Test Equipment Anonymous (TEA) group therapy thread

[djos]

It's pretty basic, but hey I needed a logic probe, so I bought a kit - should look like this when assembled: 



I could have bought a cheap Chinese pre-built one, but I couldn't wait 4 weeks for it.

EDIT: the design is from Silicon Chip magazine.

http://archive.siliconchip.com.au/cms/A_102204/article.html

[Cerebus]

It found a couple of monster HP supplies this evening but they are too damn big and heavy to justify purchasing. I got the tape measure out and checked 

I keep having the same problem. "Ooo! Shiny HP power supply!", "Oh, monster power supply.  ". It takes long enough to persuade myself that I do need to drag all 32lb of that HP6002 off of the shelf for the thing I'm working on.  Poor bugger spends more time as a car battery charger than it does as a lab supply - that's what you get for being CC/CV and having a 10A output.

Talking of heavy, you'll be pleased to note that I took one of your anecdotes as advice. I had an in on a monster variac for a bargain price (15A ~3600VA) and declined once I recalled your words on similar and realised that it might spend too long in the cupboard and too little time on the bench on the "too much fuss to get the heavy bugger out" basis.

[Specmaster]

It found a couple of monster HP supplies this evening but they are too damn big and heavy to justify purchasing. I got the tape measure out and checked 

I keep having the same problem. "Ooo! Shiny HP power supply!", "Oh, monster power supply.  ". It takes long enough to persuade myself that I do need to drag all 32lb of that HP6002 off of the shelf for the thing I'm working on.  Poor bugger spends more time as a car battery charger than it does as a lab supply - that's what you get for being CC/CV and having a 10A output.

Talking of heavy, you'll be pleased to note that I took one of your anecdotes as advice. I had an in on a monster variac for a bargain price (15A ~3600VA) and declined once I recalled your words on similar and realised that it might spend too long in the cupboard and too little time on the bench on the "too much fuss to get the heavy bugger out" basis.

Yep, I quite agree, I find that a 500VA suits my needs, I have a 500VA isolation transformer as well, never needed anything larger so far.

[bitseeker]

Hers are just a few of my better photos from the Fly Navy airshow at Old Warden recently If anyone wants a high res version for a wallpaper etc, PM me with your personal email address and I'll gladly send one to you.

Very cool, Spec! Always a nice diversion from the regular programming.

[tggzzz]

It found a couple of monster HP supplies this evening but they are too damn big and heavy to justify purchasing. I got the tape measure out and checked 

I keep having the same problem. "Ooo! Shiny HP power supply!", "Oh, monster power supply.  ". It takes long enough to persuade myself that I do need to drag all 32lb of that HP6002 off of the shelf for the thing I'm working on.  Poor bugger spends more time as a car battery charger than it does as a lab supply - that's what you get for being CC/CV and having a 10A output.

Talking of heavy, you'll be pleased to note that I took one of your anecdotes as advice. I had an in on a monster variac for a bargain price (15A ~3600VA) and declined once I recalled your words on similar and realised that it might spend too long in the cupboard and too little time on the bench on the "too much fuss to get the heavy bugger out" basis.

One problem with high current power supplies is that you ought to have the necessary equipment for the extraction of gaseous copper. Sooner or later you'll need it.

[bd139]

Some good points there. The thing is I’ve got this tiny little box which is my comms supply. It weighs about 800g and quite happily pumps out 30A without even getting warm. Switchers FTW. The feed for the radio uses stranded wire about 4mm across. It’s like rope.  Looking at the HP supply, one thing that put me off is the refurb cost as well. The main filter cap in it is 34,000uF at 40V with an appropriately high ripple current. Equivalent part now is £53+VAT. Definitely quieter than the switcher but that has a cheat control (noise offset) which allows you to shift the switching harmonics out of the pass band. Plus a huge ferrite ring.

I actually gave my “scariac” away a few days back to a member of the local amateur radio club so he can repair his boat anchors. He has more space than me as his wife left him   . Has a workshop and parts stock that would put anyone to shame. Tried to get him to join here but the computer is the devil as far as he is concerned.

The female of the species is quite common in amateur radio circles. In fact the first radio amateur I ever met in the early 80s (I don’t classify my father’s CB escapades as official) was. She also showed me how to make my own fireworks 

[mnementh]

Nice work. Some good photos there. Professional quality.

@mnementh: can’t go wrong with anything thinkpad on it from experience. Monitors I’ve never had any problems with. I’ve had this thinkvision one for about 3 years and it was 3 years old when I got it. No dead pixels, nice bright panel. Had a duff cap in it a year ago and that was a £0.50 fix.  If you go for LED backlit ones with 1000:1 contrast they seem to live longer. The thinkvision ones are also terribly over engineered compared to most brands. Can’t go bigger than 22 here - not enough room!

