Test Equipment Anonymous (TEA) group therapy thread

[bd139]

This is needed to feed the SLAs and equipment for offline power ... I should say 15V @ 20A

Had a couple of power cuts recently that lasted hours so I want some offline capacity.

[factory]

My HP 4260A instrument feet (for my first 6114A lacking original feet) has have reached Erlanger...

impatiently waiting..

Haha, yes. The foot-donor. I can't wait to see what that 4260A can do.

The 4260A is one of the Japanese made Yokogawa HP products, hopefully if it's a late one you won't have to do too much to get good readings from it. I saved this link for an early (around 1966) some time ago, their 4260A apparently had many past their best small electrolytic capacitors (I can't tell, but they look a bit like the Sprague ones) that needed replacing to get it working properly.
http://www.pa4tim.nl/?p=3037

I've had mine for a while, it works OK but I don't know how close to spec it is, also I'd never looked in it until now, mine appears to be from the mid 1970's with mostly OMD & some NCC capacitors. All the circuit boards are fitted upside down, behind a panel under the bottom cover.

It also has neons for the directional indicators & decimal points.

David

[Neomys Sapiens]

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.

One thought on this: an orange oil based cleaner is the recommended means for cleaning/degreasing those multicircuit telephone cables for buried use. I think that they would not take any chances with the preparation of cables, which, in case of the insulation of the stripped wires becoming severely degraded, would have to be replaced at high cost. So I think that this and related solvents might be compatible with some plastics. (wire insulation in this cables should be PVC)

[capt bullshot]

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. 

There's a Delta Elektronika supply on that table. The one that needs 3 phase power and outputs 3kW.

[bd139]

Yeah I saw that. Rack mounted box under the Farnell supplies next to the Telequipment D61A

I rather like those little Farnell supplies. Usually go for a tenner. Really compact and silent. Might nab one if there are any going for my QRP rigs

[tggzzz]

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:

Not having the time to watch the video, I don't see the relevance of it being a gate with a schmitt trigger input. What matters is the current drive available from the output, and the shortness of the leads to minimise the di/dt problems associated with fast transitions.

[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!

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.)

OK, I disinterred the photos using a faster scope. Caution: these were made in a hurry, by someone else, and I didn't have time to check them. There was, IIRC a 1m length of indeterminate 50ohm cable between the device and the scope.

Note that using the traditional rule of thumb tr=0.35/BW leads from 1GHz to 350ps. And a 3.3GV/s slew rate

[Cerebus]

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?

No, it's got four taps (*-30-*-210-*-30-*) and the mains input is currently on the outermost two, when to get the marked 270V at maximum it should be on the first and third (with 240V mains input).

[bd139]

Something is telling me I should buy this https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F401587662809

Not tea but has tubes and is described as death trap

[Specmaster]

Well it has certain elements that you love, 1/Challenge 2/QRP  3/Its cheap  4/ Its local   5/It has tubes and last but least 6/ Its has danger all over it and you laugh in the face of danger 

[GregDunn]

And so, as Fluke Week comes (hopefully) to a close...

I was going over to the south side pawn shop to look at that easy-to-fix-maybe 73 III again, but had to go to band practice first.  Nearby was a shop I hadn't been to in a few months - which had not one but three DMMs.  A 175 (quite a bit more than I paid for the 179 yesterday), a 115 (a few dollars cheaper than the 115 I bought a while back), and a 73 III with its holster and a pair of throwaway probes.  Extremely grubby, but the holster kept the meter from getting dinged up and caked with gunk; the only issue seems to be some scuffing of the protective display cover.  It works great in all modes and tracks the other meters nicely.

The price?  $30.

I'd better quit while I'm ahead.

[mnementh]

Something is telling me I should buy this https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F401587662809

Not tea but has tubes and is described as death trap

What... you're still here? 


mnem
It's only suicide if you win.

[neo]

Well it has certain elements that you love, 1/Challenge 2/QRP  3/Its cheap  4/ Its local   5/It has tubes and last but least 6/ Its has danger all over it and you laugh in the face of danger 

No man can escape death though every man can, in the right circumstances, laugh in the face of it.

[med6753]

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.

I have done the same. Goo Gone is excellent for removing stickers, etc. But you have to use another cleaner, such as Simple Green, to remove the residue it leaves behind.

Cerebus.....lots of good info you presented in ref to citrus based cleaners that I never knew. Specifically this Goo Gone stuff says it is "Surface safe"...whatever that means. It does list some items that it should not be used on such as silk, leather, rubber. But it does not list any restrictions for use on plastics. But of course they cover themselves by saying test on the item first.       

