philips did that with their early transistor portable radios, too.

[tggzzz]

What you don't want to see on your United Airlines flight 328 from Denver to Honolulu:
(It landed safely.)

Worse would be from Honolulu to Denver

The simple matter-of-fact captain's report that really caught my imagination was a 1989 incident where an engine detonated. To me it is much more terrifying and a much greater fear of airmanship than Sullenberger's landing in the Hudson - when other pilots reproduced it in simulators, they all failed and would have dieduuu.

The captain gave a leture at NASA Ames Research Center as a form of therapy, and I first saw this transcript on usenet: https://yarchive.net/air/airliners/dc10_sioux_city.html

They made it into a not very good film, which completely failed to get over the rather important small details. One that stuck in my mind is that afterwards in the hospital the captain completely failed to recognise the third pilot who came into the cabin to help control the aircraft - because he never looked at his face while they were flying.

[tautech]

A quick teardown, this radio uses a lot of those Mullard/Philips AF11x series transistors that have a bad reputation of failing with tin-whisker related shorts, despite this I haven't had any trouble with them yet.
David

Where, them mighty hard to spot ?
In the tin cans ?
 

I've added some arrows to the AF series transistors, there are four AF117 & one AF101 according to the circuit diagram.
David

Ain't it funny how they did stuff back then !
No wonder they were hard to recognise.

Easy for those of us who were around, Sonny!     

back at ya ! 
So as you were around back then how long was it before you recognised long leads on those transistors for example might be counterproductive to low noise sensitivity ? 

[Neomys Sapiens]

I have two electronic loads: A Zentro ELA 40/40D (40 V/ 40 A, 200 W) and a TET 60 V/ 100 A. Alas the latter is dead, and there's absolutely nothing to find about it. I opened it once and and looked for something to measure, like a supply voltage, when suddenly both supersonic wind tunnels sprang into action, startling me to death. Still, it didn't work. And even after looking for half an hour, I hadn't find a way to disassemble it. My relationship with mechanical engineers is a bit strained.

Ein MASCHINENBAUER ist ein Landwirt nach dem Erwerb des ersten selbstfahrenden Arbeitsgeraets!

[SilverSolder]

[...]
The flames are bad enough but what is more alarming is the severe vibration.

If I was looking out the window at that engine I would be thinking that it's going to fall off at any moment.

The vibrations are likely why everything fell apart in the first place.  Wonder if there is an "engine vibration monitor" in the cockpit?

[vk6zgo]

What you don't want to see on your United Airlines flight 328 from Denver to Honolulu:



(It landed safely.)

Much nicer to see something like that just after takeoff, instead of in mid-Pacific!

On the subject of looking out the window & being a bit disturbed, I recall, back in 1968, looking out the window at the wing of a Viscount & being a bit worried that the riveted panels seemed to have largish gaps, rather than sitting flush.

I put it down to a jaundiced view of the Viscount, compared to the Fokker F27 I had been travelling in previously, which had a short take off distance & a fairly spectacular climb rate for an airliner.

With the much bigger & older beast, I was surprised by how long it took to reach operating height.
About when the flight attendants were normally handing out "munchies" & pouring coffee in the F27,the Viscount was still groaning & moaning to gain height.

With nothing else to do, I returned to gazing out the window, & apart from the rough looking constuction of the panels, compared to the Fokker, noted a large amount of wing flex.

"Don't be sillly!", I told myself, it just looks different, not necessarily worse!

Sadly, a couple of months later, on the same route, that aircraft "fell out of the sky"--------& yes, a wing fell off!

[SilverSolder]

What you don't want to see on your United Airlines flight 328 from Denver to Honolulu:



(It landed safely.)

Much nicer to see something like that just after takeoff, instead of in mid-Pacific!

On the subject of looking out the window & being a bit disturbed, I recall, back in 1968, looking out the window at the wing of a Viscount & being a bit worried that the riveted panels seemed to have largish gaps, rather than sitting flush.