Did my full license exam this evening and passed. That means I can have a slightly more legitimately poor excuse to buy lots of RF test gear and play with it. Ho Ho Ho 

But alas slacking is over as everything is unblocked so I shall return to computerland and slog out these problems for a few days at least. The eBay engine is still hammering away looking for bargains on my behalf though thus TEA is automated while my attention is diverted.. It found a couple of monster HP supplies this evening but they are too damn big and heavy to justify purchasing. I got the tape measure out and checked 

Going to bed! 

Congrats on getting your cert! We all knew you were certifiable, but now you have the paper to prove it! 

I can tell you this from personal experience... I used to feel the way you do about monitors; I spent some time working weekends at an e-cycle house recapping them when flat-screens were still worth the time to triage and repair them in large lots. The arrangement was straightforward; I got 1/3 of what I fixed. I could take units, I could take the cash they sold for, or I could trade value for value as long as it added up the same. They let me take all the lexan diffuser panels out of the defective screens I wanted, and they let me cherry pick the laptops and PCs at discount too. Was a good deal until we had a disagreement over what LCD projectors were worth; rather than let them eat my lunch trying to fix units that cost more for a good bulb to test with than they were worth, I moved on.

Coming back around to the point; I got pretty jaded about LCDs, I discovered they were all cheap sh** once you got the back off. I had new ones on my PC every week burning them in and using them before I sold them with a system. I just treated them like a disposable commodity.




MonoPrice Over/Under

Anyhoo... while I was doing this, we got several Compaq/LG widescreens in that were still under MFR warranty (big old 5-year warranty sticker on the back), and they traded them up to the next size larger. When the new ones arrived I was like "Holy hell... these are so much brighter and crisper." From then on, I only bought new for my own use; I'd stack the old one as a second monitor over my main monitor on one of these (for a while I had a 32" LG 2K monitor on there; that was sweet making PCBs with Eagle  ). Without fail, every time I would be astonished at how much crisper and clearer new looked side by side with old; and yes, this continued even into LED backlit models.

As a result, on something that's as cheap as a monitor nowadays, I'd much rather get the first 3-4 years of tip-top performance and save the eyestrain than put up with someone else's sloppy seconds.


mnem
That's muh story and ah'm stickin' teww itt.

[Specmaster]

Some good points there. The thing is I’ve got this tiny little box which is my comms supply. It weighs about 800g and quite happily pumps out 30A without even getting warm. Switchers FTW. The feed for the radio uses stranded wire about 4mm across. It’s like rope.  Looking at the HP supply, one thing that put me off is the refurb cost as well. The main filter cap in it is 34,000uF at 40V with an appropriately high ripple current. Equivalent part now is £53+VAT. Definitely quieter than the switcher but that has a cheat control (noise offset) which allows you to shift the switching harmonics out of the pass band. Plus a huge ferrite ring.

I actually gave my “scariac” away a few days back to a member of the local amateur radio club so he can repair his boat anchors. He has more space than me as his wife left him   . Has a workshop and parts stock that would put anyone to shame. Tried to get him to join here but the computer is the devil as far as he is concerned.

The female of the species is quite common in amateur radio circles. In fact the first radio amateur I ever met in the early 80s (I don’t classify my father’s CB escapades as official) was. She also showed me how to make my own fireworks 

Well you surely already knew how to make your own bangers that 34000 uF cap would make a monster one [emoji16]

From mobile device so predictive text might have struck again [emoji83]

[bd139]

@mnemneth: The newer panels are orders of magnitude better than anything that was being recycled a few years back. However these aren’t usually refurbed here. There’s a massive surplus of monitors due to stupid purchasing in IT teams. NHS are particularly bad at this. One trust had about 600 boxes new monitors go to a reseller because when you buy in volume you are buying per seat. So there are two tiers: discards and new out of box. Discards go straight in WEEE and are dismantled and recycled. It’s cheaper to recycle those than sell them off. They never see the market. The rest get shipped in pallets to resellers who discard any transit damaged units. What turns up is usually a new unit that has been sitting in stores for 3 years. They fire it up and sell as used because there’s no packaging. If I get two years out of a monitor I’m happy. For £1.58/month

Same with servers. The DL380g8 I just bought hasn’t even been fired up.

tl;dr: in EU, WEEE and IT purchasing killed off the tail end refurb market.

Anyway verdict out it’s arriving around 09:45-10:45

@specmaster: that cap would go with a big boom. It’s about 4 inches across

[bd139]

That worked! Perfect condition entirely as new. No dead pixels and it's so bright I had to crank it right down.



Excuse the windows 10 sin; it's currently connected to my windows desktop machine.

