Test Equipment Anonymous (TEA) group therapy thread

[tautech]

Oxy is my weapon of choice

Was mine too at 14 when I went in halves with dad for a set. Happily he paid for the gas and rods and he got lots of stuff fixed and built in exchange.

I am useless on stick welding

LOL we all were once ! After piles of molten steel blow throughs are dancing all around you pinky's you learn real quick to keep the molten stuff in the weld pool. 

I have tried a well set up friend's MIG and liked it - never tried TIG - but I can't justify getting a good TIG setup for the little I would use it.

MIG is great and easier to keep control of the molten pool as it doesn't have the arc push of stick welding.
TIG is a lot like oxy in that it's quite versatile but more suited to small mass and/or thin metals. Good for Ali too but you really need HF start otherwise you risk contaminating the electrode if you stick it trying to get a start.

Technique is the key for both MIG and TIG as Mig require an uphand weld while TIG downhand like oxy.
Arc is much different and depends on rod types and welding positions with vertical mostly uphand and most other positions downhand. Practice and initially a good overseer can have you making fine welds in no time.

I still have the inherited oxy-acet regulators - the local gas supply company used to charge 'rent' on the cylinders - up to $300/yr - highway robbery.

Yep we got that obnoxious behaviour from the big 2 gas suppliers here too. The bastards used to sell bottles so with some investment you were able to exchange MT's and run just for the price of a fill but the buggers phased that out a few years back so I went to a new supplier that would fill anyone's bottles subject to being 'in test' for just the price of a fill. 

As a young lad managed to give myself 'zinc fume fever' - my GP wasn't aware of it (residential area) but the guys at my father's Uni metal workshop all had a good laugh!

I worked with quite a bit of galv pipe in those early days and for sure it's not pleasant to use just oxy on. Arc is lots better but still you can smoke the shop out with zinc fumes. I try to do all galv welding at the door so the breeze can carry the fumes elsewhere whereas with oxy the breeze is an enemy to be avoided but less so with arc.

[kleiner Rainer]

and now to something completely different:

Restoring a Kontron / Tabor Electronics DMM 4021 that was saved from the scrap heap:



Shown here measuring outdoor temperature with a PT1000 sensor. Replaced some caps with modern 105 deg low ESR types, adjusted it with the aid of my K2000 and built a new NiCD rechargeable battery pack.

More TEA p*rn:



Lots of Dale precision resistors, main voltage divider Caddock 1776-101, input components isolated from PCB by Teflon isolators, protection diodes low leakage in metal cans (PAD50 by Siliconix), ADC is a LD120/121 combo from Siliconix. The datecodes point to a manufacturing date of mid 1982. Price in Germany back then 1000DM.

The most interesting feature is "self calibration": by pressing otherwise unused button combinations you can check the accuracy of the DMM. There is a calibration assy on the main board:



You can see a collection of Dale 0.1% resistors for checking resistance and current, and a REF-02EJ precision bandgap reference in a metal can. It should have stabilized a bit during the last 38 years 

Another button combination allows to check the internal battery pack. During operation, the battery pack is trickle charged, as soon as the meter is switched off, charging with 150mA starts and runs as long mains is connected. This charging method works well with NiCd cells but wreaks havoc with NiMh. Luckily I had some cells from a power tool lying around that went into the new battery pack.

Main problem now is finding a schematic and calibration information. The schematic over at radiomuseum.org seems to be a bad scan of a seventh generation photocopy and is missing part of the power supply. Another problem are the plastic front and rear frames: they are extremely brittle and glueing them together didnt last for very long.

Apart from being a fun project, this DMM was my first one at work, 33 years ago...

Rainer

[VK5RC]

Oxy is my weapon of choice

Was mine too at 14 when I went in halves with dad for a set. Happily he paid for the gas and rods and he got lots of stuff fixed and built in exchange.

I am useless on stick welding

LOL we all were once ! After piles of molten steel blow throughs are dancing all around you pinky's you learn real quick to keep the molten stuff in the weld pool. 

I have tried a well set up friend's MIG and liked it - never tried TIG - but I can't justify getting a good TIG setup for the little I would use it.

MIG is great and easier to keep control of the molten pool as it doesn't have the arc push of stick welding.
TIG is a lot like oxy in that it's quite versatile but more suited to small mass and/or thin metals. Good for Ali too but you really need HF start otherwise you risk contaminating the electrode if you stick it trying to get a start.

