Test Equipment Anonymous (TEA) group therapy thread

[Specmaster]

Glad to hear that also got yourself a minter as well 

[Cerebus]

It arrived, it’s in mint condition and it works although the batteries are flat. Will order a DC jack and stuff it on the power supply to charge.   

Now going out

May the Lord grant peace and rest to our dear departed, BD139's credit card. 

[Specmaster]

It arrived, it’s in mint condition and it works although the batteries are flat. Will order a DC jack and stuff it on the power supply to charge.   

Now going out

May the Lord grant peace and rest to our dear departed, BD139's credit card. 

I'll second that because its bound to get a real bashing tonight for certain and TEA will have to be put on the back burner in favor of mulled wine and other seasonal
offerings if Mrs bd139 has anything to do with it.

[mnementh]

Suppose I had better chase up manuals, circuit diagrams and such for a HP 5381A  counter 

Lucky I have a couple of nice German Polytron OCXO oscillators 'laying around' to install. This is WHY WE BUY STUFF just in case

 

It is much better to have it and not need it, than to need it and not have it.

-Pat

Yeah... this is how I wound up with a garage full of boxes stacked 6 feet high full of stuff I bought "Just in case I need it" and "For this project bouncing around the back of my head".

I have TEAS, only in a much BROADER range of disciplines including auto repair/customizing, general Electronics tinkery, Computer repair & IT Service (my actual job right now), metal fab/welding, and recently hobby woodworking which started with finding a huge 10" table saw on the curb, then a couple of "fixable" routers and grew to include drum sanders and scrollsaws. 

Oh, and then there's my MAIN hobby... RC aircraft.

Then when it comes time to put up the Christmas tree, EVERYTHING that gets moved to make room winds up in my office/workbench area and I can barely lean back in my chair at the bench.

And the worst part is... at least half the time, when I DO decide to get into one of those "projects bouncing around the back of my head" I either wind up putting it off or worse, buying new components online due to the assache of actually GETTING TO the components I know I have... 

I think the first thing they should do is to update the display, I don't think unlit LCD cuts it anymore. How many workshops have really good lighting levels behind you? Most of them have task lighting above the bench which if your test gear is on the bench means trouble reading the displays. [emoji21]

LCD displays are cheap, super low power, robust and have great longevity. I don't know where you'd want to go, but most other technologies are far inferior. I know those TFT screens look sweet and sexy, but you can bet they won't last as long as LCD or LED displays.

I've actually intentionally looked for LCD or LED displays for most my devices. VFD is good too and looks amazing, though it's more susceptible to wear.

I know I'm going to get a lot of flakk for this because of the inherent longevity issues, but I really wish they'd make larger OLEDs in standardized formats like they do matrix LCDs. I mean they do, but they're ridiculously expensive because the push is always towards higher pixel density right now. I think a nice 80-100PPI OLED with SPI or even I²C bus in various square and wide formats as matrix LCDs are made would be a great idea, and honestly, they're the only display tech I like almost as much as VFD. If they were made as a standardized commodity item like matrix LCDs or even a package like 8-segment LEDs for stacking to size, it would be easy to find suitable replacements even 20 year later, just as it is now with matrix LCDs and 8-segment LEDs.

I'm a compulsive obsessive cleaner so clutter does my head in. This helps 

The lack of space here means I absolutely cannot afford to be allergic to clutter. It simply won't fly.

1000x this. Don't get me wrong... every once in a while I hoe it all out; you HAVE TO. But "organized chaos" is the rule of the day on my bench half the time. That I'm there. Working. When I don't have the door closed. And my wife might be home. 

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.

Further investigation of the counter looks like it will be very difficult to provide some lighting to the screen, especially using LED tape as you did. I tried it last night by laying a stretch of the tape across the top of the gap between the front plate and the pcb and the LCD screen is very close to this edge, effect on the screen, nil but plenty of light spill to edges of the bezel.

Unlike your RC module, the counter does not have a secondary window, the LCD is stepped so it fits into the bezel and finishes almost flush with the front panel. This leaves the thinnest of open glass edges to capture the light and channel it through the LCD panel itself. Also when I presented the section of LEDs to the screen in the region of the counting section of the PCB, the counter sprung into life and started counting. This shows that area is very sensitive to spurious signals but that might have been because the LEDs were powered from a wall wart, maybe better smoothing would prevent it. Total gap between front plate and the PCB is 4mm so there is not a lot of space to play with either.

Hmmm... if you were powering the light from an RGB controller, multiple PWM channels would certainly generate some noise the counter could pick up.

