Test Equipment Anonymous (TEA) group therapy thread

[Squarewave]

Quick Hamfest report



1x HP204D £10
1x Farnell TM6 RF voltmeter £15
2x ARRL books to bounce £3
2x loads of trimmers £5

Hard to spend at these things 

*sniffs the air inquisitively*

Why do I smell a DIY RF power meter on the wind...? 

mnem
more power!!! waugh-waugh-waugh!!!

Thought he said no more RF / Ham gear, that rabbit hole had been filled in I thought.

Ham and Rabbit? There's a combo....Ham, egg, rabbit and chips.

[mnementh]

Eff.
I effed up. produced a nice lil short on a 100A 12V rail ...
 
Oh well. I should have been more careful.
The connector has melted. The Fluke 179 has survived. The PCIE extender is a pile of plastic rubble.
The PSU survived.

I found the mistake. My brain effed up.

Been dere, dunnat on my personal gaming rig. I know this pain viscerally. What aboot the MB it was plugged into...? Or was it one of your mining rigs?

mnem
 

[mnementh]

Quick Hamfest report



1x HP204D £10
1x Farnell TM6 RF voltmeter £15
2x ARRL books to bounce £3
2x loads of trimmers £5

Hard to spend at these things 

*sniffs the air inquisitively*

Why do I smell a DIY RF power meter on the wind...? 

mnem
more power!!! waugh-waugh-waugh!!!

Thought he said no more RF / Ham gear, that rabbit hole had been filled in I thought.

Ham and Rabbit? There's a combo....Ham, egg, rabbit and chips.

Yeeeaaahhh... imagine that. This is bd we're talkin' aboot. 

As long as we leave bun-bun out of the recipe, sure - Yummmmm!!! I like them much better as lawn ornaments than food.

mnem

[Zenith]

Quick Hamfest report

1x HP204D £10
1x Farnell TM6 RF voltmeter £15
2x ARRL books to bounce £3
2x loads of trimmers £5

Hard to spend at these things 

Our local Hamfest is coming up soon, & hopefully, this time I will get there early---I usually dilly-dally around, & get there just late enough so that I miss the chance that there may be a really outstanding bargain.
That said, as "I have short arms & long pockets", I am still reluctant to spend much!

The problem is that they often don't put prices on things, so you have to ask. If there's a price on it, people tend to assume that's the price and that's the end of it. Rallies are somewhat different, but generally British people don't like asking and certainly don't like haggling. I don't know how it works in Oz.

On the other hand, the stallholder has often gone there to get rid of stuff, get a few bob for it rather than throw it away, and be happy it's gone to a good home - or at least someone else is the Philestine who strips it for parts and throws the skeleton away.

[bd139]

I always haggle. I got that HP generator down to a tenner.

Just got back. Photo dump coming later. Too hot now 

Did a walk along the coast quickly. Attached actual photo

[mnementh]

mnem
*back out into jitterbug sander hell*

[capt bullshot]

I second that.

In unrelated news, here are the results of my beer crate AA holder print test.

Nice!

Brought this one from a Düsseldorf weekend trip, after killing its original contents it fits crappy power banks ...



Edit: Background set to proper TE context 

[m k]

LR44 inside sleeving from the $2 shop is the simplest fastest fix for the now nearly unobtainium 15V cell.

V74PX / 10LR54 - 15V
Diameter: 16mm
Height: 35mm

LR44 - 1.5V
Diameter: 11.5mm
Height: 5.4mm

LR54 - 1.5V
Diameter: 11.6mm
Height: 3.05mm

LR41 - 1.5V
Diameter: 7.9mm
Height: 3.6mm

I think, the LR54 will fit better than the LR44 which is 2mm too high.

5 3xCR1632 and some change could be more stable emergency solution than the pictured one.

Which is, I think, what's in that hack using a nylok nut...

mnem
 

Why 3?
5xCR2032 was my guess.
Somewhere was that the slot is ~16 mm wide, I think.
On the other hand, I actually hardly ever exchange any cash anymore.
And after 2nd peek the nut can't be that big.

