Test Equipment Anonymous (TEA) group therapy thread

[beanflying]

Sounds more promising for low speed DC fans  Still waiting on mine but I think it will be taking the scenic route via two states capitals due to it and my origin. 

Playing amateur Ham today my little baofeng turned up - stock antenna is  so I have used most of my coax test leads joined to get it up a small pole  Hitting a repeater 30+km away so not terrible even with that dodge. Discone and a proper pole in the near future for this and the SDR playing.

And this slightly crusty PAT box I scored for not to much. Scrubbing brush and industrial detergent time.

edit: Photo of what is under the bonnet. ATMEGA84 based. Much safer to scrub the outer with the electrics out.

So... a slightly more automated and lower voltage version of a Megger? Looks like it's intended to be a workplace safety type bit of equipment; test your power tools in the shop on a periodic basis to make sure your grinder-monkeys aren't killing themselves with ghetto-rigged or otherwise abused tools, right? Over here that would be the demesne of an OSHA-compliance auditor...

Or do you guys still have some form of public safety office that actually audits the safety of appliances that are used in public places? 

We have a  AU/NZ standard thing called Test and Tag that tries to improve safety. In some cases it is insisted on by companies, events etc. Personally I think it is a wank for bureaucrats as that 'safe' lead can be cut tomorrow still used and be dangerous and not be found until retested in a year.  But the rabid capitalist I am say shutup do the course and take the $ 

The course is BS too can have ZERO skills going in and two days later be certifying electrical safety 

https://www.worksafe.qld.gov.au/injury-prevention-safety/electricity/electrical-equipment-and-tools-testing-and-tagging

[mnementh]

Solartron uses some novel scheme for interconnecting the boards. These contact combs (lacking a better word) can be slid out and back again. This, however, gets a bit tricky when you can't see the contacts, as this comb is easily tilted a bit and misses them. It also means that operating the instrument while the boards are separated (so you have easy access to the base PCB) is not possible.

The 7075 is worse

Imagine having the red plastic carrier between the circuit boards, and not being able to see between the boards without removing them from the case.

Separating the boards is easy, reassembling them requires some trial and error.

I really wonder what those designers think when they're choosing solutions like these. In manufacturing you can cope with that by using specialized tooling, but when they need repairs?

And these instruments are meant to be repaired! I cannot think of a viable excuse. Oh, sure I can: cost.

Actually, I can answer this question. These are not "just some annoying connector". These connectors were designed for a specific purpose, in conjunction with NASA and the major aerospace manufacturers of the time.

The purpose is to make the most reliable, lowest possible contact resistance connection that maintains that quality of connection over time under exposure to constant vibration and repeated cycles of heating/cooling. These are an avionics connector; they have to be rated for a service life of 2-3 decades in active use. Each of the connectors themselves has 4 or 8 individual HGE contacts; one or two on each of the 4 sides of the pin. Each of those contacts has a nickel-stainless leaf-spring behind it to maintain tension. There is a LOT of high-precision manufacturing involved in these little connectors. When you're dealing with this kind of equipment, convenience and cost are NOT nearly as important; they are expected to be serviced by experienced, highly-skilled technicians used to working in an aerospace environment and working on/with laboratory-grade equipment.

Those "captive" connectors are made that way for a reason: so there is no way they can physically be accidentally "not plugged in all the way". The dimensions of the pins will be such that if the PCBs are screwed down, no matter which set of connectors the pins tend to "float" towards, all contacts will be well-engaged on the surfaces of the pins because the plastic bridge bottoms out on one or the other PCB. If your device is properly engineered, you will see that all PCBs in the "stack" which are using that connector will be designed to be removed from the case as a unit for service, so alignment of the individual connector bridges is much easier to manage.

Seriously... we're talking a quantum level higher of engineering here than most of us are used to working with or working on. I only know about it because of my first gig straight out of Tech school; a specialty contract electronics manufacturer who was later "absorbed" by Raytheon.

Nowadays there are a number of variants of this original design; some have only two contacts per pin and some omit the stainless steel leaf-spring assembly for cost. This is the usual corporate cost-cutting at work; making something cheaper that LOOKS like the aerospace-grade connector but isn't rated for "mission-critical" assemblies where human life is on the line. Bean-counters making engineering decisions. 


Cheers,

mnem
 

[mnementh]

Sounds more promising for low speed DC fans  Still waiting on mine but I think it will be taking the scenic route via two states capitals due to it and my origin. 

Playing amateur Ham today my little baofeng turned up - stock antenna is  so I have used most of my coax test leads joined to get it up a small pole  Hitting a repeater 30+km away so not terrible even with that dodge. Discone and a proper pole in the near future for this and the SDR playing.

