Test Equipment Anonymous (TEA) group therapy thread

[bsdphk]

It was very common for coax cables to also have one or more bundles of twisted pair.

Some of the pairs were used for order-wires and remote diagnostics on repeaters in manholes, but carrier terminals were expensive and you didn't want to re-modulate too many times, so the rest of the bundle were used for traffic.

Since it was very common for long coax to pop into smaller, non-carrier, exchanges for the repeaters to be powered from their batteries, the copper pairs were then connect these minor exchanges with the next carrier terminal up or down the coax-cable, or simply as toll-lines to the neighboring exchanges.

Here is a picture of AT&T's L4 cable, from first half of 1960'ies, that is roughly the same vintage:

https://archive.org/details/bstj48-4-1065/page/n3/mode/2up

(That entire issue is about the L4 system, there is a similar issue about L3 about a decade earlier)

[Vince]

COMPONENT SORTING

OK so now that the easy stuff is done, I can start digging into the second drawer of IC's.... this time random tubes of IC's and also some new components bought in the recent years, but I of course long forgot what all that is. That will be much more fun as I have no idea what's in there, it's gonna be a surprise.

A day later... that drawer has now been processed, here is the resulting spreadsheet.

So at last some interesting stuff... not just transistors and TTL logic chips.

Problem that's torturing me is how to categorize some, many, chips that fall into 2 if not 3 different categories... I am torn. It's bordering arbitrary.

Like the AD552.. a digital potentiometer. A pot is linear stuff, analog... but it's meant to be driven by digital signal. So do I put it in the " CPU peripheral " or in the " Linear ", or " interface" categories ?

And the ULN2003 chip... it contains an array of 8 Darlingtons. So it should be in the transistor category but...  the Darlingtons are not really usable independently. All the emitters are common. Also they have a built-in freewheeling diode that all share a common anode. Also, these Darlingtons have a couple resistors around them, so as to fine tuned them because their bases are meant to be driven by logic chips. So again, do I consider it a CPU peripheral, a transistor, or a driver/interface chip... and it's like that for most chips ! 

So for some of these chips it's really a bit arbitrary 

Have only one single comparator though, and surface mount as well, a 393. So I guess I really ought to by a few different comparator types, in DIL packages...

Have some SMALL MOSFET, TO92 package, that's nice.

One single 555 timer.... need a few more for sure 

Some 4000 logic chips, good, because I had only 4 different types so far. Have a bit more now, it's more useful...

[AVGresponding]

Morning here, doing my first check of leboncoin.fr ads, and saw that :

https://www.leboncoin.fr/bricolage/2182739080.htm

Apparently posted last night at 21H14min

A cool Tektronix DMM 916, looks well featured, for only 20 Euros.
Guy says it reads current OK but all other modes are defective and the display is stuck reading : " Probes ".
Sounds like something that could be fixed... or at least well worth a shot at only 20 Euros.

Sadly like anything worth anything on this website, it's already sold, I am too late !
Not that I could have bought it anyway, but still...

So really that goes to show there are sometimes decent stuff out there... but you need to run your searches every 5 minutes day and night, never sleep, never work, never eat/cook, never go to the toilets, never go out to buy groceries... no, you need to be 24/7  on the site running your searches/keywords constantly. I can't do that, I am not a robot 

Shame you missed it, they are very nice meters, and at the price was too good to pass.

[Vince]

Yeah but no regret, weil I mean, in the sense that as I said earlier, zero money right now, even for food, as in zero money, not even 20 Euros (plus shipping as well...). So I could not have bought it anyway 

Another one will pop up later, in a year or 3.. but I will have one 

[Ice-Tea]

SR510. Works, except for the LCD which displays bogus (analog meter is stable).

[Cubdriver]

That is effing amazing, Pat. What is the sampling "gate" time on that thing? Somewhere between .75 and 2 seconds it looks? Does not appear to be exactly fixed duration, either...

I'm not sure what the sampling rate is exactly - as it seems to be functional I haven't delved too deeply into the actual operation (and don't have a correct schematic for it, either, just one for a similar unit, and it's a scan that I haven't pasted together yet).  Plan to figure it out in the future, but for now am mainly concerned with getting it back to basic functionality with the display in good nick.  Its speed may also be affected by the fact that I backed the return spring tension on the stepper relays to just about the minimum they can be set to in my initial troubleshooting in order to get them to index reliably - once the lubrication gets around and they're fully freed up, cranking that up may put a bit more spring in their steps and make them faster.

