Test Equipment Anonymous (TEA) group therapy thread

[Vince]

But what would I do with such a thing, in the lab ?  Use case example please ?! 

Whenever you take a picture and post it here you put it in the frame. Casually yet prominently.

Sorry I don't understand what you mean ?! 

[Ice-Tea]

But what would I do with such a thing, in the lab ?  Use case example please ?! 

Whenever you take a picture and post it here you put it in the frame. Casually yet prominently.

Sorry I don't under what you mean ?! 

That'll teach me to reply without reading the last 20 pages I missed. I thought we were still on calculators.

I'll stick my foot in my mouth and continue to move the office to it's new location 

[McBryce]

Vince, ignore the Kelvin Heads.  I'm sorely lacking in temperature measurement too. I have the 2465 DMS with temp measurement capability with a home made probe but it reads about 4F high. 

FTFY... 

McBryce.

[Brumby]

I have a new toy, but I'm not allowed to show you 

So tempted to just "drop in" 

.... but I really don't want to be "That guy".

[Vince]

Fridge Timer Update

OK so I have wired up a 4060.

These old CMOs chips aren't as fragile as people say... Mine have been stored in a small plastic bin for 30 years, all teh chips entangled with each other, touching pins, me grabbiing and handling them with my big fingers with no ESD protection other than me discharging my fingers to earth just before grabbing the chips and..... freaking chip still works just fine !!! 

so first thing was to see if it's alive. I calculated that to get my 4.55Hz target frequency, I would need a 100ms RC time constant given, the formula in the datasheet for the built-in RC oscillator.
At first I wanted to put a 1uF cap with a 100K of course, as it's easy round numbers, but I couldn't do that because that means the second resistor needed in this oscillator, which needs to be 2 to 10 times larger than the R in the RC, would be 200 K to 1M, and my resistor selection stops at about 150K sadly. So instead I halved R from 100K to 47K, and doulbe C from 1uF to 2.2uF. this way I could use 100K for the second resistor.

Reset pin : I didn't even put an RC network because the datasheet doesn't call for it. They simply tie the pin to ground permanently and call it done, so I did just that...

Then.. I applied power...

As a first step I scoped the output of the built-in oscillator to see if it was running, and what the frequency was like. See below.

It worked just fine, this old chip is alive !

Frequency wise I got 4.15Hz at first, a bit low, a bit less than 10% too low. So I sped things up by about the same amount by replacing the 47K resistor with a 43K one. That brought the Freq up to 4.55Hz, spot on !     

Then I checked the dividing chain / counter outputs. 14 stages, number starting at Q1 not Q0.  Q1/2/3 and 11 are not available because of lack of pins on the 16 pin package. So the fastest output I could check was Q4, hence divides by 8. As you can see that works just fine 

So I will assume that the other outputs work too... and move on to the next step : add the NOR gate on the last 2 outputs to get the modified duty cycle.
I have no 4001 CMOS so will be trying with a TTL equivalent. Should still work I think... the totem pole output of the 4060 should be plenty capable enough to sink the current required to drive a TTL input low. As for logic high, it does not require any drive so it can only work I guess ! 

Let's see !!

[tggzzz]

Wow that HP 95LX MS-DOS computer looks cool 

It is. It even has Lotus 123 in ROM, invoked via the blue 1²3 key.

The manual is ~4 times the volume of the computer, and much heavier!

The later 100LX was slightly improved. There was even the OmniGo 700lx where you could ram a Nokia 2110 mobile phone up its backside. I wonder why that didn't catch on? (Hint: Nokia did it right)

[Specmaster]

The calculators I have in my collection are many and varied, some I can't even remember their model numbers or precisely where I put them for storage but here are ones that I can quickly lay my hands on, these do not include the numerous 4 bangers and printing ones, which bd calls mechanical spreadsheets 

My first calculator used professionally was a Commodore SR4912, purchased while I was at college during my apprenticeship, and it is with me today and in use photo below.