And this slightly crusty PAT box I scored for not to much. Scrubbing brush and industrial detergent time.

edit: Photo of what is under the bonnet. ATMEGA84 based. Much safer to scrub the outer with the electrics out.

So... a slightly more automated and lower voltage version of a Megger? Looks like it's intended to be a workplace safety type bit of equipment; test your power tools in the shop on a periodic basis to make sure your grinder-monkeys aren't killing themselves with ghetto-rigged or otherwise abused tools, right? Over here that would be the demesne of an OSHA-compliance auditor...

Or do you guys still have some form of public safety office that actually audits the safety of appliances that are used in public places? 

We have a  AU/NZ standard thing called Test and Tag that tries to improve safety. In some cases it is insisted on by companies, events etc. Personally I think it is a wank for bureaucrats as that 'safe' lead can be cut tomorrow still used and be dangerous and not be found until retested in a year.  But the rabid capitalist I am say shutup do the course and take the $ 

The course is BS too can have ZERO skills going in and two days later be certifying electrical safety 

https://www.worksafe.qld.gov.au/injury-prevention-safety/electricity/electrical-equipment-and-tools-testing-and-tagging

So this is primarily workplace safety then, like our OSHA? Not appliances exposed to the public, like washing machines, coffee pots & waffle irons used in hotels and such? Or is it SUPPOSED to be both, but like here, since the general public doesn't have any unions looking out for them, they only pay lip service to the latter and do as little of the former as they can fudge on paper?

Personally, I feel the opposite way about it... it's important, and it should be MORE FREQUENT than once a year. We shouldn't let corporate whinging outweigh essential issues of safety like this.

But then, you know, they'd have to actually pay for a PERSON to do those tests... and that would cut into the profit margin; the CEO might have to settle for First Class instead of taking the company jet to Las Vegas. We can't have THAT. 

mnem
Cynical? MOI...? Perish the thought...  

[Ero-Shan]

Solartron uses some novel scheme for interconnecting the boards. These contact combs (lacking a better word) can be slid out and back again. This, however, gets a bit tricky when you can't see the contacts, as this comb is easily tilted a bit and misses them. It also means that operating the instrument while the boards are separated (so you have easy access to the base PCB) is not possible.

The 7075 is worse

Imagine having the red plastic carrier between the circuit boards, and not being able to see between the boards without removing them from the case.

Separating the boards is easy, reassembling them requires some trial and error.

I really wonder what those designers think when they're choosing solutions like these. In manufacturing you can cope with that by using specialized tooling, but when they need repairs?

And these instruments are meant to be repaired! I cannot think of a viable excuse. Oh, sure I can: cost.

Actually, I can answer this question. These are not "just some annoying connector". These connectors were designed for a specific purpose, in conjunction with NASA and the major aerospace manufacturers of the time.

The purpose is to make the most reliable, lowest possible contact resistance connection that maintains that quality of connection over time under exposure to constant vibration and repeated cycles of heating/cooling. These are an avionics connector; they have to be rated for a service life of 2-3 decades in active use. Each of the connectors themselves has 4 or 8 individual HGE contacts; one or two on each of the 4 sides of the pin. Each of those contacts has a nickel-stainless leaf-spring behind it to maintain tension. There is a LOT of high-precision manufacturing involved in these little connectors. When you're dealing with this kind of equipment, convenience and cost are NOT nearly as important; they are expected to be serviced by experienced, highly-skilled technicians used to working in an aerospace environment and working on/with laboratory-grade equipment.

Those "captive" connectors are made that way for a reason: so there is no way they can physically be accidentally "not plugged in all the way". The dimensions of the pins will be such that if the PCBs are screwed down, no matter which set of connectors the pins tend to "float" towards, all contacts will be well-engaged on the surfaces of the pins because the plastic bridge bottoms out on one or the other PCB. If your device is properly engineered, you will see that all PCBs in the "stack" which are using that connector will be designed to be removed from the case as a unit for service, so alignment of the individual connector bridges is much easier to manage.

Seriously... we're talking a quantum level higher of engineering here than most of us are used to working with or working on. I only know about it because of my first gig straight out of Tech school; a specialty contract electronics manufacturer who was later "absorbed" by Raytheon.

Nowadays there are a number of variants of this original design; some have only two contacts per pin and some omit the stainless steel leaf-spring assembly for cost. This is the usual corporate cost-cutting at work; making something cheaper that LOOKS like the aerospace-grade connector but isn't rated for "mission-critical" assemblies where human life is on the line. Bean-counters making engineering decisions. 