Technique is the key for both MIG and TIG as Mig require an uphand weld while TIG downhand like oxy.
Arc is much different and depends on rod types and welding positions with vertical mostly uphand and most other positions downhand. Practice and initially a good overseer can have you making fine welds in no time.

I still have the inherited oxy-acet regulators - the local gas supply company used to charge 'rent' on the cylinders - up to $300/yr - highway robbery.

Yep we got that obnoxious behaviour from the big 2 gas suppliers here too. The bastards used to sell bottles so with some investment you were able to exchange MT's and run just for the price of a fill but the buggers phased that out a few years back so I went to a new supplier that would fill anyone's bottles subject to being 'in test' for just the price of a fill. 

As a young lad managed to give myself 'zinc fume fever' - my GP wasn't aware of it (residential area) but the guys at my father's Uni metal workshop all had a good laugh!

I worked with quite a bit of galv pipe in those early days and for sure it's not pleasant to use just oxy on. Arc is lots better but still you can smoke the shop out with zinc fumes. I try to do all galv welding at the door so the breeze can carry the fumes elsewhere whereas with oxy the breeze is an enemy to be avoided but less so with arc.

Glad to hear that I am not so far away from the average plugger!
The TEA gear-head in me wants a TIG unit but..........
Rob

[bd139]

I saw this earlier. An interesting Ikea rack hack which might suit TE use cases.

Buy two Ikea Lack tables (£6 here for the white one), turn one upside down and stick some Rill castors on it. The picture below doesn't depict it but drill some holes into the legs and stick the other lack surface on the top. Seems to fit 19" stuff nicely. Also turns into a nice side table for the living room 



Edit: I'm not sure how strong it is as the surfaces are made of fartboard and this is no med class job but it might suffice.

[beanflying]

Needs far more U's to be useful for real TEA 

I am thinking about building a bench topped Gear Rack but todays job is a flip top Router Table for last weeks repair.

[bd139]

That's rather cool.


You can add more U's by adding more Lacks. Although it'll probably increase probability of catastrophic carboard failure 

[Specmaster]

Needs far more U's to be useful for real TEA 

I am thinking about building a bench topped Gear Rack but todays job is a flip top Router Table for last weeks repair.

Not everyone goes in for collecting rack sized boat anchors.

[mansaxel]

Our equivalent over here has had a long and pretty serious article on EMC, co-written by some clued amateurs, the interference hunters at Elsäkerhetsverket (Electrical Safety Authority) and the technical manager of the local utility company where they went on a hunt and found a couple of isolators on a utility pole intermittently drenching the entire HF band in crap.

Now that's reasoned. All we get usually is some old luddites whining about all technological progression causing QRM on 80m so they can't exchange weekly ailment reports/

In other news, I'm not so done with amateur radio. Enabler Type 1, Mark 1 Mod 3, also known as The Wife, gave me both a NanoVNA and a Sirio stubby GP antenna for Christmas. Now I've finally gotten around to put them in use. The antenna went up on its pole last weekend, and I had the Messi & Paoloni 3/8" cable terminated in the antenna end, and with the free end hanging in a coil under cover.

(how the f do i rotate images? can't find any docs that work...)



Since I'm with BD139 on the virtues of water-logged coax, I try to protect it as much as possible. I try to have only N connectors for antennas, and this Sirio has it.  The exposed run from the pipe along the wall and into shelter under the house gets run through a length of flexible conduit:



Once I'm reasonably certain I'll reach the connector panel I cut the over length off and store it temporarily:



Finally, one sometimes has to solder away from the bench:



Aaaand it measures reasonably in length:



SWR is reasonable, I think:



First QSO has been had.

[tggzzz]

Edit: I'm not sure how strong it is as the surfaces are made of fartboard and this is no med class job but it might suffice.

They will be 1% stronger than is anticipated necessary for their intended use.

Sometimes Ikea gets it wrong, e.g. a 2m high cabinet mirror mounted on a fibreboard door. During delivery the mirror flexed sufficiently that the fibreboard creased.

Despite that, I like the "doing more with less" attitude of their engineering.

[kleiner Rainer]

the only thing stopping us is the lack of Lack at the moment 

Rainer

[bd139]

Edit: I'm not sure how strong it is as the surfaces are made of fartboard and this is no med class job but it might suffice.

They will be 1% stronger than is anticipated necessary for their intended use.

Sometimes Ikea gets it wrong, e.g. a 2m high cabinet mirror mounted on a fibreboard door. During delivery the mirror flexed sufficiently that the fibreboard creased.

