Test Equipment Anonymous (TEA) group therapy thread

[Cubdriver]

Here as promised are the teardown photos showing the display and it might be possible to mount some white LEDs around the edge of the display as it has glass edges exposed and is raised up from the pcb. I'll investigate this a bit more but they would to be switched via switc on the back plate because it is also a portable battery powered device and the LEDs would reduce the operating time if they were on all the time.

Damn!!  They sold you a box of air!  Amazing what they're doing now with them there newfangled 'eye-see' things!  Why, back in the day counters actually had STUFF inside their cases!!   



 

-Pat

[bd139]

That thing has an ozone hole above it 

[Specmaster]

Yep and whats more when that was switched on, it also heat the whole house, even in these freezing conditions that we have currently 

[bd139]

Yep. HP counter owner or cannabis grower - who knows?

[Specmaster]

Thanks for posting the teardown photos. Looks nicely made. Nice to see decent quality GP cells in there too.

I reckon you might be able to get away with backlighting that. Talking of which I came across these the other day looking for a similar solution for a bog standard 4 digit LCD module display (for VFO frequency reporting). I was going to have a button which turned on the backlight for 20 seconds so you could tune: https://uk.rs-online.com/web/p/visible-leds/7173861/

Damn and blast it, you're determined to get me into doing some of that there  SMD stuff arent you 

[Mr. Scram]

By all means but when they say their settings, it probably refers to the settings on Ebay itself that restricts their ability to do it?

I honestly don't know where the problem lies. All I know there's a discrepancy between their messages and the practical situation.

We'll find a solution, though

[Specmaster]

Thanks for posting the teardown photos. Looks nicely made. Nice to see decent quality GP cells in there too.

I reckon you might be able to get away with backlighting that. Talking of which I came across these the other day looking for a similar solution for a bog standard 4 digit LCD module display (for VFO frequency reporting). I was going to have a button which turned on the backlight for 20 seconds so you could tune: https://uk.rs-online.com/web/p/visible-leds/7173861/

Damn and blast it, you're determined to get me into doing some of that there  SMD stuff arent you 

Maybe it could be a suitable test of my new soldering station when it arrives? I'd need to think about this a bit as it would need a pcb and I have never made one from scratch, although I suspect that I could cobble something together using veroboard cut into strips with tracks suitably cut and wire the LEDs in series. Have to pull down the data sheets for those LEDs to see what they draw and what voltage they work at as I only have 5v coming in. I might have to look at a power brick as well, getting complicated now, maybe just hold torch in front of it then 

[mnementh]

They bounce though 

So do my kids, but that doesn't mean I want to stick ugly chunks of rubber on all their corners. 

I still can't find a reason why anyone would need an 8.5 digit meter. Please enlighten me

• playing around with the edge of the envelope
• bragging rights
• so you can use a Weston standard cell as a thermometer
• just because
• you are asking us that? Go and wash your mouth out with soap

I keep my scales numbered for just such occasions...

A funny thought occurred to me, i have four 3.5 digit, three 4.5 digit and two 5.5 digit multimeters.

It seems as if my test equipment is ganging together to tell me i need 6.5 next... 

OK, sounds like a mathematically well-defined buying list. 
So you want to increase your stock by three 3.5 digit, three 4.5 digit, three 5.5 digit, three 6.5 digit, two 7.5 digit multimeters for adding a 8.5 digit multimeter finally..      

That'd break the pyramid and minimize GAS. What you need is something like the following:

                                     8.5
                             7.5            7.5
                     6.5           6.5           6.5
              5.5          5.5            5.5          5.5
       4.5         4.5           4.5           4.5          4.5
3.5         3.5          3.5            3.5          3.5         3.5

And then I can come along with a 1KVA toroidal transformer, and try for the 3.5-3.5 split after almost making the tournament-winning strike. 

Here as promised are the teardown photos showing the display and it might be possible to mount some white LEDs around the edge of the display as it has glass edges exposed and is raised up from the pcb. I'll investigate this a bit more but they would to be switched via switc on the back plate because it is also a portable battery powered device and the LEDs would reduce the operating time if they were on all the time.

Looks to me like a great place to use some 5050 RGB LED strip and a cheap controller. There are Oodles of vendors selling this stuff; should be able to get ~1M of strip and an RF controller for approx US$4.00 or so. Just make sure you get 5V controller and LED strip, not 12V. These modulate 3 PWM channels via ~3A FETs sinked to GND, so the same controllers will usually operate from ~5V up to ~24V DC. The LED Strips come premade with ballast resistors scaled to 5VDC input or 12VDC input. You can cut them to length in groups of 3, so physical sizing is pretty easy.

These controllers are available in all styles; from a simple 3-button non-remote model to IR and RF remotes with up to 40 settings. Cost is typically $1-10 China-Direct, about double that price for equivalent units here in the US, so I'd guess there should be similarly priced local vendors for most regions.


mnem
*Lit as frigg*

[Specmaster]

I really doubt that there is sufficient space between the PCB and the front panel for that strip, I have some here and that is about 8mm wide. I'll have to tear it down again and explore that option as well, soon.

[Mr. Scram]

The side lit option is much more elegant, to be honest.

[Specmaster]

Yes I'm inclined to agree as there is section of the front panel that would allow stray light to escape and give the whole display a sort of halo effect.

[mnementh]

No, you just mount it so the LEDs face the exposed clear edge of the LCD. You can fold the FPC back so it's only ~5mm wide. There's also 3528 RGB strip, but it's not as easy to find in 5V and 50 LED/M density.

Will look like this at max brightness; at med brightness the footlighting effect almost vanishes.



mnem
*Lighter*

[Specmaster]

I was looking at directing the LED's directly onto the edge of the display as light will almost certainly bleed through the front plate if I mount them facing it as a desk lamp held against the front blead through earlier when I tested it earlier while I had it striped down.