Thanks for the lesson. I stand corrected.

But with a little good will they could have been augmented by some sort of guide that helped inserting them correctly. If the pin doesn't sit in the contact all the excellent properties will be lost. But you will not be immediately aware of that, as they will probably make contact on the outside.
Or maybe I'm just nuts.

Just learned something new.

[mnementh]

Ehhhhhh... it's a completely different design ethic; the polar opposite of mass-production. The point is that the connector itself be open as needed to be subject to visual inspection. This is the kind of gear where every unit is tested, inspected, and signed off on by a person before it is put into service or returned to service after repair/maintenance. Part of that "intended for use/service by trained technicians" thing.

This isn't an iPhone we're talking about, where a popped-loose connector is a mere annoyance. 

mnem
 

[worsthorse]

Quote from: mnementh on Today at 06:56:31

   

Yes that's a Heath Voltage Reference Source from the M-E Lab Components series   (Snippity)   I will probably make sure it works, calibrate it, play with it a bit to see how accurate it is and then ask if anyone more interested in collecting Heath gear than me wants to buy it.

And how I came to to be introduced to the trash barrel, well that's a story for another evening.

Yummy analog goodness from the golden age of American Electronics!     Please, do tell!

mnem

Okay, since you asked.  This is TL;DR material... 

I went back to visit the guy who saved the workshop from the dumpster, this time to go through boxes of components, and to give him cash from the stuff I sold for him.  We were at it for about an hour when he said, So my next door neighbor also got some stuff. Do you want me to ask him if you can look at it?  

A few minutes later I met the fellow, who leads me to his van, which is full of amateur radio gear and then to the side of his house, where I discover what looks to be three or four hundred dollars worth of cables, test leads, and small electronics left in the rain, and a garbage pail filled with a random collection of meters, new coax, and random trash.

/begin rant 

Turns out this was the man who trashed all the manuals and documentation. He wanted the storage cabinets, so he wheeled them into the driveway and upended them, dumping approximately 100 linear feet of original Tektronix and HP manuals, along with a whole collection of databooks, onto the ground. Then he brought over a wheel barrow and started dumping parts bins full of components into it.  That's when the guy I have been working with saw what was going on and stopped him.   

  was he thinking? He destroyed stuff he could have easily sold for some freakin' metal storage bins that he could buy for less than a hundred bucks.

In a rare display of adult restraint, I didn't start cursing, screaming or sobbing when I heard the story. I avoided looking at all the test cables ruined by the rain, quietly went through the trash barrel, extracted the Heath VRS, gave him twenty bucks and left the rest.  He offered to sell me everything he took out of the workshop. I politely declined. Given the nature of the conversation and his expectation that what he had was worth tens of thousands of dollars, I imagine that it will all be there when goes on to his reward.

   /end rant

I went back to my now-friend's garage, talked a bit about how to get the rest of the stuff out of his garage, sorted some more parts, and called it a night. Before I left he remembered two databooks that weren't destroyed and got them for me. The Moto RF device books from the late 80s, a nice find.

I am going to poke around and see if I can find a schematic or manual for the VRS but I don't think I will put a lot of effort into it as I don't think I would use it on my bench and some Heath nut will get more pleasure out of it than I will. I am just glad I saved it from that goofball.

[tggzzz]

Solartron uses some novel scheme for interconnecting the boards. These contact combs (lacking a better word) can be slid out and back again. This, however, gets a bit tricky when you can't see the contacts, as this comb is easily tilted a bit and misses them. It also means that operating the instrument while the boards are separated (so you have easy access to the base PCB) is not possible.

The 7075 is worse

Imagine having the red plastic carrier between the circuit boards, and not being able to see between the boards without removing them from the case.

Separating the boards is easy, reassembling them requires some trial and error.

I really wonder what those designers think when they're choosing solutions like these. In manufacturing you can cope with that by using specialized tooling, but when they need repairs?

And these instruments are meant to be repaired! I cannot think of a viable excuse. Oh, sure I can: cost.

Actually, I can answer this question. These are not "just some annoying connector". These connectors were designed for a specific purpose, in conjunction with NASA and the major aerospace manufacturers of the time.