Despite that, I like the "doing more with less" attitude of their engineering.

Indeed. I am actually rather impressed with the desk I bought from them but that wasn't their bottom end stuff. That is extremely well engineered. Thing is much stronger than the expensive ones we had in the office and the surface is very good quality.

As for the rest, agreed. There's a lot of Ikea stuff in this house and some of it is borderline and some quite good. The Kallax fabric drawers for example are crap but the units are good.

Sitting here I see 1x 2x4 Kallax unit, one coffee table, one desk, one table and chairs and one bookshelf from ikea

Killer Ikea feature is it's actually easy to get hold of their stuff and get it home compared to nearly every other outfit which requires negotiation on delivery, waiting weeks, hassle and then dealing with the company's bankruptcy almost immediately.

[Mr. Scram]

I saw this earlier. An interesting Ikea rack hack which might suit TE use cases.

Buy two Ikea Lack tables (£6 here for the white one), turn one upside down and stick some Rill castors on it. The picture below doesn't depict it but drill some holes into the legs and stick the other lack surface on the top. Seems to fit 19" stuff nicely. Also turns into a nice side table for the living room 



Edit: I'm not sure how strong it is as the surfaces are made of fartboard and this is no med class job but it might suffice.

They're unofficially called Lack Racks and are quite popular in some circles. Some build quite impressive stacks with them.

[kleiner Rainer]

I agree. My Ikea Poäng chair is over 25 years old and still going strong. I bought one when I moved into my own apartment, because I knew that they would stand abuse - my parents had some of them, that could be 40 years old now. Back in my youth, we went to the first Ikea in Germany, near Munich (opened 1974 in Eching). I still remember the friendly Swede with that funny accent handing us over our stuff (Subladensränksen - you cannot translate that!)

Rainer

[mansaxel]

As a young lad managed to give myself 'zinc fume fever' - my GP wasn't aware of it (residential area) but the guys at my father's Uni metal workshop all had a good laugh!

Milk is the cure, IIRC.

[Specmaster]

As a young lad managed to give myself 'zinc fume fever' - my GP wasn't aware of it (residential area) but the guys at my father's Uni metal workshop all had a good laugh!

Milk is the cure, IIRC.

It is indeed and also milk is supposed to be made available to paint sprayers, and IIRC shot blasters, not sure as to the reasoning behind it though.

[mansaxel]

I saw this earlier. An interesting Ikea rack hack which might suit TE use cases.

The Lack Rack Hack has been around for some time. I've got a very Ikeaified home, of course, since we're in Sweden. But no Lack Rack; I'm more of a Rittal person in 19" hardware. In this room, we've got sofa KARLSTAD, dining table like EKEDALEN with chairs, METOD kitchen upper cabinets mounted on the wall, and some TROFAST storage bins.

It's very well engineered to a price point. Which IMNSHO is the true art in engineering, doing things just right. Anyone can overspec, that's fairly easy, actually. But optimization is way harder.

And, it's easy to assemble. Just follow the fucking pictures. Don't -- unless you're Swedish, we start learning the IKEA train of thought as children -- skip steps and end up like smartasses usually do.

[med6753]

I've never even BEEN in an Ikea store.   And there isn't one in NY. The closest one is in Paramus, New Jersey.

Edit..... correction. There is one in Hicksville which is out on Long Island, NY. Way too far.

[Saskia]

@Med there is one right next to Newark Int'l.

Can anyone of our US friends look into getting https://www.ebay.de/itm/223981992003  this for me ? He declined my offers and said that he was not going to ship internationally.

Cheers
Saskia

[bd139]

I'm more of a Rittal person in 19" hardware.

Yes that's what we've got in our office and DC cages. Very nice racks.

[tggzzz]

It's very well engineered to a price point. Which IMNSHO is the true art in engineering, doing things just right. Anyone can overspec, that's fairly easy, actually. But optimization is way harder.

Precisely.

There is almost certainly an amount of Darwinian evolution in their stuff. The bad example I noted earlier ceased to be available.

[med6753]

@Med there is one right next to Newark Int'l.

Can anyone of our US friends look into getting https://www.ebay.de/itm/223981992003  this for me ? He declined my offers and said that he was not going to ship internationally.

Cheers
Saskia

Yep.... Elizabeth, New Jersey. Right across from Staten Island, NY. The one in Paramus is closer to me, about an hour away. I'm located about 75 miles north of NYC along the Hudson River. 

Edit...with regards to your request. Tried that once getting parts to AVG in the UK and it has turned into a royal hassle with customs. And cost me double in shipping costs.