[mnementh]

Well looky here... 5V 3528 RGB LED Strip. And you know, no reason in the world you can't use these strip LEDs on the ends if that's your preference. The point is the convenience as they're already assembled with the correct ballast resistors and everything.


mnem
I'm all out of "pithy" right now.

[Mr. Scram]

Well looky here... 5V 3528 RGB LED Strip. And you know, no reason in the world you can't use these strip LEDs on the ends if that's your preference. The point is the convenience as they're already assembled with the correct ballast resistors and everything.


mnem
I'm all out of "pithy" right now.

No reason except that they're intended for front lit purposes in a side lit use case? You'll mostly light the inside of the case and possibly shine through the case.

[mnementh]

Umm... no. You still apply the LEDs so they face directly against the edge of the LCD; look again at the first photo. They work great, as you can see in the pics below. If you're worried about light spilling, you just wrap with a layer of kapton tape, then AL foil, then kapton tape to make a light channel. Or do the same around the inside edges of the bezel.

mnem
This space For Rent.

[bitseeker]

That'd break the pyramid and minimize GAS. What you need is something like the following:

                                     8.5
                             7.5            7.5
                     6.5           6.5           6.5
              5.5          5.5            5.5          5.5
       4.5         4.5           4.5           4.5          4.5
3.5         3.5          3.5            3.5          3.5         3.5

ONLY 21 meters needed. 

Yes, isn't it wonderful? And you don't have to buy them all at once. In neo's case, he just needs to buy a 6.5 right now since he already has the rest of the pyramid. When he's ready to get a 7.5, he just fills the gap in the pyramid with one of each of 6.5, 5.5, 4.5, and 3.5. Finally, when acquiring that beloved 8.5, you round it out with one of each of 7.5, 6.5, 5.5, 4.5, and 3.5.

One small issue with the pyramid idea, my 8400A is in a big server rack chassis, as will my future 8500A. Kinda ruins the pyramid, between that and some odd non standard cases a pyramid is out.

Sounds like you need to build a rack that conforms to the desired shape and replace non-conforming meters to fix the symmetry.

[Mr. Scram]

Sometimes you have to love eBay. Fourteen pictures of the same item, from nearly the same angle. It's undoubtedly well intended, but quite useless if you want to know how that bit looks that's not visible from that exact angle.

A for effort!

[Cubdriver]

That'd break the pyramid and minimize GAS. What you need is something like the following:

                                     8.5
                             7.5            7.5
                     6.5           6.5           6.5
              5.5          5.5            5.5          5.5
       4.5         4.5           4.5           4.5          4.5
3.5         3.5          3.5            3.5          3.5         3.5

ONLY 21 meters needed. 

Yes, isn't it wonderful? And you don't have to buy them all at once. In neo's case, he just needs to buy a 6.5 right now since he already has the rest of the pyramid. When he's ready to get a 7.5, he just fills the gap in the pyramid with one of each of 6.5, 5.5, 4.5, and 3.5. Finally, when acquiring that beloved 8.5, you round it out with one of each of 7.5, 6.5, 5.5, 4.5, and 3.5.

One small issue with the pyramid idea, my 8400A is in a big server rack chassis, as will my future 8500A. Kinda ruins the pyramid, between that and some odd non standard cases a pyramid is out.

Sounds like you need to build a rack that conforms to the desired shape and replace non-conforming meters to fix the symmetry.

Or fill in the gaps with smaller bits of gear - power supplies, for instance:



 

-Pat

[Cubdriver]

Yep. HP counter owner or cannabis grower - who knows?

I don't think the 5245L would do that.  A couple of 522Bs on the other hand...









 

-Pat

[xrunner]

Or fill in the gaps with smaller bits of gear - power supplies, for instance:

I love it - gap fillers! 

[Specmaster]

Nope can't use power supplies , sorry as they are only in this instance single digits 

[neo]

That'd break the pyramid and minimize GAS. What you need is something like the following:

                                     8.5
                             7.5            7.5
                     6.5           6.5           6.5
              5.5          5.5            5.5          5.5
       4.5         4.5           4.5           4.5          4.5
3.5         3.5          3.5            3.5          3.5         3.5

ONLY 21 meters needed. 

Yes, isn't it wonderful? And you don't have to buy them all at once. In neo's case, he just needs to buy a 6.5 right now since he already has the rest of the pyramid. When he's ready to get a 7.5, he just fills the gap in the pyramid with one of each of 6.5, 5.5, 4.5, and 3.5. Finally, when acquiring that beloved 8.5, you round it out with one of each of 7.5, 6.5, 5.5, 4.5, and 3.5.

One small issue with the pyramid idea, my 8400A is in a big server rack chassis, as will my future 8500A. Kinda ruins the pyramid, between that and some odd non standard cases a pyramid is out.

Sounds like you need to build a rack that conforms to the desired shape and replace non-conforming meters to fix the symmetry.

Well the exact problems with symmetry, the Fairchild 7050 is in a special case and i like it, the keithley 177A is too thick to conform as is the 8800A and the 8200A is massive. Then there is rack mount gear to consider.

I just wished it, the 8200A, had switches  I kinda screwed them up trying to fix them.

[Cubdriver]

Yep. HP counter owner or cannabis grower - who knows?

...or 500 series Tek gear owner:





 

-Pat

[Cubdriver]

Nope can't use power supplies , sorry as they are only in this instance single digits 

Not if you stumble upon the right ones!     (Something is off here, but neither has been wrung out yet, so I don't know which)





(apologies for the crappy iPhone pics.)

-Pat