It sucks that this display is flush/recessed mount; sounds like your only other option would be to make a diffuser from scratch to go behind the LCD, and this would only work if is is NOT one of those with an opaque reflector. Most are at least somewhat translucent, though.

What are the dimensions of the LCD, and how much gap is there between it and the PCB behind it? I may know of something ready-made that could be cut to fit.


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

[Mr. Scram]

I agree that OLED could and should be amazing if the technology evolved a little further. Unfortunately, we're still stuck in the period that the technology is expensive and the longevity isn't anywhere near what it should be.

[Specmaster]

Further investigation of the counter looks like it will be very difficult to provide some lighting to the screen, especially using LED tape as you did. I tried it last night by laying a stretch of the tape across the top of the gap between the front plate and the pcb and the LCD screen is very close to this edge, effect on the screen, nil but plenty of light spill to edges of the bezel.

Unlike your RC module, the counter does not have a secondary window, the LCD is stepped so it fits into the bezel and finishes almost flush with the front panel. This leaves the thinnest of open glass edges to capture the light and channel it through the LCD panel itself. Also when I presented the section of LEDs to the screen in the region of the counting section of the PCB, the counter sprung into life and started counting. This shows that area is very sensitive to spurious signals but that might have been because the LEDs were powered from a wall wart, maybe better smoothing would prevent it. Total gap between front plate and the PCB is 4mm so there is not a lot of space to play with either.

Hmmm... if you were powering the light from an RGB controller, multiple PWM channels would certainly generate some noise the counter could pick up.

It sucks that this display is flush/recessed mount; sounds like your only other option would be to make a diffuser from scratch to go behind the LCD, and this would only work if is is NOT one of those with an opaque reflector. Most are at least somewhat translucent, though.

What are the dimensions of the LCD, and how much gap is there between it and the PCB behind it? I may know of something ready-made that could be cut to fit.


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

The size of the LCD is about 103.5mm by 30mm and the space between it and the pcb is 3mm. There are a couple of holes in the pcb directly behind the display and I have shone a light through and it does light up part of the display very dimly and looks milky.

[Mr. Scram]

See, it pays to have two or more of everything. The signal from my AWG suddenly didn't resemble what it should. A very slow square wave looked like pulses with sloping back end and a triangle wave looked like shark fins. Faster square waves had downsloping tops. After hooking up the Chinese signal generator I found that one to display the same behaviour. It must be the oscilloscope then. I couldn't work out what the problem was, but a quick factory reset fixed it.

Does anyone want to hazard a guess what setting changes the shape of signals in such a way? It's a 50 MHz DSO, nothing too fancy. It wasn't the math function or the acquisition modes.

[bd139]

Sounds like a programming error to me.

Back again. Survived!

Got TF930 plugged into the computer. Currently hacking the FTDI driver for OSX so it recognises it and I can start talking to it. Then I'm going to measure VFO drift overnight

Liking it so far.

[HalFET]

BW limit, external clock reference, couple of possible options

Got a 750 EUR bonus because one of my patents was granted, wooohooo. Now to buy something

[Mr. Scram]

BW limit, external clock reference, couple of possible options

Got a 750 EUR bonus because one of my patents was granted, wooohooo. Now to buy something

Congratulations. That must be a good feeling, regardless of the actual patent.

[Specmaster]

Sounds like a programming error to me.

Back again. Survived!

Got TF930 plugged into the computer. Currently hacking the FTDI driver for OSX so it recognises it and I can start talking to it. Then I'm going to measure VFO drift overnight

Liking it so far.

You seem to have got away lightly there then, had visions of the credit card needing CPR after the pounding we predicted.

The TF930 does indeed seem like a nice piece of kit, shame about its housing though. The Velleman turns out to be a Mastech 6100 rebadged but for the lower frequencies seems to be pretty near to perfect by all accounts for the ranges that I work in.

[Mr. Scram]

Found it. The channel was AC coupled, instead of DC. At higher frequencies, the coupling doesn't change the wave shape too much, but at the low frequencies I was looking at, the coupling capacitor changes the wave shapes significantly.

I thought the signal changes looked like there was a capacitor messing with it, but hadn't quite thought of the scope coupling. In hindsight it's pretty obvious.

[HalFET]

Found it. The channel was AC coupled, instead of DC. At higher frequencies, the coupling doesn't change the wave shape too much, but at the low frequencies I was looking at, the coupling capacitor changes the wave shapes significantly.

I thought the signal changes looked like there was a capacitor messing with it, but hadn't quite thought of the scope coupling. In hindsight it's pretty obvious.

BW limit, external clock reference, couple of possible options

Got a 750 EUR bonus because one of my patents was granted, wooohooo. Now to buy something

Congratulations. That must be a good feeling, regardless of the actual patent.