Ooooooh... you know something, Pat... they make LED dash panel bulbs in that base... 

I did at least briefly consider the LED replacements as some showed up in my searches for the replacement bulbs.

No, wait... before you go looking for the lynching rope, hear me out.

And I'd just sharpened my pitchfork, too.  Never get to have ANY fun...     

Those 328 bulbs are rated 6V; that means the unladen voltage is probably more like 7-8V. Should still be plenty for a 12V LED bulb. But here's the thing... running at considerably less current than those filaments, iffy contacts become much less of a problem, so might help in the long run.

And as a bonus... you can change the color... could have that luscious Emerald Green they're making now... or that deep pigeon's blood red like those old HP gear with the Siemens  (I think?) LED displays... or even orange to match all your nixies.   

mnem

I decided to stick with the tried-and-true filament lamps for a couple of reasons.  Mainly because I know they'll work as their ilk have been in there for literally decades and only a few have failed, so they're the simplest, known good option, still readily available and relatively inexpensive - found the four packages of ten, NOS, on eBuy for less than $30 shipped.  Secondarily because I know the displays are designed for the filament lamps, which emit light in all directions, whereas LEDs *might* be more directional - this may or may not be a factor, but is likely also very dependent on the particular LED, and because the lamps are spaced across the bottoms of the indicator plates, that could be a factor in whether they illuminate evenly or not.  Thirdly, because I haven't checked whether they're fed AC or DC and if DC what polarity, and didn't bother to measure.  Fourthly, I'd need like 42 of them to do the whole display, and it seems that those that are not from sketchy sources are at least a buck a pop.  In the end, my laziness won out and I stuck with the original part.  They were briefly in contention, but lost out to the sure thing.

-Pat

[dl6lr]

... 2400nm was unarmoured, 300nm armoured. ...

I don't think 2.4 micrometres of armour is going to make much difference. 

Sigh. The other nm in common use all around the world, i.e. not just USA.

But you knew that

So newton-metres then...?

mnem

Nautical miles?

Never mind...

[AVGresponding]

... 2400nm was unarmoured, 300nm armoured. ...

I don't think 2.4 micrometres of armour is going to make much difference. 

Sigh. The other nm in common use all around the world, i.e. not just USA.

But you knew that

So newton-metres then...?

mnem

Nautical miles?

Never mind...

Not me!

[mnementh]

... 2400nm was unarmoured, 300nm armoured. ...

I don't think 2.4 micrometres of armour is going to make much difference. 

Sigh. The other nm in common use all around the world, i.e. not just USA.

But you knew that

So newton-metres then...?

mnem

Nautical miles?

Never mind...

Not me!

numpty modulated.   

mnem
 

[capt bullshot]

... 2400nm was unarmoured, 300nm armoured. ...

I don't think 2.4 micrometres of armour is going to make much difference. 

Sigh. The other nm in common use all around the world, i.e. not just USA.

But you knew that

So newton-metres then...?

Nautical miles?

Never mind...

Not me!

numpty modulated.

near mexico

[Vince]

night marish....

[Cubdriver]

... 2400nm was unarmoured, 300nm armoured. ...

I don't think 2.4 micrometres of armour is going to make much difference. 

Sigh. The other nm in common use all around the world, i.e. not just USA.

But you knew that

So newton-metres then...?

Nautical miles?

Never mind...

Not me!

numpty modulated.

near mexico

-Pat

[AVGresponding]

* adds fuel to the fire *



https://www.ebay.co.uk/itm/125389126643





https://www.ebay.co.uk/itm/115443328055





https://www.ebay.co.uk/itm/225049334993





https://www.ebay.co.uk/itm/325245934818

[mansaxel]

Timing Interval Analyser update: I chose to put my employers money into the 5372A that bsdphk offered. Will pick it up on our way back to Sweden from our vacation targeting France,  starting this Friday.

Now downloading manuals...

[mnementh]

... 2400nm was unarmoured, 300nm armoured. ...

I don't think 2.4 micrometres of armour is going to make much difference. 

Sigh. The other nm in common use all around the world, i.e. not just USA.
But you knew that

So newton-metres then...?

