Test Equipment Anonymous (TEA) group therapy thread

[Saskia]

why do I see a dwagon licking 25 cps' wounds ?

No, DON't !

[tautech]

I'm still trying to pluck up the courage to get the 1kV supply working, without a schematic.

You've fixed CRO's with EHT's from 1.5 to 2.5 KV haven't you ?

[tggzzz]

I'm still trying to pluck up the courage to get the 1kV supply working, without a schematic.

I've got an UltraVolt 0-1kV adjustable DC to DC convertor I picked up for a song a while back. The plan is to, when I get around to it, stick it in a safe case with a pot on the front to provide an HV source for things like high resistance measurements and other general TEA purposes. When I got it I obviously needed to test that it was OK and worked properly and I don't mind telling you that I was a bit trepidatious about having a live, uncased, 1 kV source out on the bench.

My overgrown opamp has its output on unshrouded 4mm banana posts. The wires on the front panel connect the output to the feedback network, and are PTFE insulated with naked spade connectors. (See next post but one )

"Nicht fingergepoken" is as near as anybody debugging it will get to common sense.

[mansaxel]

I'm still trying to pluck up the courage to get the 1kV supply working, without a schematic.

I've got an UltraVolt 0-1kV adjustable DC to DC convertor I picked up for a song a while back. The plan is to, when I get around to it, stick it in a safe case with a pot on the front to provide an HV source for things like high resistance measurements and other general TEA purposes. When I got it I obviously needed to test that it was OK and worked properly and I don't mind telling you that I was a bit trepidatious about having a live, uncased, 1 kV source out on the bench.

I once was tasked with "There is no power in the food court on the festival camping, please investigate". Well, I jumped on the ATV, a colleague jumped on behind me, and we went, with multimeter and torch in hand to investigate. (it was so late in the evening that even in summer Sweden, it's dark outside)

The problem was traced to phase L1 being out (it's always L1. Why? Well, every idiot who builds a kebab stand on wheels puts the deep fryer AND the fridges/freezers on Phase 1, the kebab rack on Phase 2, and the LED festoon lights and a phone charger on Phase 3. Put four of those in the  same food court / fast food area, give them a 16A 3-phase outlet each and watch the fuse for L1 pop.)  L1 was out even on the part of the temporary construction site distribution cabinet that requires IEC 61010-1 Class IV meters. Upstream we went, and traced the AKKJ 3x90+90 (90mm² PVC insulated, PVC sheated three phases plus PEN braid aluminium cable, direct burial class) cable through the more or less sanitary conditions it had been laid, to the permanent distribution cabinet in a small forest near by. Here, it was pitch black. My helper held the Maglite, and I opened the cabinet. Inside, there are naked bus bars. And probably some 630A upstream fuses. I measured across the bars, all phases OK, found the fuse link that was blown, and pulled it. The puller tool is a sort of crossover between a set of forceps and a speculum, with a shield midway, and made of glass-reinforced plastic.



As I was somewhat focused on this, a festival visitor came up to the fence that held campers inside the festival (we were on the outside) and since he was obviously bent on relieving himself, we discouraged this, being in the danger zone of said activity. He complied (slowly, because he was properly drunk) and asked what we might be doing.

I simply answered "I'm staring at DEATH", fitted a new fuse on the puller, plugged it without too much arcing, closed the cabinet, and went to blackmail the food court operators for coffee.

[tggzzz]

I'm still trying to pluck up the courage to get the 1kV supply working, without a schematic.

You've fixed CRO's with EHT's from 1.5 to 2.5 KV haven't you ?

Yebbut there I had a schematic and circuit description, and the bits that might nibble (cf bite) are under a shroud and inside the case.

Here's part of the external wiring - notice the lack of a shroud and that it is outside the case. Back then metrologists were Real Men^(tm), just as when debugging analogue computer programs you thought about which end of the wires to move first when editing the program.

[tggzzz]

The puller tool is a sort of crossover between a set of forceps and a speculum, with a shield midway, and made of glass-reinforced plastic.

Not the kind of forceps that doctors/midwives carry, and which are not part of the curriculum for first-time mothers. Those professionals also carry even more gruesome tools.

[tautech]

Yebbut back at you tggzzz.

I gotta man up too today for the Lincoln plasma cutter on the bench that has some fault in the cutting arc supply.
Mains bridge, IGBT's or drive circuit IDK but will carefully work my way through it.
Gotta theory of operation overview diagram only that's little different from what I imagined anyways.

No more scared if it than I would be a 1 KV supply but at least I don't need to get the old AVO out to work on the thing.

[med6753]

hrmpf. Asked Threshold nicely for some schematics, and they told me that handing those out was against company policy.

You know who else does that? Toshiba. No joke. Want service documentation for your laptop? Go suck a lemon. 

[Saskia]

time for right to repair ...

[25 CPS]

   Speaking of which... mine arrived recently.

