Test Equipment Anonymous (TEA) group therapy thread

[mnementh]

From the "I Guess I'm channeling bd tonight..." Dept:

   

After 2 afternoons spent reverse-engineering the "THX Certified" amplifier in this subwoofer to get it to turn on without the "special speaker", I get it working and discover 3 of the 4 non-bridged outputs are just distorted as hell, even after isolating the final amp ICs from the rest of the tone control & compensation circuitry.  In disgust I throw all the bits back in the speaker box (after yoinking the 15V/4A SMPS board to atone for its sins ) and set it aside.

30 minutes work and I knock this little electron-agitator together out of stuff I have lying around. Okay; technically the 99¢ PAM8403 digital amplifier dev board is one of a handful bought expressly to have "lying around" for "just such an occasion", but I really didn't MEAN to pack it in my single small shoebox bin of essential quadcopter bits. They appear to have just gravitated in there while I was separating out what was going into the trailer for long-term storage.

3W + 3W isn't earth-shattering, and certainly not the sound quality I was hoping for out of that sub & speakers; but it's plenty to hear my Linus videeozz & stream Amazon at sane volumes while I inconvenience electrons in here. 

And yes, this is what my once-glorious marble-countertopped workbench has been reduced to: One toolbox and a Amazon carton over the kitchen table. 

mnem
I SO-O-O miss my MetCal... the T12 OLED station makes me fucking WORK for it.

[0culus]

Still unpacking I suppose?

[mnementh]

Hardly. We are still visitors... tourists. The trailer is in storage stateside until all our paperwork is complete. We arrived here with what we could pack in the back of a Rav4 (plus 3 storage bins on a trailer-hitch fanny-pack).

So much cash outlay just getting here, then all the stuff you need to buy to "startup" a new household... Dishes, cutlery, coffeepot/nukebox/toaster, etc... the first pantry & fridge-full of food... Shit, we spent $350 yesterday to get Parkas & heavy pants for the boi & grrl. At Costco we spent that much just on 2 kids, FFS!

So yeah... there's a reason I'm shopping nonessential shit like this from the Thrift. 

I still got 4 good satellite speakers out of the thing... plus I can always seal up the sub & make it passive; run it from another amp. Maybe shell out the CAD$10 for a TPA3116D2-based 2.1 amp board upgrade. Woohoo!!! 

mnem
Dammit... now I'm thinking about how I need my printer to make the backplate... 

[mansaxel]

Missed out on the Philips counter in-country.

What's your plans for a universal counter? Do you have a checklist of properties it should have?
What about a more decent/modern one like a PM6685?
I have one here replaced by another one with GPIB.   
It has a OEM OCXO option with a little bit flaky trim pot I want to replace before it has to go.
(The trim pot seems to have a resistance-non-continuity just around the point for trimming it exactly to 10MHz.  )

Two reasons are tied; because it is TE and because it (some Philips and by brand migration, early Fluke counters) happens to be made in Sweden!  That's all the TE Enthusiast needs, right?

Further, I'm aiming for a frequency counter that can be used for verifying and calibrating sub-1GHz radio equipment and various time / frequency devices.  I'm a sucker (bigtime) for older well-made equipment that has seen use in an iconic position and now needs a continued sense of purpose.  Some of the challenges in getting workable and trustworthy measurements from older gear make the user appreciate both the level of work required to get us where we are today and the absolute level of achievement science has reached in everyday situations.

[URI]

Missed out on the Philips counter in-country.

What's your plans for a universal counter? Do you have a checklist of properties it should have?
What about a more decent/modern one like a PM6685?
I have one here replaced by another one with GPIB.   
It has a OEM OCXO option with a little bit flaky trim pot I want to replace before it has to go.
(The trim pot seems to have a resistance-non-continuity just around the point for trimming it exactly to 10MHz.  )

Two reasons are tied; because it is TE and because it (some Philips and by brand migration, early Fluke counters) happens to be made in Sweden!  That's all the TE Enthusiast needs, right?

Ok, I got that.

*Looking for sticker of the back of the PM6685*

The sticker on the back of the PM6685 in question says "Made in Sweden"!      

I haven't noticed before.

Aside from that the PM6685 is a well specked and well built universal one channel counter that can be upgraded with a second channel for higher bands in the GHz region. Perhaps you already noticed that there are third party sets for this available, e.g. ebay, that are good for up to 3 GHz, iirc.