Nautical miles?

Never mind...

Not me!

numpty modulated.   

near mexico

https://youtu.be/HE6EP3Z0PSU -Pat

night marish....

no manual.       

mnem
why do I smell burning pitchforks and sharpened torches...? 

[Vince]

COMPONENT SORTING


OK done digesting that large drawer.

Now found another drawer... a smaller one this time ! OK, I promise... I think... I am pretty suuuure... I really believe they aren't any more hiding anywhere now, this is the last drawer/box/bag of components that was left to process !  I guess only time will tell if that was a lie or not...

Lots of IC's again ! A whole plastic bag of brand new TO92 things as well.... guess it's all BJT...

A few cool IC's in metal cans with gold plated leads, just as I like them 

A few EPROM, love these old ceramic EPROM, they look so cool, and I am always so curious to read their contents, it's like opening a mystery box ! 
... but that will have to wait for the lab to be computerized and equipped with a chip programmer of course... so not anytime soon. The longer the wait the bigger the excitement ! 

But that will be for another day... 00H40 here and I am yawning badly.

Good night people.... 

 

[mnementh]

* adds fuel to the fire *
https://www.ebay.co.uk/itm/325245934818

That's a nice bong, but I dunno that it's 150 quid worth of nice...

mnem
 

[vk6zgo]

I doubt that cable is for sub-sea use, almost all such cables have at least one layer of steel, and much thicker envelopes.

But it is not a trivial cable either: It could transfer between two and thirty thousand simultaneous telephone conversations, depending on the route and repeater spacing.

It looks a lot like the terrestrial "coax cables" which were a big deal in Oz back in the early 1960s, before microwave links became widespread.

When the old PMG's Dept ran such a cable from Perth to Geraldton, back around '62/'63, They used the "direct burial system", & had a crew with several Cat D9s ripping a trench.

A large part of the route became  very "heavy going" for the ripper assemblies, which were lasting a lot shorter time than had been predicted.
After discussions, Cat sent an Engineer, who was "embedded" with the crew, & "burnt the midnight oil" a lot examining the damage to the rippers.
Ultimately, following his insights, Cat made some new ripper blades which did have the predicted life.

I wonder if they would go to such lengths today-----I somehow doubt it!

[tautech]

I doubt that cable is for sub-sea use, almost all such cables have at least one layer of steel, and much thicker envelopes.

But it is not a trivial cable either: It could transfer between two and thirty thousand simultaneous telephone conversations, depending on the route and repeater spacing.

It looks a lot like the terrestrial "coax cables" which were a big deal in Oz back in the early 1960s, before microwave links became widespread.

When the old PMG's Dept ran such a cable from Perth to Geraldton, back around '62/'63, They used the "direct burial system", & had a crew with several Cat D9s ripping a trench.

A large part of the route became  very "heavy going" for the ripper assemblies, which were lasting a lot shorter time than had been predicted.
After discussions, Cat sent an Engineer, who was "embedded" with the crew, & "burnt the midnight oil" a lot examining the damage to the rippers.
Ultimately, following his insights, Cat made some new ripper blades which did have the predicted life.

I wonder if they would go to such lengths today-----I somehow doubt it!

If it were for a ~400km trench(Perth to Geraldton = 373km straight line distance) you'd think so but these days an off the shelf microwave link solution would be way cheaper.....you just couldn't even get the machinery on the job for less !

[vk6zgo]

Another point is that the cable is extremely inflexible, and would be very difficult to draw between exchanges. On land they would have used single coax cables, and added more as and when extra capacity was required.

Nope! the "coax cable" runs used in Australia, which were very similar to the example in your pix, were used for very long distance  runs, like Perth to Geraldton & Melbourne to Sydney where it was "direct buried". (see my posting above).
It was never fed through normal urban cable ducts.

 Another point is that point-to-point microwave links were preferable to coax: faster/easier to install, higher capacity.

Indeed, & cheaper!
The equivalent of the East-West Microwave system between the Eastern & Western seaboards of Australia, completed in 1969, would have been prohibitively expensive to provide using coax cable.

[vk6zgo]

I doubt that cable is for sub-sea use, almost all such cables have at least one layer of steel, and much thicker envelopes.

But it is not a trivial cable either: It could transfer between two and thirty thousand simultaneous telephone conversations, depending on the route and repeater spacing.