Odd that there seems to be no ready made metal fillings for these cases.
Aluminum bolt and a saw will obviously do it but there are also dud filler AA cells.
(not gun related)

[Cerebus]

well this just ruined my day.

is it OT?   sure is........it said "test kit" right on the box.

I thought you were pregnant for a moment until I looked closer. 

Congratulations! It's a     boy   nixie tube.

[mansaxel]

I always haggle. I got that HP generator down to a tenner.

Just got back. Photo dump coming later. Too hot now 

Did a walk along the coast quickly. Attached actual photo

One knows it's actual because there's a lot of people in it. Postcard photographers avoid that when snapping scenery.

[mansaxel]

In the interest of building something with something I've got, today I did a little breadboard exercise with Ye Olde Opamp, the TL072. It will probably need some magic applied to it before it'll pass 10Mhz. OTOH, I put it in the wrong way around (or, did not look properly for the "1" dot when I inserted wires around it ), giving it a fine 500mA from the 6237, so it might very well be toast. There are more where it came from.

A Mouser BOM is forming around the TDS 520. Found all the RIFAS. Some of the SMD caps have greasy circles around them, so leakage is apparent. I'm pondering removal methods;

• Solder tweezers. Not a thing I've got, and I'd need to get a full station to drive them. Limited usage beyond recapping SMD.
• Hot air. Also would need to go on the shopping list. Can literally cost anything. But capable of doing more.
• The Carlson trick of cutting the Al part off the seat, and then going down towards the board. I've got all I need for this. And, it does not look as crazy "rip'em off like they wanna experience pain" as it's sometimes described. (trick apparently is to cut of the bucket first, and then work down until there's only easily (individually) desoldered legs left on the pads.) 

This, also, is not investment season. Vacation was impressingly expensive, and everything else is too.

[capt bullshot]

In the interest of building something with something I've got, today I did a little breadboard exercise with Ye Olde Opamp, the TL072. It will probably need some magic applied to it before it'll pass 10Mhz. OTOH, I put it in the wrong way around (or, did not look properly for the "1" dot when I inserted wires around it ), giving it a fine 500mA from the 6237, so it might very well be toast. There are more where it came from.

TL072 has GBW of 3MHz, so with some luck it'll put out 10MHz at about one third of the input amplitude ...

[Cerebus]

One knows it's actual because there's a lot of people in it. Postcard photographers avoid that when snapping scenery.

Back in the day, photographers would trudge out before dawn to be ready and set up for when the light was right to get a people free photo of places like that. Nowadays, of course, there is Photoshop.

Some photographers preferred a single lone figure in shot, both for scale and arty wistfulness. That type's poor bloody assistant would hear something like this: "Right, the light's almost right. You see that point there [indicates somewhere 1/2 a mile distant]. Go and stand on the edge of the cliff, facing the sea and try and look windswept and interesting. Run! We're going to lose the light! ... Run faster!".

[Zenith]

I always haggle. I got that HP generator down to a tenner.

Just got back. Photo dump coming later. Too hot now 

Did a walk along the coast quickly. Attached actual photo

I don't always haggle. If it's a fiver and I think it's worth it, I just hand over the bank note.

I was at FRARS and had a good chat with tggzzz. He said you were there with your daughter. I saw a miserable old git walking round with lovely young woman, so I assume that was you.

I picked up a few things to help while away the long winter months, including an HP1703 scope complete with manual for a tenner. Now why I bought that, I don't quite know. Some of the knobs look as if they might be replacements for the ones on the HP8640A, which are falling to bits.

No items on the most wanted list, but a few tempting things I was able to resist and a few things too cheap to resist.

There were three HP427 power meters for £15 each. I think they were the same ones as at Newbury. They were discussed on here a time back. I wasn't interested, but I have an idea the bloke would have parted with all three for £25. That's a few useful spares territory.

FRARS seems to be one of the better rallies and I wish I'd gone there before.