Sinclair Scientific,
Commodore PR100 Photo below,
Ti 58 In the process of swapping out the rechargeable battery pack.
Ti 2200 (Cheque Book calculator)
Ti Ba Solar,
Casio FC-100,
Casio FX991D,
Ti 85 (2 off these)
Casio FX9860G,
Ti-nspire (P-0708E) with the optional extra TI84+ keyboard
Ti-nspire (P-0810C) with the optional extra TI84+ keyboard
Ti 92
Ti PC100C Printer for the early Ti series calculators

All of the above are all fully functional, I also have a NIB NOS Casio graphic (colour calculator, whose model number I forget), 2 off Ti 92 non functional for parts etc.

[mnementh]

So you mean they aren't bad ones, I can just buy the first random generic nu branded super cheap one on Ebay or XYZ, and it will be just fine ?
3 bucks at that ?!

Well OK will buy one real soon then ! 

The MX54C can use either a PT100 or PT1000 thermocouple, if I believe the documentation I have, below.

I must be losing it... more than usual... I've looked that pdf over 3 times, and I can't see where it says anything about using the PT100/1000 sensors.

mnem
*toddles off to nuke a power controller*

Eh ?! WTF...... Oh, I see !!!  Looks like I attached the wrong file, I attached " Metrix MX 50 Series.pdf " instead of " Metrix MX 50C Series.pdf " , my bad sorry ! 

It's on the 3rd page, it shows a table listing / comparing the specs of all the models in the range. MX54C is third column. Temperature stuff is near the bottom.

I corrected my post, and also attached the correct PDF here as well so you don't have to scroll back. See how nice I am ? I would do anything to seek Dwagon's forgiveness 

LOL... nothing to forgive. We've all done it. Good to know I'm not losing my mind... Well, at least, that this time the problem wasn't all in my head.   

mnem
Bien sûr, la fiche technique que vous avez postée ici est en français... juste pour me torturer, non... ?

[HighVoltage]

Wow that HP 95LX MS-DOS computer looks cool 

The 95LX and later 100LX were truly amazing little machine in well built HP quality.
And they were ahead of its time.

I was a listed developer at that time for hardware add on parts and had all the development tools and hardware supplied by HP. The good old HP days...

[mnementh]

A package arrived     A clue inside.   New stuff for a change  . Damm enablers 
At least I can undo odd size connectors with flats up to 2mm wide without leaving plier marks. I have proper slim spanners for the common sizes.

* in best youthful sing-songy voice* Yooooou're welllllll-commmmmmmme!  

I also have the thin Crescent wrench; IMO it's a lifesaver tool everybody should have at least one of. I quite like that this particular one is scaled fractional on this side and mm on the other.

https://www.amazon.com/Channellock-806SW-Xtra-Adjustable-Wrench/dp/B01N52WJRT/

https://www.amazon.com/Channellock-8SWCB-WideAzz-Adjustable-1-5-Inch/dp/B00VBPY91O/

https://www.amazon.com/Amazon-Basics-8-Inch-Adjustable-Wrench/dp/B08L6VGZF7/

https://www.amazon.com/dp/B07HR5N7T2/

mnem
Go on... git you some... 

[Vince]

So you mean they aren't bad ones, I can just buy the first random generic nu branded super cheap one on Ebay or XYZ, and it will be just fine ?
3 bucks at that ?!

Well OK will buy one real soon then ! 

The MX54C can use either a PT100 or PT1000 thermocouple, if I believe the documentation I have, below.

I must be losing it... more than usual... I've looked that pdf over 3 times, and I can't see where it says anything about using the PT100/1000 sensors.

mnem
*toddles off to nuke a power controller*

Eh ?! WTF...... Oh, I see !!!  Looks like I attached the wrong file, I attached " Metrix MX 50 Series.pdf " instead of " Metrix MX 50C Series.pdf " , my bad sorry ! 

It's on the 3rd page, it shows a table listing / comparing the specs of all the models in the range. MX54C is third column. Temperature stuff is near the bottom.

