Test Equipment Anonymous (TEA) group therapy thread

[mnementh]

Clearly, the product is designed for use on plastics, particularly the kinds of plastic used on electronic equipment. Therefore, it is your understanding of the product that is at question here. You ASSUME it is full of limonene, therefore you assume it is hazardous to plastics. You ASSUME that the manufacturer has somehow formulated a product for use on plastic without neutralizing it to be a safe product for use on plastic.

I'm not assuming, I'm trusting you to be correct in what you said: "They used to advertise "100% oranges for a natural clean" - which implies a highly significant limonene content in the original formulation (>90% if it was indeed 100% oranges [oil ASSUMED, as juice would be farcical]) and reasonably implies a significant concentration in more recent formulations. As it is, a check of the MSDS shows the current formulation to be 1-5% d-Limonene. Still enough to be a concern if left in contact for a significant time.

I am not aware of any mechanism by which a solvent's solving ability can be "neutralized", let alone doing so and it still contributing an ability to dissolve certain things which is surely the whole point of it being in there in the first place (label glue for instance). I'll readily admit that physical chemistry is not my thing so if you know better then please enlighten me as to the mechanism of this neutralization. I mean that seriously, I'm always more than willing to have my ignorance replaced by knowledge.

FFS man, I'm just saying "be cautious if it's got limonene in". It definitely has, so one should definitely be cautious.

This is one of those cases where empirical evidence obtains. Again, obviously it IS a solvent, so of course use care. But it IS designed for this specific application; unlike IPA which is a much broader spectrum solvent. One has to trust to SOME point that it is reasonably safe to use for that intended purpose.


mnem
Water is a solvent too; if only it were as carefully regulated as alcohol.

[Cerebus]

I'm using the "original" LT1073 boost converter plus a random Central Semi 2n2369 for that job. It worked nicely. However no idea of the actual rise time as I have nothing fast enough to measure it. Also I nicked the LT1073 out to use in another converter so it's not working now anyway. I did buy a 74LVC14 to make another one with but haven't got around to it. Much simpler really.

wanted to try a jw pulser just because it was easy and quick. (and fun)  was very happy with the results.

gotta admit though that this sn74ac14n doodad is perfectly fine for testing random hunks of coax.  it's rise time does not appear to be as fast by my measurements, but it is a whole lot more convenient, and by focusing on the ringing peak it has no trouble resolving 4 inches of coax added to or removed from the end of a longer run. 

https://www.ebay.com/itm/TDR-Time-Domain-Reflectometer-Fast-Clock-Version-Detect-cable-faults-More/152587007700?hash=item2386e4f6d4:g:fKMAAOSwXXxZQqx-:sc:USPSFirstClass!52402!US!-1

Souvacrap... that IS a nifty solution! *Adds to watch list for later* Elegant in its simplicity, pretty hard to eff up. Brilliant!


mnem
Everything is a learning experience.

If people are interested in pre-built solutions it might be germane to point out the boards manufactured by this forum's very own Leo Bodnar - with a confirmed 40ps rise time no less. See this thread:[ur]https://www.eevblog.com/forum/projects/yet-another-fast-edge-pulse-generator/msg1737119/#msg1737119[/url] for details.

[xrunner]

But consider this... due to my extensive EXPERIENCE with the product, I am confident enough in the safety of Goo Gone IN GENERAL that I didn't hesitate to smear it all over the lens of my just-acquired Fluke 189 to make SURE before recommending it to Greg.

I've used Goo Gone extensively in restorations of test equipment and other things and never experienced an issue. Some of the old crusted cal stickers require overnight soaking and I've never seen any damage to underlying plastic.

Yea yea yea here's the disclaimer - everybody be careful and test it ... but it's never caused any issues for me.

[Specmaster]

Clearly, the product is designed for use on plastics, particularly the kinds of plastic used on electronic equipment. Therefore, it is your understanding of the product that is at question here. You ASSUME it is full of limonene, therefore you assume it is hazardous to plastics. You ASSUME that the manufacturer has somehow formulated a product for use on plastic without neutralizing it to be a safe product for use on plastic.