[GregDunn]

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.

I have done the same. Goo Gone is excellent for removing stickers, etc. But you have to use another cleaner, such as Simple Green, to remove the residue it leaves behind.

Cerebus.....lots of good info you presented in ref to citrus based cleaners that I never knew. Specifically this Goo Gone stuff says it is "Surface safe"...whatever that means. It does list some items that it should not be used on such as silk, leather, rubber. But it does not list any restrictions for use on plastics. But of course they cover themselves by saying test on the item first.     

I've tried Goo Gone on both the 179 and the 73 III cases, displays, and holster.  It did a nice job of removing some of the grime and embedded grease as well, and after a second pass with Windex to remove the residue there don't seem to have been any adverse effects.  I did soak the 73 holster in a pan of warm water and sudsy dish soap for a while first; that turned it from dark brown to dark yellow.   

Now when I have a few minutes I'm going to try to polish the display covers to get rid of as much of the scuffing and scratching as I can.  I have some multi-step polish designed for plastics which takes a little patience but should at least improve the appearance a bit.

[bitseeker]

Goo Gone is excellent for removing stickers, etc. But you have to use another cleaner, such as Simple Green, to remove the residue it leaves behind.

Yeah, sometimes it can be pretty resistant to removal, as if you were trading one issue for another. Good stuff for the restoration arsenal, though.

[bitseeker]

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:

Is that made by General Radio? I see Zenith on it, but the style is reminiscent of meterless Gen Rad ones. They go for a pretty penny on eBay. You got a good deal on that even if it's not Gen Rad.

Coincidentally, I got a variac today. It was more expensive than I felt like paying, especially since it was "untested." However, it's a rather rare HP ET-5874. This was only the second one I've seen in the past few years. The last one sold a couple years ago for more than double, so I bit. I couldn't find any docs on it, but an old photo if the interior of one looked like it has either an isolation transformer in line with the variac or the 230V output is just a fixed voltage.

The good thing is that it has a front foot. The bad thing is it doesn't have a rear foot. LOL!

[Cerebus]

Is that made by General Radio? I see Zenith on it, but the style is reminiscent of meterless Gen Rad ones. They go for a pretty penny on eBay. You got a good deal on that even if it's not Gen Rad.

Coincidentally, I got a variac today. It was more expensive than I felt like paying, especially since it was "untested." However, it's a rather rare HP ET-5874. This was only the second one I've seen in the past few years. The last one sold a couple years ago for more than double, so I bit. I couldn't find any docs on it, but an old photo if the interior of one looked like it has either an isolation transformer in line with the variac or the 230V output is just a fixed voltage.

The good thing is that it has a front foot. The bad thing is it doesn't have a rear foot. LOL!

I don't know. In the back of my mind I remember something about a relationship between Zenith and Gen Rad, but I'm not sure. I've had it to bits this evening and the casting on the bottom of the actual transformer has "Made in England" cast into it. The winding is in beautiful nick, I'll try to remember to post some photos tomorrow when I've decent daylight to take them by.

I really like that HP one, I'm beginning to get variac envy.

[mnementh]

In Other News...




My fuses & precision resistors from n2cbu have arrived; Fuses test to spec for resistance as advertised and now the ones I snurched from my Ragu 17B are back where they belong.

It took some jiggery-pokery to get good contact through the baggies, but 100ohm 0.1% resistors read 100.09/100.11ohm, and the 5.315K 0.1% I could get contact with read 5316ohms with the 189. I think that's pretty good. Still awaiting the rest of my parts to make the cheap resistance array, and I'm loathe to take them out of the baggies until I'm ready to build.

mnem
ZZZzzzZZZzzzombie...

[Cubdriver]

Coincidentally, I got a variac today. It was more expensive than I felt like paying, especially since it was "untested." However, it's a rather rare HP ET-5874. This was only the second one I've seen in the past few years. The last one sold a couple years ago for more than double, so I bit. I couldn't find any docs on it, but an old photo if the interior of one looked like it has either an isolation transformer in line with the variac or the 230V output is just a fixed voltage.

The good thing is that it has a front foot. The bad thing is it doesn't have a rear foot. LOL!

Sweet!  I've never seen one of those!  Great score!

-Pat

[bitseeker]

Is that made by General Radio? I see Zenith on it, but the style is reminiscent of meterless Gen Rad ones. They go for a pretty penny on eBay. You got a good deal on that even if it's not Gen Rad.