I corrected my post, and also attached the correct PDF here as well so you don't have to scroll back. See how nice I am ? I would do anything to seek Dwagon's forgiveness 

LOL... nothing to forgive. We've all done it. Good to know I'm not losing my mind... Well, at least, that this time the problem wasn't all in my head.   

mnem
Bien sûr, la fiche technique que vous avez postée ici est en français... juste pour me torturer, non... ?

Your French is excellent, zero mistake. Very few French people could write this sentence properly these days... 

No I didn't mean to torture you, it's just that I don't chose what I find on Google, I get what I get ! 
But the previous / wrong doc was in English, lucky you ! 

[Vince]

Fridge Timer Update

OK so as planned next move was adding a NOR gate as Zoli suggested, connected to the last two outputs of the frequency divider in the 4060. Q13 and Q14.

Used a TTL gate because that's what I have. As I thought and hoped, it works just fine, no worries.

In order to check that the arrangement works as expected, I tried it using the two fastest outputs instead of the two slowest ones, so that I can scope it without having to wait for 2 hours for the screen to display the waveforms....

So, Q4 and Q5 it was instead. That means I could set the sweep speed to 2s/DIV, hence "only" 20 seconds to draw a screen... it's about tolerable.

I am glad I have a 4 channel scope.. today for the first time I get to take advantage of that !  I could scope both input of the NOR gate, as well as the output.
Combiscope being able to do digital, it's fantastic to get a beautiful clean stable trace with ultra slow signals here, which you can't do with an analog scope. Well, unless you have storage CRT but it's not exactly the vast majority of them, you will admit...

My combiscope really shines here, I love this scope   

The two inputs of the NOR gate, Q4 and Q5, are at the top of the screen. Output of the gate is last trace at the bottom.
Looks like it's working just fine, I do get a 25% duty cycle output !!! 

Thanks for the design Zoli !! 

OK so now next step is add a little transistor and a relay to power the fridge, and maybe an LED or two to indicate if the relay is open or closed.

[mnementh]

I want to design this thing, the time pressure / emergency makes it even more fun...

I would go into my cellar storage, fetch a industrial standalone controller with a range extending to 0...10°C (PT100-based, Philips, Siemens, ICE, Jumo, PCE - there is at least one around), and if I wouldn't find any, I would set up a controller using a S5-95U or -100U. Then jury-rig it into the place of the fridge thermostat.
Do you need a controlller now? (not the S5's of course, because they fall under the 'my preciousss' category.)

I would go out to my Man-Eating Black Cabinets™...   

   

The spoils of war; Bits o' Appliances collected during my daze working at the Ding & Dent Store. IIRC, this one operates from somewhere around -40°C to +150°C, and can be scaled in °Celsius or °Funkenkopft.

mnem
Yes, you may touch it.

[med6753]

Vince, ignore the Kelvin Heads.  I'm sorely lacking in temperature measurement too. I have the 2465 DMS with temp measurement capability with a home made probe but it reads about 4F high. 

FTFY... 

McBryce.

Cute. There is no calibration adjustment within the 2465 DMS for temperature. It relies upon the accuracy of the sensor. I purchased what I thought was the correct sensor and checked it in an ice bath and it read 33F as it should. But apparently it's not linear or for some other reason at room temperature it reads high.

[Zucca]

If you throw that HP 32s in evilbay at an insane price, somebody in this planet will pull the trigger.
The real question is, do you want to? 

[mnementh]

There is FreeBSD for Raspberry Pi.

mnem
"It's just like tryin' to fuck a alligator: A whole lot of thrashing about,
and even if you're successful, no good can possibly come of it." ~me

That is a perfect representation of the Raspberry Poo. It's not a computer; it's a bad idea which is really badly implemented wrapped in a layer of marketing under tight control by a rabid fanbase and moderation on their official forums. Eben and Liz can literally fuck right off. Putting FreeBSD on it is a folly at best when there are real, proper, non shite computers out there you could throw your efforts at. Even that cranky ass 12 year old spooge coated shitbox you got from a house clearance for nothing because the guy who was clearing it out didn't want to touch it incase he got Herpes is a better computer. It's also 100x less likely to fuck up on you even if it's limping along like a rabid squirrel and you have to scrape the jelly like layer of nicotine off it.