Further, I'm aiming for a frequency counter that can be used for verifying and calibrating sub-1GHz radio equipment and various time / frequency devices.  I'm a sucker (bigtime) for older well-made equipment that has seen use in an iconic position and now needs a continued sense of purpose.  Some of the challenges in getting workable and trustworthy measurements from older gear make the user appreciate both the level of work required to get us where we are today and the absolute level of achievement science has reached in everyday situations.

On one hand the PM6685 is already an older unit but still powerful enough for doing tasks with up-to-date requirements, I think.   
Of course it has a 10MHz external reference input, so no barrier against time nuttery. 

[McBryce]

I liked the dio-citor, myself... 

mnem
 

Skipped your morning coffee? That's the standard symbol for a Varicap.

McBryce.

[beanflying]

After yesterdays Blood Bath of injuries I opted for some 'safe' woodworking by Laser. Because Lasers are safer 

Couple of woodworking tools, marking gauge, marking knife and a center finder. Trial fitted and glue up tomorrow time permitting. Marking knife blade is subbed by a ply one until I brave the hacksaw and grinder.

Fusion 360 for the modelling bit.

[beanflying]

Hey @Brumby want to raise the blood pressure of SHMBO 'some more' 

Needs some love but if it was closer I would find a place for it in the toy collection  eBay auction: #193188410543

[bd139]

It's a "deathinator"!

NanoVNA out for delivery today 

[McBryce]

I'd get it just for the looks. Illuminate the oil with blue LEDs and stand it in the corner just to scare people. Unfortunately it would cost a fortune to get it to me

McBryce.

[PA0PBZ]

Illuminate the oil...

Do you think there's oil in there?

[McBryce]

Illuminate the oil...

Do you think there's oil in there?

If there wasn't it would illuminate itself

McBryce.

[beanflying]

Illuminate the oil...

Do you think there's oil in there?

Based on the weight I would say yes. With some TLC it would fit in with my Jacobs Ladder and few bits of HV spark and zap 'educational' toys 

[PA0PBZ]

Illuminate the oil...

Do you think there's oil in there?

If there wasn't it would illuminate itself

McBryce.

Ok, I thought based on the number of resistors it looks like there's less than 1KV between 2 closest points, but yes, 17Kg has to be put somewhere

[med6753]

Fluke 8810A update: It was powered up yesterday in excess of 8 hours and absolutely no drift on any parameter was observed. Which at this point is a little puzzling can't argue with the results. So I powered down the 8810A but left the 8800A and 8050A powered up.

This morning from a cold start the 8810A ref and +18V immediately settled at +7.0010V and +18.065V. The measured voltage to the 9.99691V reference was 9.9971V – 9.9972V. After a half hour warm up was essentially the same. Yesterday it measured 9.9969V – 9.9970V. I don't consider that a significant difference. And it does appear after 1 hour to be decreasing. So I'm going to leave it on all day and see what happens. But so far it looks pretty good and the only thing I did was make damn sure all the calibration parameters were dead on. 

[VK5RC]

Although not strictly test equipment - it certainly is a Boat Anchor.
On the weekend it was our state's biggest buy and sell - lots (well 3)of Yaesu FRG 7s - a lovely receiver.
But a FT101B for AUD 50 with all bits minus the 'finals' was too good to pass by. Cosmetically pretty good, no final tubes but I happened to have a spare pair for my working FT 101E, The dial has the sticking issue and some idiot has burnt out one of the blades in the power connector - so a bit of sleuthing will be required - a bit of fun.
My fingers remain attached at present!

[bd139]

Oh cool. I always wanted one of them. There was a pretty badly wrecked one that went for £25 nearly me a while ago which I did consider.

Edit: it still annoys me that Yaesu call RIT/XIT a clarifier.

[McBryce]

Illuminate the oil...

Do you think there's oil in there?

If there wasn't it would illuminate itself

McBryce.

Ok, I thought based on the number of resistors it looks like there's less than 1KV between 2 closest points, but yes, 17Kg has to be put somewhere

Based on the fact that he says it is in the description: "It is a voltage divider made up of 1% resistors in silicone oil.", I'm pretty sure it is.

McBryce.

[Cerebus]

I'd get it just for the looks. Illuminate the oil with blue LEDs and stand it in the corner just to scare people. Unfortunately it would cost a fortune to get it to me

Na, use some RGB LEDs, drive 'em from a teeny-weeny microcontroller that has an ADC hooked up across the meter and alter the colour with the voltage and introduce some flashing effects once it gets up close to "Igor, increase the power" levels. Maybe add a tidy speaker so that it can say "Nearly there Masthter!" at the same time.

