Test Equipment Anonymous (TEA) group therapy thread

[med6753]

Enough with all that newfangled gear!

Something be glowing in them there hills! 

Stop with the teasers.  Post up...what you got?

Well...

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The pulser was last called in... 2016. Did not see that coming 

Entirely appropriate that you need a hollow state device to test those new fangled solid state devices.   

Good deal.....clean it up and put it work.   

[mnementh]

@BU508A it's a parrot not a chicken 

   So quick cracking session. My DG822 now thinks it's a DG992. Interestingly apart from the screen decoration turning red, the output buttons changed colour from green to red at the same time 

To be honest: the first thing I'd do is to get rid of this stupid comma and replace the point with a comma (if possible). Confuses me all the time.   

One DECEASED parrot...?  

I've always found the presence of commas in the trailing digits annoying as fuck; even on integer counts. I've gotten rid of gear just because of that.     Compound that with your hideous red theme... I'd literally cringe every time I turn that thing on. But I WOULD probably put up with it for THAT price; for a while at least.   

mnem
*toddles off to do something... else.

[Ice-Tea]

Everything checked & works, except for the 575 that I haven't dared to turn on yet. I may need me some liquid courage. Which is a problem as I don't drink. Alcohol, that is.

[med6753]

Everything checked & works, except for the 575 that I haven't dared to turn on yet. I may need me some liquid courage. Which is a problem as I don't drink. Alcohol, that is.

Make sure it has the right size fuse in it. Then go for it. Give the full beans and stand back.

Oh and have a fire extinguisher handy. 

That's what I did initially with the 535A and got lucky

[Cerebus]

First thing I'd do is take those hideous bumpers off and burn them. Then put some nermal feet on the bottom. Fuckwits.

That's just barbaric!

[med6753]

Since there's been some interest in yesterday's drama with the 485 delay line tomorrow I'm going to investigate how/why it's open and try to fix it. I don't have a TDR so it's gonna be strictly hunt and peck and hopefully I'll get lucky.

[BU508A]

Since there's been some interest in yesterday's drama with the 485 delay line tomorrow I'm going to investigate how/why it's open and try to fix it. I don't have a TDR so it's gonna be strictly hunt and peck and hopefully I'll get lucky.

 

[URI]

My BM800 arrived today - and I've set it up.  Mechanically reasonable for the price (sub AUD$30, delivered). 

Sound quality still being assessed, but the noise floor is too high for me.  I've tried direct into my sound card and using the USB sound card supplied and both aren't too different.

The instructions (in the best Chinglish) indicate running 48V phantom power can improve the noise and level.  Might just give that a go... when I get around to it.   

Supplying 48V phantom power will certainly raise the SNR of every condenser mic, but don't expect too much from the BM800...
Without phantom power the sensitivity of condenser mics is rather low so much gain is needed to get a reasonable sound level out of them. The result is that bad SNR you observed.

[mnementh]

First thing I'd do is take those hideous bumpers off and burn them. Then put some  nermal feet on the bottom. Fuckwits.

That's just barbaric!   

Really...? What other good use is there for nermal feet...?    

Maybe not the kindest thing to do to a perfectly good AWG, but then... we ARE talking about a DG2102. Somehow it seems a fitting end for both.

mnem
I KNEW you'd notice.

[mnementh]

Since there's been some interest in yesterday's drama with the 485 delay line tomorrow I'm going to investigate how/why it's open and try to fix it. I don't have a TDR so it's gonna be strictly hunt and peck and hopefully I'll get lucky.

*casts a prayer to Ifni for med's poor masochistic soul*

mnem
"...Dominy, Dominy, Dominy... you're all Catholics now..." ~ Firesign Theatre: Waiting for the Electrician or Someone Like Him

[Specmaster]

And speaking of something huge and heavy......I'm going in possibly never to return. 

See you clearly like a little junk in the trunk  This wee beasty isn't that big..... compared to a truck

What do you mean, not that big, it even comes with its own wooden pallet! 

[Cubdriver]

And speaking of something huge and heavy......I'm going in possibly never to return. 

See you clearly like a little junk in the trunk  This wee beasty isn't that big..... compared to a truck

What do you mean, not that big, it even comes with its own wooden pallet! 

Yeah, that beast is for damned sure a back (and possibly bench) breaker!!  It will also help keep your house from blowing away in the event of a tornado.

-Pat

[Ice-Tea]

Doubt you got this 48kg monstrosity beat, though 

[capt bullshot]

I believe it's less than 48kg, but I've got two of them:




9.6kW (60V, 160A) each - your (modern) average household power supply would be fully loaded with them

[mnementh]

From the BORED SHEEPLESS IN THE GREAT WHITE NORTH Dept...