I'm not assuming, I'm trusting you to be correct in what you said: "They used to advertise "100% oranges for a natural clean" - which implies a highly significant limonene content in the original formulation (>90% if it was indeed 100% oranges [oil ASSUMED, as juice would be farcical]) and reasonably implies a significant concentration in more recent formulations. As it is, a check of the MSDS shows the current formulation to be 1-5% d-Limonene. Still enough to be a concern if left in contact for a significant time.

I am not aware of any mechanism by which a solvent's solving ability can be "neutralized", let alone doing so and it still contributing an ability to dissolve certain things which is surely the whole point of it being in there in the first place (label glue for instance). I'll readily admit that physical chemistry is not my thing so if you know better then please enlighten me as to the mechanism of this neutralization. I mean that seriously, I'm always more than willing to have my ignorance replaced by knowledge.

FFS man, I'm just saying "be cautious if it's got limonene in". It definitely has, so one should definitely be cautious.

WD40 carries no warning about plastics and has zero orange juice or extracts of fruit of any kind that I can see BUT it does contain petroleum products so I would still be careful in its use. That said though I have been using it for a long time now and I have not had anything react with it.

I use it sprayed onto a cloth or kitchen towel, apply it and then within a couple of moments wipe it off with a clean cloth etc. You can then if required reapply more WD40 if required in safety. I never let any cleansing agent sit or soak in for longer just incase, better safe than sorry.

[Specmaster]

Haha my 2013 had its 3rd annual test today, passed without even an advisory warning of things to be watched. That set of a wave of expense though, road tax, just paid, next week insurance would have made another hole in my TEA budget were it not for the cull I'm having on older and duplicated gear, thanks to which I have a fat wad waiting for right thing at the right time. I'm like a  coiled spring waiting to pounce on something not sure yet what but when it comes WHAM I'm in. [emoji41][emoji41][emoji41]

I went through a process a few years back of doing some things early so that my MOT, road tax, and insurance all got separated in time. So the MOT was yesterday, tax is October and insurance December. Makes the whole process a little less daunting not having them all pile on top of one another to make for a very expensive month.

Yeah I would have done the same, were it not for the fact that I purchased my old company car towards the end of its lease when I retired. Therefore as road tax is not transferred with sale of a car, and I was no longer covered by company insurance and the fact that leaseing company required it be MOT tested before handing back the car, even though they knew I was going to buy it. So I had no option but to tax and insure at the same and because the sale was completed the following week I now have all 3 bills in the same 4 week period, not good at all. [emoji54][emoji54][emoji54]

[Cerebus]

In other news:

I have finally, after months and months of patient sitting like a vulture on eBay, finally, finally, managed to find a sensible sized (270VA), sensible priced (£25), variac and it just arrived:



Needs a bit of tidying up, and the previous owner/user had it wired for "indicated 270V" = "100% of whatever you've fed in", but that will all soon be sorted. At last, now I can properly torture test PSUs for line regulation.

Edited to add: Just popped the covers off over the actual transformer's rating plate - 270V 2A. So I have double the VA goodness, 540VA instead of the seller's advertised 270VA! Yay!

[xrunner]

In other news:

I have finally, after months and months of patient sitting like a vulture on eBay, finally, finally, managed to find a sensible sized (270VA), sensible priced (£25), variac and it just arrived:

Needs a bit of tidying up, and the previous owner/user had it wired for "indicated 270V" = "100% of whatever you've fed in", but that will all soon be sorted. At last, now I can properly torture test PSUs for line regulation.

That's great and I'm glad you posted that because I've been wanting a variac for a long time - don't know why I've been putting it off. I think I'll go to Ebay right now and buy one. 