The purpose is to make the most reliable, lowest possible contact resistance connection that maintains that quality of connection over time under exposure to constant vibration and repeated cycles of heating/cooling. These are an avionics connector; they have to be rated for a service life of 2-3 decades in active use. Each of the connectors themselves has 4 or 8 individual HGE contacts; one or two on each of the 4 sides of the pin. Each of those contacts has a nickel-stainless leaf-spring behind it to maintain tension. There is a LOT of high-precision manufacturing involved in these little connectors. When you're dealing with this kind of equipment, convenience and cost are NOT nearly as important; they are expected to be serviced by experienced, highly-skilled technicians used to working in an aerospace environment and working on/with laboratory-grade equipment.

Those "captive" connectors are made that way for a reason: so there is no way they can physically be accidentally "not plugged in all the way". The dimensions of the pins will be such that if the PCBs are screwed down, no matter which set of connectors the pins tend to "float" towards, all contacts will be well-engaged on the surfaces of the pins because the plastic bridge bottoms out on one or the other PCB. If your device is properly engineered, you will see that all PCBs in the "stack" which are using that connector will be designed to be removed from the case as a unit for service, so alignment of the individual connector bridges is much easier to manage.

I don't doubt that they are high quality connectors.

But the 7075 has not only some "captive" connectors (as I described) but also some non-captive connectors (as shown by Ero-Shan), and some very non-vibration resistant connectors on the same board. I don't see any good reason for that.

Captive and crap side by side in the first pic, non-captive in the second pic.

[tggzzz]

Ehhhhhh... it's a completely different design ethic; the polar opposite of mass-production. The point is that the connector itself be open as needed to be subject to visual inspection.

Not the 7075, as per pictures!

[mnementh]

I was explaining the why behind the connector and how it was designed; not behind the engineers at Solartron who specced it.
Who knows what shit they were smoking. 

mnem
 

[mnementh]

There are a lot of considerations made when engineering a product, other than just "what is the best part that can do the job".

The captive vs non-captive may be part of process control; they may have a test harness that plugs into that assembly for testing or calibration at a certain point in assembly, and then is replaced with the connector bridge. Maybe they ran out of the captive connector bridge during a run and the non-captive version was subbed to keep production rolling. Maybe they discovered a clearance problem during the run and that was the least expensive resolution that got them back in production.

The circuit itself may affect these choices; on a bit of test equipment, power conditioning is paramount... in the power supply section, having a low-resistance connection of a given current capacity is mission-critical to keep the entire unit functioning within spec, especially if, for example, you have pass elements and regulation on one board, but need voltage sense at the load on another board. However, serial comms between boards are much more resilient; their connection can function perfectly fine with resistance of a few ohms. Connections to keypads are similarly resilient.

Equally important design considerations have to do with business; you may have 150,000 of a given type of connector that will exceed spec in a warehouse bought for a contract that fell through or the buyer changed the spec at the last moment. What components you can RFC vary literally from quarter to quarter, even month to month. Here you have a product run of 120,000 units, and you have a factory with tooling for those connectors in storage until x or y happens.

By making a minor tweak in your design, you get to use most of those connectors that were paid for by someone else, your project can move forward this quarter instead of waiting for tooling, and your pointy-haired boss is happy because he just doubled his percentage on the project since you remembered those connectors from a prior project. You might even get two "Attaboy!"s out of this one.

Next revision will use the connector you specced out originally, or perhaps a completely different one because it costs half as much now and still fulfills the design requirements for contact resistance, frequency and no of mating cycles.

This kind of crap happens. Every. Single. Day. 

mnem
*hand-fabbing a clean garage*

[Kosmic]

Are you going to clean it up and get rid of the wax caps? Might not be the most useful scope by modern standards, but could still be a cool "conversation starter" in the lab. 

It survived for so long, it have to be restored by someone. If I do it, I would probably change all the electrolytic caps and carbon resistors. Also replace the bnc on the input to get a more authentic look.

I didn't really buy the lot for that particular piece so if someone is interested to pay for the shipping, could be yours 

P.S: I's large and heavy. Heavier than the Tek 485.

[Kosmic]

Tuesday evening's find, from a trash barrel being used as storage for various types of electronics and cables.

Look in great shape! You're definitely lucky.

[0culus]

Are you going to clean it up and get rid of the wax caps? Might not be the most useful scope by modern standards, but could still be a cool "conversation starter" in the lab. 

It survived for so long, it had to be restored by someone. If I do it, I would probably change all the electrolytic caps and carbon resistors. Also replace the bnc on the input to get a more authentic look.

I didn't really buy the lot for that particular piece so if someone is interested to pay for the shipping, could be yours 

P.S: I's large and heavy. Heavier than the Tek 485.

If I had the space and a dearth of projects I'd jump on it, but unfortunately I'm loaded up with oscilloscopes as is.  wait, is that heresy? 