So, after another round of trawling the sea of shit known as the intardnet 'til my eyes water trying to research how to get started in MAME, I gave up and decided to play a little with something that requires little to no mental wattage. Initial testing just plugging in for a few seconds indicate that while it is quite bright, it certainly doesn't feel "20W of LED" bright. Powered up with no heat-sink, I find I can hold the module with my fingers directly under the 25mm² LED array for ~20 seconds before it gets uncomfortably hot; based on previous experiments with DC-powered LED modules this suggest 10-12W real LED power.

The numbers support a 20W rating; if you do the math it calculates out to 21.40W at 121.6VAC applied. Of course, the Devil is in the details; that assumes an ideal Power Factor of 1.0 for the LED driver. After scrutinizing the Amazon listing and several others like it, of course I found no mention of the PF of this module; so I did a little research on AliEx.  Turns out these are, as I suspected, a commodity LED lighting module available all over AliEx in 54x54mm (hence the F5454 designation), 60x60mm and 60x40mm footprints in outputs from 10-100W, for $2-10 per module: https://www.aliexpress.com/wholesale?catId=0&initiative_id=SB_20200311103841&SearchText=220v+COB

But after looking at dozens of listings, I still found no mention of the PF of these COB LEDs.  After poking around the module with my meter, I was not able to accurately measure the voltage drop across the COB LED array, though I did manage to break a tip on my cheap Chinese probes; after that, I decided to take what I know about most COB LEDs and extrapolate.

VF is usually ~3.2 for White LEDs; a few tenths above or below. Each LED chip in the COB is usually 3 elements in parallel with a drive of ~20mA each. There are 8x9 chips on this COB LED; so now we can do some theoretical maths: 8 x 9 = 72 chips. 0.06A x 3.2V = 0.192W/chip. 0.192 x 72 = 13.824W total. Hmmm...

My experience with LED lighting shows there is a huge variation in the Power Factor of the different LED drivers available; from an optimal PF of ~0.95 to as low as 0.65 for some really wasteful designs. Usually, higher PF comes at a cost... more dollars for better design & quality parts, so expecting high PF from a module available for US$2-3 a copy shipped is probably not reasonable.

So... a random finger in the air calculation for our module of 121.6VAC x 0.176A x 0.7 PF = 14.98 LED watts. Not that far off my 13.8 watts Wild-Ass Guess, and very typical of the kind of "optimistic ratings" we all know are common with such commodity electronic modules.

   But the takeaway for me is much simpler: While this module is probably not a good choice for the desk lamp it was bought for, it may well be perfect for a Luxo KFM series 6" swingarm magnifier I picked up recently for next to nothing... I need to do some trial with the module to see if I like it better than the old-school T9 Circline bulb the Luxo carries.

Then comes the really fun part... finding a  way to mount the swingarm on my desk/workbench, which has already proven very uncooperative in previous attempts. 

mnem
 

[med6753]

Then comes the really fun part... finding a  way to mount the swingarm on my desk/workbench, which has already proven very uncooperative in previous attempts. 

mnem
 

Simple. Drill hole in bench. Insert.

Not difficult. 

[xrunner]

Simple. Drill hole in bench. Insert.

Not difficult. 

Ugh. Waaaaaaaay too easy for this group. Please re-engineer the solution to incorporate calculations, a mechanical contraption to include 3D printed parts, and CAD drawings. 

[URI]

Simple. Drill hole in bench. Insert.

Not difficult. 

Ugh. Waaaaaaaay too easy for this group. Please re-engineer the solution to incorporate calculations, a mechanical contraption to include 3D printed parts, and CAD drawings.

Mindestens.   

(english: at least)


--
Bye, going to bed now.

[Cerebus]

Ugh. Waaaaaaaay too easy for this group. Please re-engineer the solution to incorporate calculations, a mechanical contraption to include 3D printed parts, and CAD drawings.

No, explosive forming is the only acceptable technique.

[med6753]

Simple for me because I'm not an engineer. Never was, never will be. 

Just a lowly technician. We take the stupid shit engineers dream up and simplify it. 

[tautech]

Simple for me because I'm not an engineer. Never was, never will be. 

Just a lowly technician. We take the stupid shit engineers dream up and simplify it to match the tools at our disposal ! 

[med6753]

Amen! 

[bd139]

An engineer's real job is to over-analyse the problem, consume lots of company lunches, get paid to go on training courses about the problem at hand, have meetings to discuss requirements and eventually a solution suddenly appears out of thin air due to market demand anyway, take full credit for selecting it, then bugger off half way through the implementation 

Edit: minor rant. Fuck LCD modules. I've got a no brand one here which works perfectly in circuit. Use a "decent quality" Matrix Orbital one which is supposedly hd44780 compatible and it's fucking not. I'm wearing the flash out on this AVR futzing with the timing issues 

[med6753]

To be perfectly honest in all my years at IBM the vast majority of engineers I worked with knew their stuff. But like every profession every once in while you ran into one that was dumber than a box of rocks.     

[beanflying]

The truely 'special' Engineers were the top of their class and straight out of Uni 

Such characters should generally be given a Broom to push on a factory floor for six months to actually learn something.