[bd139]

First item. HP 204D. Firstly it works perfectly. Even the calibration is good  . But it's coated in nicotine and tar  . To all the smokers: you disgust me! 

As obtained for £10.



Quick internal inspection revealed that it is incredibly difficult to get into. The only window into its guts:



First round of cleaning. These are beige not grey for reference so it's not that bad.



Sides being worked on with Dettol and microfibre cloth



Run out of energy now - will resume later on the BROKEN Farnell TM6 RF voltmeter (spoiler: the sensor head is duff but easily repairable)

I was at FRARS and had a good chat with tggzzz. He said you were there with your daughter. I saw a miserable old git walking round with lovely young woman, so I assume that was you.

Yeah that was me and her probably . Had a hat and sunglasses on.

[Cerebus]

In the interest of building something with something I've got, today I did a little breadboard exercise with Ye Olde Opamp, the TL072. It will probably need some magic applied to it before it'll pass 10Mhz. OTOH, I put it in the wrong way around (or, did not look properly for the "1" dot when I inserted wires around it ), giving it a fine 500mA from the 6237, so it might very well be toast. There are more where it came from.

TL072 has GBW of 3MHz, so with some luck it'll put out 10MHz at about one third of the input amplitude ...

Personal goto for that kind of territory: ADA 4627 (16MHz min GBP, 40V/us, 6.1 nV/sqrt(Hz)@1kHz also low 1/f noise 16.5 nV/sqrt(Hz) @ 10 Hz) quite expensive circa £4-5 but worth it.

[Squarewave]

First item. HP 204D. Firstly it works perfectly. Even the calibration is good  . But it's coated in nicotine and tar  . To all the smokers: you disgust me! 

As obtained for £10.



Quick internal inspection revealed that it is incredibly difficult to get into. The only window into its guts:

[img width-500]https://imgur.com/DMWLH3R.jpg[/img]

First round of cleaning. These are beige not grey for reference so it's not that bad.



Sides being worked on with Dettol and microfibre cloth



Run out of energy now - will resume later on the BROKEN Farnell TM6 RF voltmeter (spoiler: the sensor head is duff but easily repairable)

I was at FRARS and had a good chat with tggzzz. He said you were there with your daughter. I saw a miserable old git walking round with lovely young woman, so I assume that was you.

Yeah that was me and her probably . Had a hat and sunglasses on.

£10 and fully working, that's quite a smoking hot deal.

[Cerebus]

£10 and fully working, that's quite a smoking hot deal.

  Groan.

Anders, are you sockpuppeting us? 

[Squarewave]

£10 and fully working, that's quite a smoking hot deal.

  Groan.

Anders, are you sockpuppeting us? 

Am I what?

[Cubdriver]

First item. HP 204D. Firstly it works perfectly. Even the calibration is good  . But it's coated in nicotine and tar  . To all the smokers: you disgust me! 

As obtained for £10.



Sides being worked on with Dettol and microfibre cloth



Run out of energy now - will resume later on the BROKEN Farnell TM6 RF voltmeter (spoiler: the sensor head is duff but easily repairable)

Wow!  I’m surprised the poor thing doesn’t have cancer!  I’d hate to see the inside of the former owner's lungs!  Yeek!!  (Damned good thing it doesn’t have a cooling fan - imagine the innards if that was the case!)

-Pat

[Specmaster]

Hey, there is yet hope for eBay, well at least hope for some sellers on eBay. Remember earlier in the week there was a post about a Peak DCA50e but the item was in fact a ESR60, well cop this.

https://www.ebay.co.uk/itm/165623099264

[Squarewave]

First item. HP 204D. Firstly it works perfectly. Even the calibration is good  . But it's coated in nicotine and tar  . To all the smokers: you disgust me! 

As obtained for £10.



Sides being worked on with Dettol and microfibre cloth



Run out of energy now - will resume later on the BROKEN Farnell TM6 RF voltmeter (spoiler: the sensor head is duff but easily repairable)

Wow!  I’m surprised the poor thing doesn’t have cancer!  I’d hate to see the inside of the former owner's lungs!  Yeek!!  (Damned good thing it doesn’t have a cooling fan - imagine the innards if that was the case!)