[bd139]

Haha my 2013 had its 3rd annual test today, passed without even an advisory warning of things to be watched. That set of a wave of expense though, road tax, just paid, next week insurance would have made another hole in my TEA budget were it not for the cull I'm having on older and duplicated gear, thanks to which I have a fat wad waiting for right thing at the right time. I'm like a  coiled spring waiting to pounce on something not sure yet what but when it comes WHAM I'm in. [emoji41][emoji41][emoji41]

I went through a process a few years back of doing some things early so that my MOT, road tax, and insurance all got separated in time. So the MOT was yesterday, tax is October and insurance December. Makes the whole process a little less daunting not having them all pile on top of one another to make for a very expensive month.

Yeah I would have done the same, were it not for the fact that I purchased my old company car towards the end of its lease when I retired. Therefore as road tax is not transferred with sale of a car, and I was no longer covered by company insurance and the fact that leaseing company required it be MOT tested before handing back the car, even though they knew I was going to buy it. So I had no option but to tax and insure at the same and because the sale was completed the following week I now have all 3 bills in the same 4 week period, not good at all. [emoji54][emoji54][emoji54]

I have (well had) this once a year as well. Tax, MOT, Insurance, gas bill, electricity bill, water bill all land within two weeks of each other. And it's my birthday that month so boo hiss 

As for the cull, getting nowhere. Managed to acquire another scope instead and am hitting a junk fest on Sunday with some notes

[tggzzz]

I'm using the "original" LT1073 boost converter plus a random Central Semi 2n2369 for that job. It worked nicely. However no idea of the actual rise time as I have nothing fast enough to measure it. Also I nicked the LT1073 out to use in another converter so it's not working now anyway. I did buy a 74LVC14 to make another one with but haven't got around to it. Much simpler really.

wanted to try a jw pulser just because it was easy and quick. (and fun)  was very happy with the results.

gotta admit though that this sn74ac14n doodad is perfectly fine for testing random hunks of coax.  it's rise time does not appear to be as fast by my measurements, but it is a whole lot more convenient, and by focusing on the ringing peak it has no trouble resolving 4 inches of coax added to or removed from the end of a longer run. 

I hate to say it, but those waveforms look less than good. Here's the output of the 3*(74lvc1g14+143ohms) shown on a Tek 485 350MHz scope.



I have pictures of someone using it on a 1GHz scope with a similarly smooth risetime of 300ps, but there was a 2m cable which might have affected results.

If I wanted to improve your waveforms, I would make sure the decoupling is top notch. However, with a DIL pack you will inevitably get some ground bounce since the Vcc/Gnd leads inside the IC are pessimal (i.e. longest possible at the corners). Do the back-of-the-envelope calculation of I = 5V/100ohms (50ohm load plus 50ohm source resistance), assume L=10nH per lead (10mm), you can see the dt, so you can calculate the voltage induced in the leads as V= L^di/_dt - it is ~5V for a 1ns risetime, 2.5V for a 2ns risetime etc!

[Specmaster]

Haha my 2013 had its 3rd annual test today, passed without even an advisory warning of things to be watched. That set of a wave of expense though, road tax, just paid, next week insurance would have made another hole in my TEA budget were it not for the cull I'm having on older and duplicated gear, thanks to which I have a fat wad waiting for right thing at the right time. I'm like a  coiled spring waiting to pounce on something not sure yet what but when it comes WHAM I'm in. [emoji41][emoji41][emoji41]

I went through a process a few years back of doing some things early so that my MOT, road tax, and insurance all got separated in time. So the MOT was yesterday, tax is October and insurance December. Makes the whole process a little less daunting not having them all pile on top of one another to make for a very expensive month.

Yeah I would have done the same, were it not for the fact that I purchased my old company car towards the end of its lease when I retired. Therefore as road tax is not transferred with sale of a car, and I was no longer covered by company insurance and the fact that leaseing company required it be MOT tested before handing back the car, even though they knew I was going to buy it. So I had no option but to tax and insure at the same and because the sale was completed the following week I now have all 3 bills in the same 4 week period, not good at all. [emoji54][emoji54][emoji54]

I have (well had) this once a year as well. Tax, MOT, Insurance, gas bill, electricity bill, water bill all land within two weeks of each other. And it's my birthday that month so boo hiss 

As for the cull, getting nowhere. Managed to acquire another scope instead and am hitting a junk fest on Sunday with some notes

Oh dear, I'm selling quite a lot of my items and may be adding more soon while I wait for that killer item to come along. Sounds like a heap of fun in your birthday month [emoji44]

[tggzzz]

As for the cull, getting nowhere. Managed to acquire another scope instead and am hitting a junk fest on Sunday with some notes

Where?