[nixiefreqq]

Ghetto-fab solution no 427c: Lift a leg, insert resistor to shift the "good spot"... 

Looks to me like the morning after with your typical redhead. 

mnem
Still worth it.

No, I'm remembering the bridge as blue. You know which blue  . Although revisiting it on Google Earth says "rusty grey":

awwwwwww.  i can beat all those.

1974.  diane temple.   she broke my heart.

Yes, but did she extract her pound of flesh along with...?




was going for this.   maybe a little too old and too obscure?

[Cerebus]

... our state's biggest buy and sell ...

Is that Aussie colloquial for what's called a "bring and buy sale" here in Blighty? Something along the lines of a jumble sale but where the goods to be sold (usually for some good cause) are brought along and donated on the day by the people who have also come to buy things.

[med6753]

I chose to stay out of yesterday's discussion of scars and stitches because I don't want to rehash in my mind all the nasty injuries I had as a kid with glass, rocks, and deli meat slicers. 

The stories I could tell and the scars to prove it. 

[bd139]

Right toy time!

NanoVNA arrived. Took it to bits of course, mostly to put the case on...



Shielding and battery present!



As provided plus case. I had to cut a couple of bevels inside the case to fit the solder around the shields but fit was excellent otherwise.



I had to work out which load was which but that was fortunately quite easy! I ran through cal and all is good.

First step was to test it against a known good dummy load across HF. So I chucked in SWR mode.



Looks good. I will do further tests later. I've got a couple of crystal filters lying around I want to play with termination on so it'll be a good way of testing it and passband. Then I'll attack the antenna at the weekend!

Thanks to xrunner for drawing attention to this one 

If anyone wants one: £35.99 at https://www.ebay.co.uk/itm/323899986991 ... drop shipped UK.

Case is here: https://www.thingiverse.com/thing:3818979 ... took about 5 hours to print at 0.12mm layer depth on the Ender 3. The provided pen design is shit - don't bother. I'm using a Bic instead

[Specmaster]

From the "I Guess I'm channeling bd tonight..." Dept:

   

After 2 afternoons spent reverse-engineering the "THX Certified" amplifier in this subwoofer to get it to turn on without the "special speaker", I get it working and discover 3 of the 4 non-bridged outputs are just distorted as hell, even after isolating the final amp ICs from the rest of the tone control & compensation circuitry.  In disgust I throw all the bits back in the speaker box (after yoinking the 15V/4A SMPS board to atone for its sins ) and set it aside.

30 minutes work and I knock this little electron-agitator together out of stuff I have lying around. Okay; technically the 99¢ PAM8403 digital amplifier dev board is one of a handful bought expressly to have "lying around" for "just such an occasion", but I really didn't MEAN to pack it in my single small shoebox bin of essential quadcopter bits. They appear to have just gravitated in there while I was separating out what was going into the trailer for long-term storage.

3W + 3W isn't earth-shattering, and certainly not the sound quality I was hoping for out of that sub & speakers; but it's plenty to hear my Linus videeozz & stream Amazon at sane volumes while I inconvenience electrons in here. 

And yes, this is what my once-glorious marble-countertopped workbench has been reduced to: One toolbox and a Amazon carton over the kitchen table. 

mnem
I SO-O-O miss my MetCal... the T12 OLED station makes me fucking WORK for it.

A few years ago I was given a THX certified sound system, I was told that it was a 5.1 system and I was expecting something small like you see in computer shops with the flat panel type of side speakers, instead I was confronted with this beast of a system that weighs over 40lb .



Getting it home and connecting it to my computer took my breathe away with its huge powerfull deep bass and sheer volume, the thing is capable of delivering continously 200W of power, not peak power but 24/7 RMS watts that shakes the doors and windows if you wind the volume up. Watch a movie and have the sound delivered via this on the PC is awesome, it beats the pants of my system for the TV and to think I got it free, even today I pinch myself, never heard anything to match it either, watching movies on it, you get that real deep rumble that makes your stomach tremble just as you get in the cinema.

[shakalnokturn]

Hey @Brumby want to raise the blood pressure of SHMBO 'some more' 

Needs some love but if it was closer I would find a place for it in the toy collection  eBay auction: #193188410543

Wound resistors !