My wife got me two because... and I quote: "One for you to drink from, and one to put on the shelf with The Stick of Wisdom."   I'm the luckiest widdle dwagon in da wurrrllld...

mnem
...she GETS me.

I'm glad they made it in one piece.  I still have the remnants of mine in their boxes sitting on the shelf while I wait for a refund in case I need to take more pictures if it has to be escalated.  That packing job.  I don't know what to say about that packing job that I could post without getting in trouble.

Oh, man... I'm sorry. That must feel like rubbing it in your face...    I was just excited they got to me...

mnem
*toddles off to just be quiet somewhere*

Don't worry - given the packing job involved here, I'm just glad that at least a few of them got to where they needed to go without being smashed in the process.  All fifteen mugs could very easily have ended up getting destroyed with the way they were free to bang around inside their boxes.  I honestly think mine would've made it if they were held in place with anything even as simple or inexpensive as crumpled up newspapers or the weekly flyers instead of nothing.

[tggzzz]

Yebbut back at you tggzzz.

I gotta man up too today for the Lincoln plasma cutter on the bench that has some fault in the cutting arc supply.
Mains bridge, IGBT's or drive circuit IDK but will carefully work my way through it.
Gotta theory of operation overview diagram only that's little different from what I imagined anyways.

No more scared if it than I would be a 1 KV supply but at least I don't need to get the old AVO out to work on the thing.

If you turn the lights out you can probably debug it using only your eyeballs from 1m away.

[tautech]

Yebbut back at you tggzzz.

I gotta man up too today for the Lincoln plasma cutter on the bench that has some fault in the cutting arc supply.
Mains bridge, IGBT's or drive circuit IDK but will carefully work my way through it.
Gotta theory of operation overview diagram only that's little different from what I imagined anyways.

No more scared if it than I would be a 1 KV supply but at least I don't need to get the old AVO out to work on the thing.

If you turn the lights out you can probably debug it using only your eyeballs from 1m away.

Right back at ya !


Anyways, first real job of the day is to fill some 223 brass with powder and pills as I'm clean out of vermin bombs.

[Saskia]

Enjoy. But did your government not force you to turn in those nasty .223 killer weapons and use something more harmless ? Like a .338LM or so ?

Still looking for that Cheytac. ...

[tautech]

Enjoy. But did your government not force you to turn in those nasty .223 killer weapons and use something more harmless ? Like a .338LM or so ?

Still looking for that Cheytac. ...

Yeah lots had to hand in their AR’s but only bolt action stuff in my cupboard...can’t stand the rattling things.
Nothing bigger than 7.62 here.

At the bench now sorting brass.

[Cerebus]

hrmpf. Asked Threshold nicely for some schematics, and they told me that handing those out was against company policy.

You know who else does that? Toshiba. No joke. Want service documentation for your laptop? Go suck a lemon. 

Not any more. Toshiba last week sold off the final shareholding they had in laptops, that they had previously sold 80.1% of to Sharp. Toshiba are now completely out of the laptop business.

[bd139]

Good. Sack of cunts they are.

[mnementh]

I remember beating a coworker's Portege to death with a CF-28 back in the day... while the boss watched.  Fun times. 

mnem
I did it to save my sanity, I swear.

[tautech]

Enjoy. But did your government not force you to turn in those nasty .223 killer weapons and use something more harmless ? Like a .338LM or so ?

Still looking for that Cheytac. ...

Yeah lots had to hand in their AR’s but only bolt action stuff in my cupboard...can’t stand the rattling things.
Nothing bigger than 7.62 here.

At the bench now sorting brass.

And 40 pills later, done. Love my Chargemaster. 

[Neomys Sapiens]

I'm of the school that says it's a bad design if you can't substitute almost any BJT in a circuit with something very roughly similar and get a working properly biased stable circuit. Sure, you might miss on some critical applications (e.g. THD on low distortion power amplifiers can rely on having the right output transistors to get 0.001% THD rather than 0.01% with any old thing that's to hand) but for most things with non-critical, not pushing the envelope, design criteria then almost anything with suitable V_BCEO, h_FEmin/h_femin, F_t and P_tot ought to work by design.

I don't disagree, but when you are pushing designs to the limit you often end up relying on some "peculiar" parameter that is only found in one device. That is a problem when the device becomes unprofitable to make.

FFI, have a look at some of the discussions on sci.electronics.design. There's some very high quality info there, if you manage to avoid the politics!

Alternatively, have a look at the tables and "designs of the masters" in TAoE and the x-Chapters.