[Specmaster]

That worked! Perfect condition entirely as new. No dead pixels and it's so bright I had to crank it right down.



Excuse the windows 10 sin; it's currently connected to my windows desktop machine.

That's quite good, but I'll stick with my LG ones, no dead pixels even after 3 years of use and its set on 1920 x 1080 pixels so it offers a higher resolution with a contrast ratio of 50000:1, 3 year warranty, 2ms response time, ideal for fast moving games or watching videos on

[bd139]

Yep. This is 1000:1 and 5ms but I don't use it for games or video, just programming, CAD and desktop tasks. Plus can't see 1920x1080 ... Main thing though: £38! Bargain.

[med6753]

Excuse the windows 10 sin; it's currently connected to my windows desktop machine.

No sin in running WIN10. I'm quite happy with it. I think I have every tracker disabled but it's hard to tell because MS is a little sneaky in that aspect. And it gets along fine with the rest of my home network consisting of a media PC running WIN7 Ultimate and another laptop running dual boot WIN7 Home / Ubuntu 18.04 LTS.

[mnementh]

@mnemneth: The newer panels are orders of magnitude better than anything that was being recycled a few years back. However these aren’t usually refurbed here. There’s a massive surplus of monitors due to stupid purchasing in IT teams. NHS are particularly bad at this. One trust had about 600 boxes new monitors go to a reseller because when you buy in volume you are buying per seat. So there are two tiers: discards and new out of box. Discards go straight in WEEE and are dismantled and recycled. It’s cheaper to recycle those than sell them off. They never see the market. The rest get shipped in pallets to resellers who discard any transit damaged units. What turns up is usually a new unit that has been sitting in stores for 3 years. They fire it up and sell as used because there’s no packaging. If I get two years out of a monitor I’m happy. For £1.58/month

Same with servers. The DL380g8 I just bought hasn’t even been fired up.

tl;dr: in EU, WEEE and IT purchasing killed off the tail end refurb market.

Anyway verdict out it’s arriving around 09:45-10:45

@specmaster: that cap would go with a big boom. It’s about 4 inches across

Ahh, yeah... Those new IT overstocks are probably the ones I'm buying for $79 at Fry's and NewEgg.  I guess over here the lack of consumer protection allows them to be sold as new even though they've been bought and sold by an end-user already. I'm just paying a $10 "Finder's fee" for them putting the things all together in one place. And the full MFR warranty.

I'm totes down widdat.

Glad you like your new to you one; I think we're arriving at similar ends, but it's got a lot to do with what you can get used over here and the poor garbage:good ratio due to our lack of consumer protection.

Re BIG BOOM!!! etc... around here somewhere I have a couple 100,000uF/30V Seimens brutes from a 90's telephone ATM router backbone. They're 70mm x 150mm each.  I stacked them and used them as stiffening caps in several boom-box cars, then used them in the same capacity with a 20A Tripplite PSU for abuse-testing amps on the bench. 

Of course they're not as big as the 1F-30F stiffening caps you can buy online for car stereo nowadays; they start out around 80mm x 200mm weighing ~1.5kg. The really crazy part nowadays is the cost; you can buy a no-name 1F/20V cap for US$20 SHIPPED and cheap name brand 30F/24V Hybrid models for US$90 that have scary low ESR and are actually in the neighborhood of rated capacitance. Even cheaper if you're willing to scour fleaBay; you can often get name-brand a few years old for similar prices that are half-decent quality under all the plastic and bling LEDs.




I realize these aren't appropriate to most bench power supplies as-is because CC/CV; but put 'em in series and you can get 1/2F@40v for ~US$40 and 1F@40V for ~US$50. It doesn't MATTER if they're really only good for 60-70% of rated value at THOSE numbers, and I've been very surprised at how many of my modern SMPSes will happily charge them right up with no modification. CC/CV models will require some circuit adaptation; but it could be worth it.

I have a PSU I've been running made from two DPS-1200FB common-slot server power supplies (bought for ~ $15 each back before the "something-for-nothing" crowd started buying them up in hopes of scoring big in ButtCoin) in series for years; it powers my big LiPo charger. It's had a cheap 1F/24V stiffening cap across it all that time.

Excuse the windows 10 sin; it's currently connected to my windows desktop machine.

No sin in running WIN10. I'm quite happy with it. I think I have every tracker disabled but it's hard to tell because MS is a little sneaky in that aspect. And it gets along fine with the rest of my home network consisting of a media PC running WIN7 Ultimate and another laptop running dual boot WIN7 Home / Ubuntu 18.04 LTS.

meh.