I don't know. In the back of my mind I remember something about a relationship between Zenith and Gen Rad, but I'm not sure. I've had it to bits this evening and the casting on the bottom of the actual transformer has "Made in England" cast into it. The winding is in beautiful nick, I'll try to remember to post some photos tomorrow when I've decent daylight to take them by.

Looking forward to see that. I'll do the same when mine gets here.

I really like that HP one, I'm beginning to get variac envy.

Oh no! There are so many different ones to collect, if you're not careful, you'll end up with too many, like me.

Coincidentally, I got a variac today. It was more expensive than I felt like paying, especially since it was "untested." However, it's a rather rare HP ET-5874. This was only the second one I've seen in the past few years. The last one sold a couple years ago for more than double, so I bit. I couldn't find any docs on it, but an old photo if the interior of one looked like it has either an isolation transformer in line with the variac or the 230V output is just a fixed voltage.

Sweet!  I've never seen one of those!  Great score!

Thanks. I'll let you know if it works. It looked like the original cal stickers were still in place on the enclosure's screws, so I'm hopeful. If all else fails, I've got some analog meters, a variac without an enclosure, and a toroidal transformer around here to rebuild and enhance the thing.

[Cubdriver]

In Other News...




My fuses & precision resistors from n2cbu have arrived; Fuses test to spec for resistance as advertised and now the ones I snurched from my Ragu 17B are back where they belong.

It took some jiggery-pokery to get good contact through the baggies, but 100ohm 0.1% resistors read 100.09/100.11ohm, and the 5.315K 0.1% I could get contact with read 5316ohms with the 189. I think that's pretty good. Still awaiting the rest of my parts to make the cheap resistance array, and I'm loathe to take them out of the baggies until I'm ready to build.

mnem
ZZZzzzZZZzzzombie...

I got some things from him too, most for no real good reason other than the prices were good and I'll keep them in my spares stock.  The adapters and attenuators will go in my RF goodies box, and I want to try the DC-DC converters for driving nixies.



Incoming QA inspected things and approved, too, so it's decent stuff...


-Pat

<edit - I got some things, not somethings.  Damned space bar!>

[Cubdriver]

Looking forward to see that. I'll do the same when mine gets here.

I really like that HP one, I'm beginning to get variac envy.

Oh no! There are so many different ones to collect, if you're not careful, you'll end up with too many, like me.

I finally stopped bringing them home.  It is handy to have more than one sometimes, though - semi-permanent setups can stay set up, for instance...

Coincidentally, I got a variac today. It was more expensive than I felt like paying, especially since it was "untested." However, it's a rather rare HP ET-5874. This was only the second one I've seen in the past few years. The last one sold a couple years ago for more than double, so I bit. I couldn't find any docs on it, but an old photo if the interior of one looked like it has either an isolation transformer in line with the variac or the 230V output is just a fixed voltage.

Sweet!  I've never seen one of those!  Great score!

Thanks. I'll let you know if it works. It looked like the original cal stickers were still in place on the enclosure's screws, so I'm hopeful. If all else fails, I've got some analog meters, a variac without an enclosure, and a toroidal transformer around here to rebuild and enhance the thing.

Thankfully, there's probably not a whole lot to go wrong in there.  And if it's HP of the vintage it looks like, it's probably fairly bullet resistant.

-Pat

[bitseeker]

Yeah, since there aren't many out there, it reduces the odds that it was in the hands of someone abusive.

[Specmaster]

In Other News...




My fuses & precision resistors from n2cbu have arrived; Fuses test to spec for resistance as advertised and now the ones I snurched from my Ragu 17B are back where they belong.

It took some jiggery-pokery to get good contact through the baggies, but 100ohm 0.1% resistors read 100.09/100.11ohm, and the 5.315K 0.1% I could get contact with read 5316ohms with the 189. I think that's pretty good. Still awaiting the rest of my parts to make the cheap resistance array, and I'm loathe to take them out of the baggies until I'm ready to build.

mnem
ZZZzzzZZZzzzombie...

I got somethings from him too, most for no real good reason other than the prices were good and I'll keep them in my spares stock.  The adapters and attenuators will go in my RF goodies box, and I want to try the DC-DC converters for driving nixies.



Incoming QA inspected things and approved, too, so it's decent stuff...


-Pat

Well if it passes the inspection, it must be good  What is it with cats and things in plastic bags, my 2 cats are the same, have to inspect anything in a plastic bag and they love to lick them all the time