Test Equipment Anonymous (TEA) group therapy thread

[Specmaster]

I had been casually watching this rather rare Time Electronics 5075 DMM on eBay over the last few days and it had sat at £80 for the best part of that time but in the closing seconds of the auction it shot up and finally went for £361.77. Just wondering if it was anyone from this thread who was the winner in the end.

What attracted me to it was the firms reputation for top notch gear, British made and its lovely rich blue display, but hell it one hell of a boat anchor.

It also had a manual, which is useful since there's bugger all info on the web.

I was looking too, but the price was more than I am prepared to pay - at least until after I have sold some of my other 19" multimeters. Certainly at least one Solartron 7075 has to go, and if I get something like that 5075 then maybe a Datron 1061 disappears - but that would leave me with no Panaplex displays[1].

My Solartron 7081 is staying

[1] unless I repurpose the display from the third 7075

Yes, I thought it was worth watching (I knew of them and that would have cost a pretty penny or two when it was new. I used to visit from time to time (haha no pun intended) years ago in a previous occuption trying to sell them push buttons etc. Their factory is in Tonbridge, Kent and is/was quite small and you just would not associate expensive highend equipment coming out of such a humble building.

There was no way I was going to bid, it was already out of my league at £80 because it would mean I'd have to let most of my other good meters go just to fit it in on my bench.

[Specmaster]

That Time Electronics DMM is no boat anchor.
THIS is a boat anchor - and a strange beast to boot!

https://www.artisantg.com/TestMeasurement/83660-1/RCA_DAAH01_70_A_0039_Digital_Multimeter

Their both boat anchers, only difference is the size of the boat they are anchoring 

[Zucca]

Carbon fibre? I was going to recommend using one of the well known glass fibre cleaners/burnishers, but I have not heard of such one. Please tell us more!

glass fibre cleaner... sorry.

[tggzzz]

There was no way I was going to bid, it was already out of my league at £80 because it would mean I'd have to let most of my other good meters go just to fit it in on my bench.

If you say things like that, you'll be persona non grata here. Hell's teeth, you've got a floor haven't you (That's where my 7075s and 1061 are).

Oh, and there's my Fluke 8125a on the ground in a very damp shed - but that's hermetically sealed military field DMM, so it will be OK

Memo to self: work up the courage to open up and fix my dead Datron 4903 calibrator. No schematic, up to 1kV output - on unshielded banana sockets: what could possibly go wrong? The two other calibrator boxes contain ~200 Vishay oil-filled foil resistors; the modern equivalents cost  ~£30 each

Fluke 8125a:

[Specmaster]

There was no way I was going to bid, it was already out of my league at £80 because it would mean I'd have to let most of my other good meters go just to fit it in on my bench.

If you say things like that, you'll be persona non grata here. Hell's teeth, you've got a floor haven't you (That's where my 7075s and 1061 are).

Oh, and there's my Fluke 8125a on the ground in a very damp shed - but that's hermetically sealed military field DMM, so it will be OK

Memo to self: work up the courage to open up and fix my dead Datron 4903 calibrator. No schematic, up to 1kV output - on unshielded banana sockets: what could possibly go wrong? The two other calibrator boxes contain ~200 Vishay oil-filled foil resistors; the modern equivalents cost  ~£30 each

Fluke 8125a:

Floor, what use is a bench meter on the floor?? Hell no, under my bench there is just enough space for my feet when sitting at it, shareing the space is 1 full size computer tower and I mid sized tower computer and a large Dell sub woofer as per photo posted a few days ago and 2 laptops stored on their side. In fact a lot bathrooms are bigger than the bedroom that houses my lab. My bench is an old office desk. When I see photos of some you guys labs, I get all jelly., so that 5075 would have to sit on my bench or not at all 

[0culus]

Incidentally all audiophilery is absolutely bullshit through and through. Even spending £10k on something which is pretty low balling in the audiophile stakes means you’ve spent £10k on something to listen to a low rate recorded by some cheap ass muso hammering shit out on a set of instruments held together with duct tape while the sound engineer was stoned and drunk at the same time. Buying a £50 cable doesn’t get rid of that rusty POS Chinese 1/4” patch they used when they recorded it.

Yes but it takes a whole lot of expensive gear to reproduce the sound of that crap faithfully. 

To be fair, I would like to hear it in person and not on youtube. Of course, spending that much is insane, but youtube compression definitely isn't going sound like being in the room. also I would like to hear some 24 bit Telarc recordings on that. They sound damn good even on a "plebeian" hifi system that's in my price range. 

[0culus]

There was no way I was going to bid, it was already out of my league at £80 because it would mean I'd have to let most of my other good meters go just to fit it in on my bench.