Yeah, because it's completely useless and extremely easy to bypass

[Specmaster]

Been tracking my goods from Aliex and good news, its in the air somewhere on its way to me here, either that or someones using it as a football for a game of (Keeping it Upsee) 

[bd139]

It’s with the carriers called Wun Slung Throw.

[Specmaster]

It’s with the carriers called Wun Slung Throw.

Someones kicked it out of play then tsk tsk.

[neo]

I think i was misinterpreted, but only because i wasn't clear. I have an annual budget of 2K. Yes, that's true, however, it is $160 a month only and i can't just spend it i have to bother coming up with a good reason.

If i go over $160 a month or 2K a year then this becomes me 

Kind of puts a damper on big purchases

Edit: Well there is one amendment to this, any income i generate is mine to spend as i will. I just don't have any income.

[Specmaster]

I think i was misinterpreted, but only because i wasn't clear. I have an annual budget of 2K. Yes, that's true, however, it is $160 a month only and i can't just spend it i have to bother coming up with a good reason.

If i go over $160 a month or 2K a year then this becomes me 

Kind of puts a damper on big purchases

Edit: Well there is one amendment to this, any income i generate is mine to spend as i will. I just don'th have any income.

No I don't thing you were at all, I for one would gladly settle for 160 per month  with 160 a month I could amass a reasonable haul in a year I know.

[bd139]

I would as well. I have to generate the income myself entirely and reliably or I'm up shit creek. Zero interest credit card is the only reason I got new stuff and I worked stupid hard to pay it off. If I saved money it'd get spent before I have saved up enough to buy anything nice.

On the subject of TEA again, I've (a) taken the TF930 to bits and inspected it, (b) checked it out - all good, (c) set up a test rig for what I wanted to test which was using it for long term VFO drift measurement and (d) written a program to grab the frequency every 10 seconds and write it to a file with the unix time stamp.

So good points: doesn't weigh a lot, intuitive, sensitive, works brilliantly, easy to drive from software, doesn't use a lot of power (I'm powering it from PC USB port).
Bad points: uses custom VID and PID for the FTDI chip and I can't work out how to make macOS behave with that (so I had to use the spare windows laptop), display isn't great in low light but I can live with that.

Overall: bargain 

Doing its thing, with it's fellow power supply:

[bd139]

Before I forget, SMM attached. No schematics I'm afraid.

[neo]

I think i was misinterpreted, but only because i wasn't clear. I have an annual budget of 2K. Yes, that's true, however, it is $160 a month only and i can't just spend it i have to bother coming up with a good reason.

If i go over $160 a month or 2K a year then this becomes me 

Kind of puts a damper on big purchases

Edit: Well there is one amendment to this, any income i generate is mine to spend as i will. I just don'th have any income.

No I don't thing you were at all, I for one would gladly settle for 160 per month  with 160 a month I could amass a reasonable haul in a year I know.

In the past year,
Heathkit ID-22
Fluke 8400A
Fluke 8400A loaded with options
Heathkit 0-12
Hickok 209A newer and working
Tek 7704
Fluke 8200A
Fluke 8050A
Keithley 177
Hickok 209A
B+K Precision 1801
1% 0-99.9 ohm decade resistance box
Fluke 8800A
HP 5340A loaded with options
Metcal STSS-02 and new handle
Fairchild 7050A


OK you have a point... quite a haul for a year but quite different when your building a lab from scratch i think...

Either ways things are going to go much slower now because i'm running out of justification for cheap items.

[Specmaster]

Yep, you're not wrong there, I think it really only has the one weakness for most people, the case is crap, display in good lighting is not an issue but as you said in low light its so good. Does the job perfectly and the controls are nicely laid and intuitive as well, and has a 3 way power option which really good, nice and light so is ideal for portability and with the usb for power option it means that cable clutter is kept to a minimum even when interfacing with a computer for data logging etc. If you really needed all of those options then it would be a great deal even at its full retail price but at the prices we paid, its an outstanding bargain.

[bd139]

The case is indeed crap. Took me 10 minutes to work out how to open it as well.

[Mr. Scram]

I don't want to jinx it, but it looks like my TF930 is going to work out after all. I was a bit cheeky and added the shop's address to my shipping addresses, allowing me to put in a bid despite the limitations imposed. Today I got a message that they assume I don't want to gift them a unit and that they'll properly invoice me if I provide the correct details.

I'm glad they're good sports!

[Specmaster]

The case is indeed crap. Took me 10 minutes to work out how to open it as well.

I discovered the way in as soon as I tried to unscrew the front feet and it came away in my hand. A neat method but not reassuringly strong, and should you lose one, what then?