Oh, come now... it's perfect for its intended purpose: teaching high-school kidzz why you don't try to run Windoze on a Arduino. 

   
https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/msg3918314/?topicseen#msg3918314

No, seriously... my son is actually learning quite a bit with his Kano tablet... the entire ecosystem revolves around teaching in a "Programming Logic & Design 101" format, so it really does have some value in this application. 

They also work really well at teaching the value of straightforward code, robust mechanical design (by providing a horrible example; see link above) and are a great first lesson in the misery of how to navigate the treacherous waters of [insert functional construct here] dependencies... a life-skill every kid needs to learn as early as possible. 

mnem
 

[Kosmic]

Anybody's looking for a nice coffee table ? 

https://www.ebay.com/itm/224991657657

[capt bullshot]

Anybody's looking for a nice coffee table ? 

Obviously the original feet were lost, and some new ones (that were just around by chance) attached.

[mnementh]

PT100 & PT1000 sensors are thermistors;

That's not wrong in any sense, but they are usually called RTDs (Resistance Temperature Detectors) to differentiate them from NTC and PTC thermistors of mixed compounds.

Yeaahh... nfmax corrected me on this. I suppose I should have said "thermistor-type devices, not thermocouples"; my intent was to differentiate as of course a thermocouple generates a voltage proportionate to temperature.

Thanks for keepin' the ol' TinkerDwagon honest. I know picking nits like that one is part of being TEAnonymous...   

mnem

[mnementh]

And also missing from Vince's lab: a simple, commercial day or week timer switch. 

Agitator. 

mnem
Hey, Vince... what time is it...?

[bd139]

Anybody's looking for a nice coffee table ? 

https://www.ebay.com/itm/224991657657

Was half expecting to see a light bulb on top of it 

[mnementh]

A Capt. Hindsight Advisory:
'Always check all dimensions and parameters of an object, on which you need to rely!'

Yeah, fuck off, Captain. You are outranked by Major Displeasure anyway.

Why did I not notice that the nice little Fluke 115 is THICKER than the 79-III? 
So I did not gain any space at all AND had to rearrange the complete bottom tray of that toolcase. And because I wanted to be done with it, I performed this feat kneeling with no space around. Now I have some bruises (where the lid came down suddenly on my hand), somehow my knees have been reassembled in the most painful way possible and my back hurts like fuck.

And Capt. Hindsight also wanted to add that proper preparation of the workspace could have prevented this. To which I answered -censored- -censored- -censored- -censored- -censored- -censored- -censored- -censored-!

And note how it conveniently accepts a standard Type K thermocouple... 

mnem
*heckle-heckle*

[Peter_O]

The HP 35665A Dynamic Signal Analyzer is making some progress:

I got a NI PCI-GPIB card from 2002 with a kind of strange rectangular slot bracket for 37 Euro and a cheap chinesium GPIB cable.
Installed it into an older W10 system.
Fiddled with the NI libs a bit until device answers the ID? poll.
So card and cable seem to work.

Installed the Plotter emulator: http://www.ke5fx.com/gpib/7470.htm

Fiddled with bus master - eh, system controller - settings, addresses and knob pressing sequences, then it works. Excellent. 

[Specmaster]

Anybody's looking for a nice coffee table ? 

https://www.ebay.com/itm/224991657657

Was half expecting to see a light bulb on top of it 

Just plonk a normal table lamp on it, you can choose your own to suit your taste.

[med6753]

Anybody's looking for a nice coffee table ? 

https://www.ebay.com/itm/224991657657

Was half expecting to see a light bulb on top of it 

Just plonk a normal table lamp on it, you can choose your own to suit your taste.

What is it's intended use? Checking receive limits and noise floor of RF receivers?