-Pat

Goodness, the former owners lungs would have been through a pretty rough cycle.

[AnalogueLove1867]

Wow!  I’m surprised the poor thing doesn’t have cancer!  I’d hate to see the inside of the former owner's lungs!  Yeek!!  (Damned good thing it doesn’t have a cooling fan - imagine the innards if that was the case!)

-Pat

He might be one of those genetic freaks that smoke from 15 to 90 with no cancer or breathing issues only to die in their sleep from a massive stroke.
Just like my uncle Sindall. Always had a soft spot for him. Super happy, outgoing guy whos only fault was in chain smoking unfiltered rollups every day and smelling like mouldy leather.
 Had a spitoon and everything lol. Would have fit in the cast of a western cowboy movie perfectly.

[mnementh]

LR44 inside sleeving from the $2 shop is the simplest fastest fix for the now nearly unobtainium 15V cell.

V74PX / 10LR54 - 15V
Diameter: 16mm
Height: 35mm

LR44 - 1.5V
Diameter: 11.5mm
Height: 5.4mm

LR54 - 1.5V
Diameter: 11.6mm
Height: 3.05mm

LR41 - 1.5V
Diameter: 7.9mm
Height: 3.6mm

I think, the LR54 will fit better than the LR44 which is 2mm too high.

5 3xCR1632 and some change could be more stable emergency solution than the pictured one.

Which is, I think, what's in that hack using a nylok nut...

mnem
 

Why 3?
5xCR2032 was my guess.
Somewhere was that the slot is ~16 mm wide, I think.
On the other hand, I actually hardly ever exchange any cash anymore.
And after 2nd peek the nut can't be that big.

Odd that there seems to be no ready made metal fillings for these cases.
Aluminum bolt and a saw will obviously do it but there are also dud filler AA cells.
(not gun related)

Because... evidently I've been snorting a little too much shellac dust, or maybe 6 hours wrangling a jitterbug sander has shaken the contents of my skull a wee bit more than is "safe"... and for some unknown reason I was thinking 9V, not 15V power source.

mnem
*takes a few pills and horks up half a lungful*

[bd139]

Now for the rest of the crap.

The Farnell TM6 was listed as TESTED (yeah right!) but for £15 I was expecting to walk away with a meter movement and a bunch of parts to be honest. It's a 50KHz to 1.5GHz rated RF millivoltmeter which is good down to -50dBm and up to +20dBm apparently. Not bad!

I consulted the service manual in the middle of the field (smartphones FTW) and figured it was possible to fix it if it was indeed knackered so I thought what the hell and snapped it up for the asking price. It actually sort of works i.e. it reads something. But when throwing the roughly correct Marconi 2022E into it something was clearly amiss. All of the readings are low. After a few minutes of poking around this appears to be related to the probe interface. After cracking that open I found the culprit: the series resistor wasn't actually still soldered to the BNC port. Unfortunately this means that there is basically a very tiny capacitor in series with the probe tip. Bending the resistor around makes it work with some credible readings however the slug that you're supposed to solder it to is stuck down the end of the probe tube. I got bored here and decided to leave it for another day as my hands and my eyeballs have given up after all that driving today. Plus the HP is more interesting 

Anyway some photos. Outside:



Top - power supply and meter calibration circuitry:



Front end, chopper amplifier and RF front end calibration:



And finally the really interesting bit: the optical chopper. This uses LEDs unlike similar era HP stuff. Must have cost a fortune at the time as the chopper oscillator is driven via a metal can 741 and the LEDs are gold cased ones from the dark ages. Very sexy.



Ignoring the two ARRL books I snagged, only to sell, I did pick up a bunch of parts to use in projects. I picture says a thousand words so here's a fiver of parts. I'm happy with that



Anyway both TE items entered the disinfect and repair queue now which will resume after I've moved.