It looks a lot like the terrestrial "coax cables" which were a big deal in Oz back in the early 1960s, before microwave links became widespread.

When the old PMG's Dept ran such a cable from Perth to Geraldton, back around '62/'63, They used the "direct burial system", & had a crew with several Cat D9s ripping a trench.

A large part of the route became  very "heavy going" for the ripper assemblies, which were lasting a lot shorter time than had been predicted.
After discussions, Cat sent an Engineer, who was "embedded" with the crew, & "burnt the midnight oil" a lot examining the damage to the rippers.
Ultimately, following his insights, Cat made some new ripper blades which did have the predicted life.

I wonder if they would go to such lengths today-----I somehow doubt it!

If it were for a ~400km trench(Perth to Geraldton = 373km straight line distance) you'd think so but these days an off the shelf microwave link solution would be way cheaper.....you just couldn't even get the machinery on the job for less !

They extended the coax to Carnarvon in the later '60s, but from there on, up to Kununurra, it was all an open wire pole route until the '80s when that run became all microwave, with a UHF spur off to Wyndham.

Nowadays, it is pretty much, "back to the future", with direct burying of optical fibre being "all the go", & microwave pretty much having disappeared, except in "niche" applications.

[tautech]

Nowadays, it is pretty much, "back to the future", with direct burying of optical fibre being "all the go", & microwave pretty much having disappeared, except in "niche" applications.

Yes we're seeing that here too yet even for the semirural location where we are, a wireless solution is faster and cheaper to rollout decent connectivity to the masses albeit not with 1GB/s connections like in urban areas.

Out our ways most of the fibre is for backhaul and it passes many potential customers gates yet they don't get an option to connect to it.
I spent a year or so discussing this with the NZ manager of new HW rollout and while he was sympathetic the pre-existing last mile copper network was to remain for the foreseeable future. 
Absolutely no vision past immediate ROI from the providers. 

We jumped ship and went wireless with a Mom&Pop ISP.

[mansaxel]

A large part of the route became  very "heavy going" for the ripper assemblies, which were lasting a lot shorter time than had been predicted. After discussions, Cat sent an Engineer, who was "embedded" with the crew, & "burnt the midnight oil" a lot examining the damage to the rippers. Ultimately, following his insights, Cat made some new ripper blades which did have the predicted life.

I wonder if they would go to such lengths today-----I somehow doubt it!

Somewhere around 2004, we had a series of PSU failures in routers in the academic part of the Internet. After discussions, and at the insistence of the PSU OEM who could not understand why their design would burn to short so frequently (IIRC a MOV decided it needed to do a "kamikaze protection action") , they sent a couple engineers to investigate. We did a bunch of site visits, had a bit of a booze-up, and did some measurements and they came back with a protection scheme they wanted to implement; an external OVP. This was done at vendor expense and all supplies stayed alive.

Since we had a lot of routers at other sites not experiencing the problem, I still suspect a highly strung batch of MOVen. But that of course was out of the question... 

[mansaxel]

Out our ways most of the fibre is for backhaul and it passes many potential customers gates yet they don't get an option to connect to it.
I spent a year or so discussing this with the NZ manager of new HW rollout and while he was sympathetic the pre-existing last mile copper network was to remain for the foreseeable future. 
Absolutely no vision past immediate ROI from the providers. 

We jumped ship and went wireless with a Mom&Pop ISP.

A long-haul network is very different from a last-mile one in so many ways. I am not surprised at all. For starters, connecting to it would require the optical equivalent of a cloverleaf interchange, an OADM. Not a practical CPE.

In the early coax / microwave years, they would not let you connect either. The pressurising equipment and the demultiplexing racks would also not be a practical CPE.

Also, all those schemes would be very bad for the long-haul signal quality.

Where opticks excel, is that they have much higher bandwidth for metro hauls than anything else, and at extremely low cost. 1,25 GBaud transceivers cost around 13€ a piece to me as an end customer. And they comfortably reach 20km over G.652 glass. But that requires a p2p link to the CO to be practical, not a drop from the long-reach fibre. (The next fool suggesting GPON will be dealt with!)

[AVGresponding]

https://www.eevblog.com/forum/dodgy-technology/the-non-linear-plasma-reactor/msg4265899/#msg4265899