[Specmaster]

In other news:

I have finally, after months and months of patient sitting like a vulture on eBay, finally, finally, managed to find a sensible sized (270VA), sensible priced (£25), variac and it just arrived:



Needs a bit of tidying up, and the previous owner/user had it wired for "indicated 270V" = "100% of whatever you've fed in", but that will all soon be sorted. At last, now I can properly torture test PSUs for line regulation.

Edited to add: Just popped the covers off over the actual transformer's rating plate - 270V 2A. So I have double the VA goodness, 540VA instead of the seller's advertised 270VA! Yay!

I think I have the same variac as that, I paid just £8 for it so again laughing to the bank. Did you mean that the previous owner realigned the knob so that full rotation lined up at 100% on the scale?

[bd139]

As for the cull, getting nowhere. Managed to acquire another scope instead and am hitting a junk fest on Sunday with some notes

Where?

https://www.mkars.org.uk/mkars/rally

Will hit NMOC as well as I get free entry with RSGB membership (will donate anyway)

May walk away with nothing.

Also considering hitting national hamfest in Newark on 28/29 September and staying overnight somewhere.

[Specmaster]

As for the cull, getting nowhere. Managed to acquire another scope instead and am hitting a junk fest on Sunday with some notes

Where?

https://www.mkars.org.uk/mkars/rally

Will hit NMOC as well as I get free entry with RSGB membership (will donate anyway)

May walk away with nothing.

Also considering hitting national hamfest in Newark on 28/29 September and staying overnight somewhere.

Beginning to get withdrawal symptoms and need to jump back in the swim again eh, I might just go MK one but need to get smaller more discrete TEA items that are more capable as well then I don't have to worry about SWMBO as she'll never notice small items anyway 🤣

[bd139]

It's a hamfest. I don't think there's anything small or discrete there at all, especially not most of us 

[Specmaster]

It's a hamfest. I don't think there's anything small or discrete there at all, especially not most of us 

Well that's certainly true for me [emoji6] so are you saying that it's unlikely to be much in the TEA line there then?

[bd139]

No none at all. Honestly 

Going from this photo of 2017 suggests there may be some:



Edit: to note, the average radio ham type here in the UK doesn't know which end of the soldering iron to hold so you have to be careful with what you buy at these lest you get something that has been buggered thoroughly. I remember picking up some stuff in the early 1990s at radio rallies which was to put it bluntly "totally munted". I picked an analogue meter once, I think it was a TMK one, and asked to look inside it quickly to make sure it was ok and no batteries had leaked, which they obliged. It looked like like someone had been at it with the soldering iron they put the Infinity Gauntlet together with.

Edit 2: this usually only applied to things with transistors in. The tube dudes hadn't worked out how to treat stuff gently then. Looking at the stuff at Kempton, there were a few suspect items sitting around still. People have worked out what's bad.

[neo]

(Joplin) Hamfest eve now. Decent amount of cash and tickets in hand and the place, which is massive, will be packed    Besides that the next one, mena, falls exactly on my birthday, hopefully i'll have enough to get a decent amount of TEA goodness. Now taking forecasts for the amount of crap i'll be dragging home. 