[Mortymore]

I've been using IKEA furniture in the attic for shelving. I like Kallax, and I like to assemble what I call "LEGO for grown-ups"

[Saskia]

@med in that case I fully understand. Don't worry about it, there will be more zynq boards available.

[mnementh]

I just got back from the Px and the grocery; peeked in to hear Pat & Saskia gabbling about old vs new DSOs and found FireFlump didn't wanna talk to my mic, so I bailed. meh.

mnem
*toddles off to go walkies with the kiddles*

Interesting topic, especially as I was quite amazed to hear MNEMs faint praise for the much maligned 2430.
This scope was even wrongly described as an A/D hybrid akin to the 2335, which it isn't, because it is always sampling. After having used a slower DSO, it was the scope giving me the 'WHOA, that is what a DSO can do' effect back when I encountered it first. Tek 2430/2440 remains as my backup and it is the scope that you can expect me to operate even when half asleep. We just got very intimate over the time and I know where is what and what to expect. Apart from the known vulnerability of cooking chips when the fan fails, it is one of Tektronix major strikes.

Those who malign the 2430 have never had to work on a 2230, which was a true A/D hybrid; IIRC you could take the acquisition board right off and still use it after punching through all the POST errors.

The 2430 shares a lot of DNA with the rest of the 24xx family; I'd say those who maligned it were expecting it to be to DSOs as the 24x5s were to analog scopes. That is a wholly unreasonable expectation; Tek was inventing its own bleeding edge silicon at the time for all these machines, so anybody who was disappointed just had no idea what was possible given the tech of the era.

That said... I had my first such "Whoah... DSO!!!" moment with a 2230 in one of my last corporate EE gigs; that experience was why I bought/rebuilt the one which gave me so much trouble that I gave it away to a member here after using it for 10 years.

Oxy is my weapon of choice - as it was available - I am useless on stick welding - I have tried a well set up friend's MIG and liked it - never tried TIG - but I can't justify getting a good TIG setup for the little I would use it.   I still have the inherited oxy-acet regulators - the local gas supply company used to charge 'rent' on the cylinders - up to $300/yr - highway robbery. You can now get disposable oxy-acet set ups - terrible regulators but usable for the little stuff I use it for.
As a young lad managed to give myself 'zinc fume fever' - my GP wasn't aware of it (residential area) but the guys at my father's Uni metal workshop all had a good laugh!

That's what you get for trying to build with plumbing pipe.  (Never stopped me either  )

HF TIG is the only way to go for work where greatest strength without piling on bead after bead is required; things like race car & motorcycle frames, aircraft, etc. It is quite like welding with an electric flame; the way it works is quite magical once you get used to it and it quickly becomes your favorite form of welding for once you have the gear. Stick and MIG are for the heavy shit... TIG is for anything even remotely resembling precision work.

TIG makes the strongest weld with the smallest bead possible; while ANY welding weakens the parent metal with micro-crystalline fractures to some extent, TIG is exponentially less offensive as if done correctly by an experienced welder as dwell time to full penetration is much less than with MIG and stick welding, especially with materials like tubing and sheet. You soon find yourself welding things like m4 nuts to the insides of braked-metal project boxes and the like just because you can. 

I saw this earlier. An interesting Ikea rack hack which might suit TE use cases.      Buy two Ikea Lack tables (£6 here for the white one), turn one upside down and stick some Rill castors on it. The picture below doesn't depict it but drill some holes into the legs and stick the other lack surface on the top. Seems to fit 19" stuff nicely. Also turns into a nice side table for the living room 

Edit: I'm not sure how strong it is as the surfaces are made of fartboard and this is no med class job but it might suffice.

The 2 Lack tables hack has been a "thing" for 3DP enclosures for years and years... I expect this is just an evolution of that; or perhaps the other way around.    Still, not a bad way to "knock something together quick & dirty" when you need it.


mnem

[med6753]

Jupiter 2000 was the FG I took to university with me. I was the only one with a lab in the halls 

I could only afford to take some pliers/cutters, multimeter, and a homebrew 8038 oscillator.

I never used the oscillator since I could use those in the university labs.

I still have the multimeter, but don't use it.



45 years later, I use the cutters and pliers daily

That square wave and sine are from an 8038 circuit I built over 35 years ago. The output is fixed at 5Khz and 0.5V p-p. There's also a triangle wave at the same frequency/level. It's used as simple and quick check of scope function plus that's the burn-in torture rack too.