If you say things like that, you'll be persona non grata here. Hell's teeth, you've got a floor haven't you (That's where my 7075s and 1061 are).

Oh, and there's my Fluke 8125a on the ground in a very damp shed - but that's hermetically sealed military field DMM, so it will be OK

Memo to self: work up the courage to open up and fix my dead Datron 4903 calibrator. No schematic, up to 1kV output - on unshielded banana sockets: what could possibly go wrong? The two other calibrator boxes contain ~200 Vishay oil-filled foil resistors; the modern equivalents cost  ~£30 each

Fluke 8125a:

Fairly sure that would survive a nuclear holocaust. 

[Cerebus]

... and then consider an orchestra recorded with the hypothetical perfect recording chain.

Where do you put the microphones? By the conductor, in the first/tenth row, central/left/right, etc. In all those places you would perfectly reproduce different sounds. Which of those would be "righter" that all the others.

The general approach taken by all the classical recording engineers that I have known is to use some kind of co-incident pair out front (although some use spread pairs, or M/S pairs, or even more exotic two/three mike setups) in roughly something like an 'audience' position. The purists stop there. The non-purists add a few spot mikes for the weaker instruments or instruments that have significant solos in the piece, and then spend ages sorting out the delay/phase issues that this introduces.

When I speak of is 'back in the day', when I used to do some recording engineering -  close miked popular music recorded in a studio. In those days the classical boys tended to work in classical performance venues and recorded straight to ¹/₄" stereo tape at 30 inches per second. Hence they had to get the mix right then and there, and fix problems before they made it to tape. Nobody was going to lug a heavy 24 track 2" tape machine out to a classical venue and deal with all the attendant hassles. Nowadays multi-track is a damn sight more portable and I'd imagine that the classical boys do multi-track and can fix more (but not all) spot mic placement issues in 'post'.

If you ever listen to a older classical recording and a naturally loud instrument like a trumpet sounds like it was recorded through a comb filter it's those phase/delay problems rearing their head as the instrument gets picked up by the main mike pair and one of the spot mikes simultaneously but over different length paths.

[Cerebus]

Their factory is in Tonbridge, Kent and is/was quite small and you just would not associate expensive highend equipment coming out of such a humble building.

Back in the 80s they used to have offices next to Langley station (near Heathrow). Used to pass by on my way to my then girlfriend's place in Langley.

[tggzzz]

Floor, what use is a bench meter on the floor??

No use whatsoever. When you need it you take stuff off the bench and put the meter on it. Stack them up three high if you are comparing them over a period.

Hell no, under my bench there is just enough space for my feet when sitting at it, shareing the space is 1 full size computer tower and I mid sized tower computer and a large Dell sub woofer as per photo posted a few days ago and 2 laptops stored on their side. In fact a lot bathrooms are bigger than the bedroom that houses my lab. My bench is an old office desk. When I see photos of some you guys labs, I get all jelly., so that 5075 would have to sit on my bench or not at all 

Pah. If all your kit fits on a bench then you don't belong here

I have an old kitchen table as a bench, as shown below. You can see that it isn't exactly large; the scope is a Tek 485, the soldering stuff, PSUs and computer live on the shelf above, and a spec an is visible on the floor.

Now there is an unusual amount of crap on the bench at the moment; the 19" rack is the Datron calibrator. The top third is the 1kV amplifier, with the outputs shown. The wires are PTFE

[tggzzz]

There was no way I was going to bid, it was already out of my league at £80 because it would mean I'd have to let most of my other good meters go just to fit it in on my bench.

If you say things like that, you'll be persona non grata here. Hell's teeth, you've got a floor haven't you (That's where my 7075s and 1061 are).

Oh, and there's my Fluke 8125a on the ground in a very damp shed - but that's hermetically sealed military field DMM, so it will be OK

Memo to self: work up the courage to open up and fix my dead Datron 4903 calibrator. No schematic, up to 1kV output - on unshielded banana sockets: what could possibly go wrong? The two other calibrator boxes contain ~200 Vishay oil-filled foil resistors; the modern equivalents cost  ~£30 each

Fluke 8125a:

Fairly sure that would survive a nuclear holocaust. 

Or, in the shorter term, squaddies and cars. The inside of the case shows, if you look carefully and know what you are looking for, a 1" gap between the inner frame (and electronics) and the green outer case. Under the perforated metal grille there are paper bags of dessicant, and there is a humidity indicator visible.



Other images here: https://www.eevblog.com/forum/testgear/fluke-8125a-military-dmm-teardown/msg2540730/#msg2540730

[tggzzz]

... and then consider an orchestra recorded with the hypothetical perfect recording chain.