[bd139]

Good luck  ... interested to see what you come back with

[nixiefreqq]

I'm using the "original" LT1073 boost converter plus a random Central Semi 2n2369 for that job. It worked nicely. However no idea of the actual rise time as I have nothing fast enough to measure it. Also I nicked the LT1073 out to use in another converter so it's not working now anyway. I did buy a 74LVC14 to make another one with but haven't got around to it. Much simpler really.

wanted to try a jw pulser just because it was easy and quick. (and fun)  was very happy with the results.

gotta admit though that this sn74ac14n doodad is perfectly fine for testing random hunks of coax.  it's rise time does not appear to be as fast by my measurements, but it is a whole lot more convenient, and by focusing on the ringing peak it has no trouble resolving 4 inches of coax added to or removed from the end of a longer run. 

I hate to say it, but those waveforms look less than good. Here's the output of the 3*(74lvc1g14+143ohms) shown on a Tek 485 350MHz scope.



I have pictures of someone using it on a 1GHz scope with a similarly smooth risetime of 300ps, but there was a 2m cable which might have affected results.

If I wanted to improve your waveforms, I would make sure the decoupling is top notch. However, with a DIL pack you will inevitably get some ground bounce since the Vcc/Gnd leads inside the IC are pessimal (i.e. longest possible at the corners). Do the back-of-the-envelope calculation of I = 5V/100ohms (50ohm load plus 50ohm source resistance), assume L=10nH per lead (10mm), you can see the dt, so you can calculate the voltage induced in the leads as V= L^di/_dt - it is ~5V for a 1ns risetime, 2.5V for a 2ns risetime etc!

now that there is nice looking edge.

wouldn't ya' know.  its the story of my life.   am perfectly happy with my toyota and then the guy next door parks a buggati veyron in the driveway.

(but they both get you to the local cheesesteak joint.)

[Specmaster]

No none at all. Honestly 

Going from this photo of 2017 suggests there may be some:



Edit: to note, the average radio ham type here in the UK doesn't know which end of the soldering iron to hold so you have to be careful with what you buy at these lest you get something that has been buggered thoroughly. I remember picking up some stuff in the early 1990s at radio rallies which was to put it bluntly "totally munted". I picked an analogue meter once, I think it was a TMK one, and asked to look inside it quickly to make sure it was ok and no batteries had leaked, which they obliged. It looked like like someone had been at it with the soldering iron they put the Infinity Gauntlet together with.

Edit 2: this usually only applied to things with transistors in. The tube dudes hadn't worked out how to treat stuff gently then. Looking at the stuff at Kempton, there were a few suspect items sitting around still. People have worked out what's bad.

The only things on that table that looks remotely interesting are a few power supplies, but hey, how many do you need? I have 2 (cheap ones admittedly) but seldom use them and there what looks like some phillips CRO's. 

[mtdoc]

I'm using the "original" LT1073 boost converter plus a random Central Semi 2n2369 for that job. It worked nicely. However no idea of the actual rise time as I have nothing fast enough to measure it. Also I nicked the LT1073 out to use in another converter so it's not working now anyway. I did buy a 74LVC14 to make another one with but haven't got around to it. Much simpler really.

wanted to try a jw pulser just because it was easy and quick. (and fun)  was very happy with the results.

gotta admit though that this sn74ac14n doodad is perfectly fine for testing random hunks of coax.  it's rise time does not appear to be as fast by my measurements, but it is a whole lot more convenient, and by focusing on the ringing peak it has no trouble resolving 4 inches of coax added to or removed from the end of a longer run. 

I hate to say it, but those waveforms look less than good. Here's the output of the 3*(74lvc1g14+143ohms) shown on a Tek 485 350MHz scope.



I have pictures of someone using it on a 1GHz scope with a similarly smooth risetime of 300ps, but there was a 2m cable which might have affected results.

If I wanted to improve your waveforms, I would make sure the decoupling is top notch. However, with a DIL pack you will inevitably get some ground bounce since the Vcc/Gnd leads inside the IC are pessimal (i.e. longest possible at the corners). Do the back-of-the-envelope calculation of I = 5V/100ohms (50ohm load plus 50ohm source resistance), assume L=10nH per lead (10mm), you can see the dt, so you can calculate the voltage induced in the leads as V= L^di/_dt - it is ~5V for a 1ns risetime, 2.5V for a 2ns risetime etc!

now that there is nice looking edge.

wouldn't ya' know.  its the story of my life.   am perfectly happy with my toyota and then the guy next door parks a buggati veyron in the driveway.