I've had my fill of Ubuntu; its still as much "more time under the hood than using it" headache as Android.  Apple OS is off somewhere on its own little cloud of smug e-schmucks who spend the day sniffing their own farts; Winblows sucks and blows at the same time, but it's the evil I know so I still suffer with it. EVERY OS SUCKS.


mnem
*p00t!*

[nixiefreqq]

am noodling with my sdrplay rsp1a and the aussie anal spectrumizer software that was just released for it.

was pretty skeptical that a 1khz to 2 ghz SA could be acquired for 120 bucks...….but hey.....this little thing seems to work.

attached is a 20m sweep of my 5btv vertical antenna. 

test set up was an sg-677/u sweep generator modified to sweep 100x more slowly than usual, and an amtronix sw1200n return loss bridge feeding the sdrplay with peak hold enabled.

the aussie gentleman who wrote the SA software promises that the current 10Mhz sweep limit will be expanded to 500 Mhz in the near future.

ok....its not an hp8568a.   BUT it fits in your pocket and IT WAS 120 BUCKS w/free shipping from hro........AND the 35dB return loss it shows matches what my aim4170 indicates for that antenna.

could not be more pleased with this limey hardware/aussie software combination.  (now how come they got this to work.....but can't get their crappers to flush in the same direction?) 

[bitseeker]

Yeah, the narrow sweep is one of the main limitations of the SDR-based SA. However, as with most test equipment, it all depends on what your requirements are. Expanding the limit to 500 MHz sounds interesting.

[Specmaster]

am noodling with my sdrplay rsp1a and the aussie anal spectrumizer software that was just released for it.

was pretty skeptical that a 1khz to 2 ghz SA could be acquired for 120 bucks...….but hey.....this little thing seems to work.

attached is a 20m sweep of my 5btv vertical antenna. 

test set up was an sg-677/u sweep generator modified to sweep 100x more slowly than usual, and an amtronix sw1200n return loss bridge feeding the sdrplay with peak hold enabled.

the aussie gentleman who wrote the SA software promises that the current 10Mhz sweep limit will be expanded to 500 Mhz in the near future.

ok....its not an hp8568a.   BUT it fits in your pocket and IT WAS 120 BUCKS w/free shipping from hro........AND the 35dB return loss it shows matches what my aim4170 indicates for that antenna.

could not be more pleased with this limey hardware/aussie software combination.  (now how come they got this to work.....but can't get their crappers to flush in the same direction?)

The latter is just pure physics and if they ever did flush in the same direction then we're all doomed, as the world would have been nuked.

From mobile device so predictive text might have struck again [emoji83]

[Mr. Scram]

You guys are probably joking, but just to make sure as it's a common misconception.

https://www.snopes.com/fact-check/coriolis-effect/

[Specmaster]

I did wonder if anyone was going to take the bait 

[nixiefreqq]

You guys are probably joking, but just to make sure as it's a common misconception.

https://www.snopes.com/fact-check/coriolis-effect/

no way!  who you gonna' believe?  snopes or the simpsons?

[Specmaster]

I collect this beast today and after a day out in Cambridge with the family, finally got it home and powered the sucker up, here are some shots of displaying 234MHz sine wave from my Advance sig gen in digital mode, a shot of an analogue signal (far nicer), a quick glance inside reveals a conundrum, some IC's are dated 96 ut there are also a significant amount dated 98? There is no sign of any previous repair work being done so was this a scope made in 98 but with some left over 96 chips, or was it a 96 left in stock and then taken out and some options added in 98?

The main enclosure is plastic but the outer casing is metal, everything seems to be working just fine, now all I have to do is learn how to drive this and decide which of my other 3 scopes is going to make way for this one. I love the accuracy of the Advance sig gen as can be seen in the last 2 photos, the display reads 11Mhz and the sig gen also indicates on the pointer, 11MHz, bobbie dazzler.

It does run very hot though after an hour or so the top is very warm to the touch, unlike any of my other scopes, although the 1740A is nearly as warm when it runs but the Hitachi and the Iwatsu are just warm. The caps all look to be in fine condition visually, no signs of bulging, discharge, venting, discolouration etc and the insides are extremely clean as are the fan blades.

EDIT UPDATE It seems that it is indeed a 4th May 1998 model because thats what the screen displays when you ask for the model details etc from the menu, so I guess they over ordered IC's in 1996 and were still using the stock 2 years later?

[GerryBags]

That looks in great condition. In fact, it looks like another Specmaster Special, good find! 

[Specmaster]

That looks in great condition. In fact, it looks like another Specmaster Special, good find! 

Thanks, I've had my fair share of lemons so I suppose it the law of averages. Got my eyes on yet more items 

[Cerebus]

I love that PCB, so obsessively neat. If you had to fault find anything on that it would be a pleasure.

[Specmaster]

That's the only board that is fairly accessible though, the others need expansion cards which are going to be like pixie dust to find.