Test Equipment Anonymous (TEA) : Discussion and Group Therapy Thread

[Specmaster]

All of these snow scenes are very picturesque to look at but an absolute nightmare if you have to go out anywhere. I just hope that you have all the requirements in to last you for a few days until conditions improve and your heating and power behave themselves.

So far this year, I have only had 1/4" of the stuff and that only lasted a few hours.

[tggzzz]

I don't mind deep snow, and have regularly cycled in it - slowly with much effort. The winter of 81'/'82 is etched in my mind since I had just moved into my first house and couldn't get coal since it was all frozen in the coalyard.

What I don't like is snow - melt - freeze. That's lethal: even cars slip sideways due to the road camber

[EC8010]

I found that if you attempt to cycle uphill in deep snow, the rear wheel spins. (This was before mountain bikes with chunky tyres became fashionable.) My CZ125 motorcycle coped very well with snow once I had got rid of the (supplied) Barum rectangular profile tyres. Yes, sometimes the back wheel would try to overtake the front, but the bike was low enough and light enough that a determined kick would put the back wheel where it belonged, and the lack of torque from a 125cc two-stroke meant that everything happened gently. The lack of grip didn't affect braking because the brakes were rubbish anyway.

[Zenith]

I didn't mind a few inches of snow when I was working, as long as it didn't hang around long enough to wear its welcome out.

[tggzzz]

The only motorised vehicles I've had are cars and a Land Rover. Hence when cycling in snow, spinning the rear wheel never happened

Vehicles of every kind behave poorly on sheet ice, and thaw-freeze produces that in abundance

[MED6753]

All of these snow scenes are very picturesque to look at but an absolute nightmare if you have to go out anywhere. I just hope that you have all the requirements in to last you for a few days until conditions improve and your heating and power behave themselves.

So far this year, I have only had 1/4" of the stuff and that only lasted a few hours.

Our municipalities are well equipped to handle deep snow. I was out the very next day with the CR-V because they wanted to plow out our designated parking. I also made a quick trip to a local store for a few items. The roads for the most part were clear and with the AWD on the CR-V any deep banks of snow that I had to drive thru it handled without any issues. 2 days later they wanted to plow out the visitor parking and that's were I keep Blondie's Accord and my Civic. Getting them dug out and moved was a bit dicey and took a lot of shoveling and wheel spin. Luckily site maintenance helped with that task. Our ground is still snow covered but it is melting. After that storm we had about 10 days of bitter cold and the temp never even approached freezing. We finally have temps significantly above freezing which is most welcome.

[AVGresponding]

I did have it higher, but it was blocking the racking behind. I have a lot of things stacked in "storage" in my bedroom...

My daughter's bedroom has been repurposed Still not big enough

Time to add an extension or two?

[Cubdriver]

Time to add an extension or two?

I think putting ANY vintage test gear made by Hewlett Packard or Tektronix in that room would be a very dicey proposition! Yike!!!

-Pat

[EC8010]

To be fair, he's used lightweight bricks. But nobody has told him about corbelling, and I'm not even certain that cement was involved. But the air-conditioning has been fitted. Hong Kong?

[MED6753]

Time to add an extension or two?

I think putting ANY vintage test gear made by Hewlett Packard or Tektronix in that room would be a very dicey proposition! Yike!!!

-Pat

Damn, that gives me some ideas.

[tggzzz]

I did have it higher, but it was blocking the racking behind. I have a lot of things stacked in "storage" in my bedroom...

My daughter's bedroom has been repurposed Still not big enough

Time to add an extension or two?

I don't know about other countries, but in the UK some properties are leasehold, some freehold, and a few are flying-freehold.

Checking wackypedia indicates there is a dual to flying freehold, i.e. creeping freehold.

[nixiefreqq]

My daughter's bedroom has been repurposed Still not big enough

Time to add an extension or two?

I don't know about other countries, but in the UK some properties are leasehold, some freehold, and a few are flying-freehold.

Checking wackypedia indicates there is a dual to flying freehold, i.e. creeping freehold.

is that a hammock hanging up there? how would you get to it?