My precedessors did that (use the one peculiar device) ...with a 1kW pulse RF power transistor. Which is a way to ensure that absolutely nothing can be done about it or rescued from the design.
The company which made it did go off the market right when their design was approaching production.
And all it would have needed is another booster stage and a quad of devices for the main power stage.
Which would even have cost each less then half of the wonder transistor.
They bought around 200 of the beasts, prayed a bit to the transistor fairy and were gone.
When I started to look closer, I saw that they did not even do it right. They sacrificed linearity optimising for parameters completely unasked for.
Sometimes, when all this becomes especially unnerving, I wonder if it would be possible to hoist them on their own petard. Like pay and install a mole in their respective nowadays workplaces with the single task to make them bet all their assets on such a design and then leave them with the cripple. And I would not leave it to chance or the mole's inexperience. The second line of defects would be hidden deeper and be specially designed for them. I know that none of them did ever read up on failure modes.
But sadly, pedagogic vengeful engineering does not rank very high among the priorities of philantropist billionaires.

[Neomys Sapiens]

And now for something completely different: thermal stripper!

On saturday my 5 + 4 Euro thermal stripper arrived. Brand: Mentor-Strip.

This is a picture from the auction:


You surely have noticed this unusual plug. It is made of Bakelite and contains a phased controlled modulator.
The plug in detail:



The temperature can be set between 0 to 10 where
0 relates to ca. 35°C
5 relates to ca. 100°C
10 relates to ca. 150°C

With the silver screw one can clamp the scale.

Here we have the inhabitants of the bakelite case:



Interesting Triac they have used. No idea what brand it is, wasn't able to find a datasheet or some information about it.
The 369 is perhaps a date code.

The blades are heavily used and worn out. Maybe I'll find one day a good replacement for them.



I did also some testing with PVC and PTFE (the brown one) insulated wires.
Set the regulator to "5" the PVC stripping worked nicely.
But the PTFE even on "10" and after nearly 10 attempts was hardly impressed.



Will look further for a thermal stripper. I think, it would be really useful if one has to strip ribbon cables.
Not sure about the PTFE performance but this Mentor Strip thingie is hardly to be taken seriously. Maybe with better blades.

My Mentor Strip looks the same, but only as far as the handpiece is concerned. It is fitted with a white, rather thin and surprisingly heat resistant line cable and a normal Schuko plug.
I think that is a clear indicator that the phase control thing does not originally belong there. Same can be said of the red silicone power cable, which is at least of the double cross section than mine. The controller could be the problem with PTFE. Still looking for the datasheet.
I have some Quadracs (Diac/Triac combinations) which go by the designation Q4004LT. They are from Teccor, but the Logo does not match.

[mnementh]

Good. Sack of cunts they are.

Wait... what...? Is that a THING? Is this like available for production, or engineering samples only?

mnem
WARNING-NSFW  _↓

[Neomys Sapiens]

Good. Sack of cunts they are.

Wait... what...? Is that a THING? Is this like available for production, or engineering samples only?

mnem
WARNING-NSFW  _↓

Dear Mr. MNEM,

in response to your enquiry about a 'sack of cunts' we regret that we have to inform you that you obviously were not provided with our trademark quality products or with items, which might already have surpassed their intended service life and which were slated for disposal.
We assure you that our products are NEVER handled in such a careless manner as throwing them in some bag or sack would suggest. Generally, our products are available only as single items which are shipped in a quality protective fabric cover. Same holds true for the dual packaged items, which had been available on special occasions only. Mass distribution packaging is done by TRAYS with paper/cardboard seperators, which do safeguard against items sticking to each other. For reference, please use the enclosed picture.

Cuntcorp Ltd.
Customer Relations Spokesperson

P.S.: Please keep in mind that our products as well as any depictions thereof or reference to them are intended for the use of consenting, responsible adults ONLY! Do not open at work or in public areas.

[0culus]

Good. Sack of cunts they are.

Wait... what...? Is that a THING? Is this like available for production, or engineering samples only?

mnem
WARNING-NSFW  _↓

Why did I know it was Oglaf without even looking. 


 

[mnementh]

Good. Sack of cunts they are.

Wait... what...? Is that a THING? Is this like available for production, or engineering samples only?

mnem
WARNING-NSFW  _↓

Dear Mr. MNEM,

in response to your enquiry about a 'sack of cunts' we regret that we have to inform you that you obviously were not provided with our trademark quality products or with items, which might already have surpassed their intended service life and which were slated for disposal.
We assure you that our products are NEVER handled in such a careless manner as throwing them in some bag or sack would suggest. Generally, our products are available only as single items which are shipped in a quality protective fabric cover. Same holds true for the dual packaged items, which had been available on special occasions only. Mass distribution packaging is done by TRAYS with paper/cardboard separators, which do safeguard against items sticking to each other. For reference, please use the enclosed picture.

Cuntcorp Ltd.
Customer Relations Spokesperson

P.S.: Please keep in mind that our products as well as any depictions thereof or reference to them are intended for the use of consenting, responsible adults ONLY! Do not open at work or in public areas.

I'll take 4 dozen for my next board meeting; assorted flavors, ALL with sprinkles. 

mnem
Have your people get in touch with my people. Or have your people touch my people; whatevs...

[Neomys Sapiens]

Glad someone is taking FINALLY those sprinkles off our hands!