(but they both get you to the local cheesesteak joint.)

If you haven't seen it, Alan (W2AEW) has a nice video on an easy to build TDR with a reasonably fast and clean edge using a Schmitt trigger:

[mnementh]

I'm using the "original" LT1073 boost converter plus a random Central Semi 2n2369 for that job. It worked nicely. However no idea of the actual rise time as I have nothing fast enough to measure it. Also I nicked the LT1073 out to use in another converter so it's not working now anyway. I did buy a 74LVC14 to make another one with but haven't got around to it. Much simpler really.

wanted to try a jw pulser just because it was easy and quick. (and fun)  was very happy with the results.

gotta admit though that this sn74ac14n doodad is perfectly fine for testing random hunks of coax.  it's rise time does not appear to be as fast by my measurements, but it is a whole lot more convenient, and by focusing on the ringing peak it has no trouble resolving 4 inches of coax added to or removed from the end of a longer run. 

I hate to say it, but those waveforms look less than good. Here's the output of the 3*(74lvc1g14+143ohms) shown on a Tek 485 350MHz scope.



I have pictures of someone using it on a 1GHz scope with a similarly smooth risetime of 300ps, but there was a 2m cable which might have affected results.

If I wanted to improve your waveforms, I would make sure the decoupling is top notch. However, with a DIL pack you will inevitably get some ground bounce since the Vcc/Gnd leads inside the IC are pessimal (i.e. longest possible at the corners). Do the back-of-the-envelope calculation of I = 5V/100ohms (50ohm load plus 50ohm source resistance), assume L=10nH per lead (10mm), you can see the dt, so you can calculate the voltage induced in the leads as V= L^di/_dt - it is ~5V for a 1ns risetime, 2.5V for a 2ns risetime etc!

now that there is nice looking edge.

wouldn't ya' know.  its the story of my life.   am perfectly happy with my toyota and then the guy next door parks a buggati veyron in the driveway.

(but they both get you to the local cheesesteak joint.)

Fuck. Now I have pulse envy. 


mnem
Will this fix it?

[bd139]

The only things on that table that looks remotely interesting are a few power supplies, but hey, how many do you need? I have 2 (cheap ones admittedly) but seldom use them and there what looks like some phillips CRO's.

I need a good 20A 12V supply at the moment so win there possibly.

It varies. When I went to kempton I saw Marconi 2019A £120, several HP SA’s £150, Tek TDS 200MHz £180, Tek analogues including 2465 for £150 each, piles of TTi dual supplies for £75 each all shown working and that was just what was left when I got there. Unfortunately someone had emptied the cash machine and I’d have a hard time explaining the appearance of test gear when I was supposed to be babysitting and nipping out to Sainsbury’s quick, so I snagged a book from RSGB stand and some toroids

[neo]

The only things on that table that looks remotely interesting are a few power supplies, but hey, how many do you need? I have 2 (cheap ones admittedly) but seldom use them and there what looks like some phillips CRO's.

I need a good 20A 12V supply at the moment so win there possibly.

It varies. When I went to kempton I saw Marconi 2019A £120, several HP SA’s £150, Tek TDS 200MHz £180, Tek analogues including 2465 for £150 each, piles of TTi dual supplies for £75 each all shown working and that was just what was left when I got there. Unfortunately someone had emptied the cash machine and I’d have a hard time explaining the appearance of test gear when I was supposed to be babysitting and nipping out to Sainsbury’s quick, so I snagged a book from RSGB stand and some toroids

Funnily enough i have a supply that can do that with one small trick. 6-15 volts at 25 amps, for me to get 20v all i'd need is a car battery. Just a suggestion/possibility. The funny bit is i bought it last year for 2 bucks because the guy didn't want to haul it home. 

edit; small misread, i read 20v at 12A. A car battery by itself could be an option.