[mansaxel]

What I don't like is snow - melt - freeze. That's lethal: even cars slip sideways due to the road camber

Friends who did armoured national service tell of the ways tracked vehicles behave. Cars are easy in comparison.

[AVGresponding]

To be fair, he's used lightweight bricks. But nobody has told him about corbelling, and I'm not even certain that cement was involved. But the air-conditioning has been fitted. Hong Kong?

Brazil

[AVGresponding]

Ok, had to rearrange the stack to accommodate the load:

IMG_20260220_134356500_HDR.jpg

Since I can't very well do without the counter, I've moved it to between the pc and the scope:

IMG_20260220_134514730_HDR.jpg

[MED6753]

This Winter is really getting to be a drag. After a week of above freezing temps and significant snow melt we are now under a Winter Storm Watch for Sunday into Monday for a potential of up to 8 inches of new snow. Spring can't come soon enough.

[Cubdriver]

It's sleeting here now.

-Pat

[MED6753]

Batten down the hatches.

[MED6753]

https://www.youtube.com/watch?v=rYKHg2dlg50

[MED6753]

My location is now under a blizzard warning. The storm is projected to move further inland.

https://www.youtube.com/watch?v=ZY8-YiIk6Vw

[tggzzz]

Back to our raison d'être...

I've recently tested a PSU set to 40mA 30V, with a 47ohm resistor so it should limit at ~2V. It output 30V for >100ms, then exponentially fell and undershot, and after a second got to the correct value!

Here are some results for PSUs available to me.

The good:

• AIM-TTI PL303QMD-P
• Rapid PS3025 / Manson EP-613
• Tenma T2-10505 / Korad KA3003D
• Power Designs 2020

The bad:

• Farnell PDD3502A

The ugly:

• Maplin N93CX / Manson NRP2050
• Eventek KPS305DF

[EC8010]

That Power Designs 2020 is lovely! Ooooh, I'd give one of those a home.

I fear I'm going to have to test my supplies...

I have a later version of the Tenma (dual 30V 3A); I use it for charging lead-acid batteries. It is horrible inside and clearly wouldn't pass any EMC tests despite being a linear supply.

[tggzzz]

That Power Designs 2020 is lovely! Ooooh, I'd give one of those a home.

It is gorgeous, now Paid £8 (plus £50 P&P). Acquisition story at: https://www.eevblog.com/forum/testgear/ ... msg1839581

Beware: many PDxxxx are 115V only. The 2020 needed the two primaries rewired in the usual way
https://www.eevblog.com/forum/testgear/ ... ach=910130

Also be careful about the voltage reference; the 2020 has an LM399 but I would check others.

I fear I'm going to have to test my supplies...

I have a later version of the Tenma (dual 30V 3A); I use it for charging lead-acid batteries. It is horrible inside and clearly wouldn't pass any EMC tests despite being a linear supply.

EMC doesn't concern me, fortunately.

Don't assume the overshoot occurs for other current limits; it might not. Also check the power-off behaviour.

The Tenma is basically OK, but it has never been a favourite of mine. The step up/down is convenient for a stimulus, but nowhere near as good as the 2020. Left/right to select the digit is the usual pain. I had to clean out the optical(!) rotary switches, because one had a tendency to jump spuriously - aargh! But I'm glad to have put that AIM-TTi in its place.

[EC8010]

Well worth the money. Replacing a transformer and even substituting an ADR399 wouldn't be a problem. It's those concentric switches and their knobs that are the tricky bit. I have some concentric switches, but it turns out they are nine positions on the outer and six on the inner. Sigh...

I have a plan to make a +/-0-20V 100mA current supply using a large BCD four digit thumbwheel switch feeding a BCD encoded precision DAC (reed relays and 0.002% wirewound resistors) both rescued from a mass spectrometer, but powered from four 12V 2.1Ah lead-acid batteries. The wooden box (ex-Cambridge Instruments thermocouple potentiometer) has been rubbed down up and revarnished, and I have a pair of matching 100mA meters. Whether it will actually make it to fruition is another matter.

[tautech]

A DIY PSU is a right of passage and not that hard at all unless current limiting is required......escaping magic smoke always teaches us lessons....