[Kosmic]

I decided to try the old Dumont 274-A Oscillograph (I guess the word oscilloscope was not invented yet  ) I got part of the lot I fetched earlier this week. The inside was kind of clean but was still waiting for an explosion when I plugged-in the beast. I was astonished to see that it was kind of working. Probably need a good recap though

Talking about caps I'm probably too young but it's the first time I see those brown capacitor in wax. They look like wine bottle cork.

         

Are you going to clean it up and get rid of the wax caps? Might not be the most useful scope by modern standards, but could still be a cool "conversation starter" in the lab. 

Also interesting to contrast this "oscillograph" with the stuff Tektronix was making just a decade or two later and marvel about how fast 'scopes developed.

I'd be tempted to keep that beast original, and only switch it on occasionally when I felt brave enough to risk the fireworks & stinkbomb. Though it's obviously already been butchered with a BNC connector, so probably a pointless exercise. 

I remember reading an article in one of the antique radio forums back when... about a fellow who would warm up those wax caps, cut the outer layer off, stuff modern caps inside and pour the whole thing full of new wax. He even got to the point where he started making them for sale with small labels identifying them as period-correct "replica" parts. Talk about devotion to your hobby...

A good idea but I think I'm too lazy to keep the authenticity. Will probably simply use modern components. Will try to replace the bnc on the front though.

[worsthorse]

Look in great shape! You're definitely lucky.

I've been on a roll for a month or two, I think, but that's mostly because I've twice volunteered to help someone figure out what was in a pile of stuff they got unexpectedly so they could sell it, which worked out pretty well.  But I have my unlucky runs, too, as demonstrated by the shelf full of gear that I paid too much for, didn't understand, or couldn't repair. Most of 'em manifest all three qualities. 

[worsthorse]

I've been reading Analog Circuit Design during my afternoon breaks. Unfortunately, the article by John Addis, Good Engineering and Fast Vertical Amplifer Design has me pining for a 485 (again), so whenever I am at my desk and bored with my chores, I wander over to ebay and make moon eyes while I look at the o'scope offerings.

Yes, I am pathetic.   

[bitseeker]

So you thought it was finally over? Nah, you were wrong. It ain't over 'till the fat lady sings!

And the saga continues ...

... with the Solartron 7050 and its lookalikes.

Added!

This concludes the Solartron extravaganza. Now that the fat lady has done her part, the final curtain falls and I can go back to my lazy, slow pace. 

Thanks all of you for watching and not complaining about all those pics.

The more the merrier!

[bitseeker]

Now for a small relief.

Klein+Hummel Röhrenvoltmeter (VTVM) RV-12. According to radiomuseum.org it is of 1962 vintage.

And you can tell where they got their inspiration. It's almost a direct copy of the Heath VTVM's of the same era.

Precisely what I was thinking. Added the RV-12 to the POI.

[Cubdriver]

 



 

-Pat

[bd139]

Thus proving again that I’m in the wrong business.

Busy week and in not a good way.  Not much time for TEA. Haven’t even had a chance to read back through everything. 

[mnementh]

Same story here.

Garage has reached critical mass; it's fighting me with all it's got. If I can just power through a few more hot sticky afternoons, I'll make it to the downhill side; where I actually have enough room to work and get shit DONE.

Almost there. ALMOST.

mnem

[beanflying]

 

-Pat

Maybe the driver boards of this 'assembly' are some sort of hidden gift 

[beanflying]

Same story here.

Garage has reached critical mass; it's fighting me with all it's got. If I can just power through a few more hot sticky afternoons, I'll make it to the downhill side; where I actually have enough room to work and get shit DONE.

Almost there. ALMOST.

mnem

Time for a shipping container on the front lawn because that is always a classy look

[mnementh]

 

-Pat

Maybe the driver boards of this 'assembly' are some sort of hidden gift 

It feels more like selling pieces hacked off a corpse... I'm horrified to think what that backplane he chopped up used to be. The guy appears to be a "HAM Radio Gear" merchant... you'd think he'd be cognizant of the crime he has committed here. 

mnem
*Kix "goodstuff" in the 'nads*

[mnementh]

Same story here.

Garage has reached critical mass; it's fighting me with all it's got. If I can just power through a few more hot sticky afternoons, I'll make it to the downhill side; where I actually have enough room to work and get shit DONE.

Almost there. ALMOST.

mnem

Time for a shipping container on the front lawn because that is always a classy look

Naaahhh... most of what's there is going, going, gone... I just have to make myself suffer until I get to the point where it's less painful to leave it on the curb.

mnem
Denial: Not just a river in Eqypt anymore.