I put it down to a jaundiced view of the Viscount, compared to the Fokker F27 I had been travelling in previously, which had a short take off distance & a fairly spectacular climb rate for an airliner.

With the much bigger & older beast, I was surprised by how long it took to reach operating height.
About when the flight attendants were normally handing out "munchies" & pouring coffee in the F27,the Viscount was still groaning & moaning to gain height.

With nothing else to do, I returned to gazing out the window, & apart from the rough looking constuction of the panels, compared to the Fokker, noted a large amount of wing flex.

"Don't be sillly!", I told myself, it just looks different, not necessarily worse!

Sadly, a couple of months later, on the same route, that aircraft "fell out of the sky"--------& yes, a wing fell off!

Wow, that no mechanic caught the signs when the rivets are literally popping out...

I imagine some techies are sweating now, about answering questions about an engine vibrating itself to death after they just gave it the All Clear...

[mnementh]

But deregulation has nothing to do with it at all. 

mnem
Nothin' to see here folks; move along, move along...

[25 CPS]

You have now, my old Beckman 310 has a 22MΩ input impedance for Vdc (warning 2, 20 & 200 Kelvin Ω ranges may trigger  );


The newer Wavetek (took over Beckman) HD160B isn't 22MΩ, but still has the 1500Vdc range as the older meters do.

I agree with hooking the probe on before power-up, something Shango066 does on many TV resurrections to monitor the HT voltage (a common problem area with ancient TV's) while bringing them up with lamp-limiter and/or variac and while capacitors are reforming.

David

Cool.  I figured there had to be at least a few meters out there with 22 M\$\Omega\$ input impedances out there otherwise nobody would've bothered making accessories like that probe that depended on that characteristic.  It's just not one I've encountered before.  Everything I've run across has either been 10 M\$\Omega\$ or the really, really high impedances on some of the ranges that HP/Agilent and similar bench meters have.

Woah, I completely missed that part. I found some specs online and they were talking 10M. I guess it was the model HV321-10. 22M is weird. I don't think I even seen a meter with a 22M input impedance.

I double checked my meters and I'm SOL so I'm going to let it go.  I wonder if that probe's eventually going to end up with someone making a quick decision to buy it based on price but then finds out the hard way once it arrives and they try to use it that the readings are all off if their meter doesn't happen to be correct for it?  I just have the sneaking suspicion that someone out there's going to end up disappointed.

[capt bullshot]

Re: Electronic loads: After having the parts to build one on the shelf for like 5 years I bought one of those:



CV, CC, CP and CR, 220V/20A/150W, color display, bluetooth, app. 25 eurobucks, No idea how they make money on this 

Looks like one of these that have only one transistor to dissipate the load, and their spec equals the transistors spec @25°C. Doesn't take much effort to toast them.
The KP184 at least has 6 transistors to dissipate 400W, so I'd expect it to stand longer ...

[capt bullshot]

Would someone like to explain to a thicko (me) what is the actual difference between a 75 and 50 BNC and would I tell them apart?

Easy with a new toy like capt bullshot has got....a VNA ! 

To spot that difference, one must have $$$ cal kit and cables, too ...

[tautech]

Would someone like to explain to a thicko (me) what is the actual difference between a 75 and 50 BNC and would I tell them apart?

Easy with a new toy like capt bullshot has got....a VNA ! 

To spot that difference, one must have $$$ cal kit and cables, too ...

Only for accurate measurement as you will still see the differences. 

[SilverSolder]

Would someone like to explain to a thicko (me) what is the actual difference between a 75 and 50 BNC and would I tell them apart?

Easy with a new toy like capt bullshot has got....a VNA ! 

To spot that difference, one must have $$$ cal kit and cables, too ...

Only for accurate measurement as you will still see the differences. 

What does the "distortion" actually look like, if it is only the connector that is 75 ohm and the rest of the circuit is 50 ohm?  Does it reflect energy at higher frequencies, or something like that?

[tautech]

Larry Major (older larrikin son in Perth) sent a pic of his spa pool pump motor that kept eating impellers as it occasionally ran in reverse rotation ........pretty obvious why.