Where do you put the microphones? By the conductor, in the first/tenth row, central/left/right, etc. In all those places you would perfectly reproduce different sounds. Which of those would be "righter" that all the others.

The general approach taken by all the classical recording engineers that I have known is to use some kind of co-incident pair out front (although some use spread pairs, or M/S pairs, or even more exotic two/three mike setups) in roughly something like an 'audience' position. The purists stop there. The non-purists add a few spot mikes for the weaker instruments or instruments that have significant solos in the piece, and then spend ages sorting out the delay/phase issues that this introduces.

When I speak of is 'back in the day', when I used to do some recording engineering -  close miked popular music recorded in a studio. In those days the classical boys tended to work in classical performance venues and recorded straight to ¹/₄" stereo tape at 30 inches per second. Hence they had to get the mix right then and there, and fix problems before they made it to tape. Nobody was going to lug a heavy 24 track 2" tape machine out to a classical venue and deal with all the attendant hassles. Nowadays multi-track is a damn sight more portable and I'd imagine that the classical boys do multi-track and can fix more (but not all) spot mic placement issues in 'post'.

If you ever listen to a older classical recording and a naturally loud instrument like a trumpet sounds like it was recorded through a comb filter it's those phase/delay problems rearing their head as the instrument gets picked up by the main mike pair and one of the spot mikes simultaneously but over different length paths.

All of which indicates there is no single "true" sound. It is all a sound engineer's concoction

[mnementh]

3D printed bombs. Now there’s an idea 

Whoops, bd139 just found himself on another watchlist.

He's already boned; receiving care packages from ME. 

With rotten shellac on still-good copper like that (all those "dark" areas of Shellac over copper are "rotten"), leaving it will just result in the rot spreading; but you have to balance the need to repair against the possibility of damaging a trace. Correct solution is to mask off the edges of the trace with something like Kapton tape to protect the substrate, use fine steel wool to scrub all rotten shellac off a section of trace leaving shiny copper, then remove the masking and move to the next area of trace until it is all either clear shellac or shiny copper.

After that, clean with IPA and paint with new shellac or clear fingernail polish. Epoxy is also perfectly fine, I've used it in a pinch; just be sure to make a thin coating using a flattened & cut-off Q-Tip stick or coffee stirrer as a squeegee.

(SNIP)

mnem
moo...?

Thanks mnem, crazy idea don't spit me in the face, would a sharpie ink be sufficient to protect the substrate? It would be so much quicker and precise.

Not gonna spit; that's a good question which shows you're thinking.

I've used Sharpie to "re-blacken" black-oxide Philips screws that have been boogered-up and have proud, shiny metal; they look much better at first but will rust after a few months. Based on this, I've never tried it as a substitute in this application, though I HAVE recolored over traces with green Sharpie after sealing with clear nail polish.

Clear nail polish is something every nerd should have in his cupboard anyhow; from sealing tuning cords to keep them from fraying to use as easily-broken-loose nut-locker for uber-small diameter screws to fixing scuffed magnet wire... it's quick-drying and good sealing properties make it a near-universal un-solvent.

I'm stuck in a similar conundrum with one of these:       A Heath-Zenith Z-120 (only with working 5MB Winchester drive)...
mnem
*mocked*

A 5GB Winchester drive!!!  That must be worth a fortune! 

McBryce.

It most certainly WOULD be. Literally one-of-a-kind; from some alternate reality. I've gone back & corrected my typo; thanks for the heads-up. And the good-natured mocking, which I certainly earned. 

mnem
*slogging through the backlog*

[beanflying]

Most of the FDM printers can get to similar resolution. Standard is 0.4mm nozzles and 0.2mm layers. 0.1mm Layer is fairly easy to go and dropping the nozzle size to 0.3 works and you can get 0.2 (tough to get it working well)

Here are some examples of the same components made in three different materials

• white: DirtyPCBs' SLA
• purple: Shapeways' strong and flexible nylon
• red: Prusa printer's PLA, 0.4mm nozzle, 0.15mm step, 100% infill

In the pictures below, the surface finish of the PLA and nylon is easy to see, but that of the SLA is so smooth the part appears to be out of focus!

The first component is a scope probe tip designed to (successfully) minimise the inductance of a ground lead. The dimensions and finish are non-critical, and the internal nibs are an interference fit over the probe.

The nylon is the best material since the outer walls deform when the probe is inserted, gripping well but allowing the probe tip to be easily removed without damage to the probe. The PLA works, but requires careful reaming out for it to be an interference fit, and its hardness an roughness damages the probe. The SLA is intermediate. Overall the PLA is sufficient to prove the concept, but it unsatisfactory otherwise.


The second component is a handle for a Tek P6013 HT probe. The key design feature is that the 2mm pitch thread which screws into the HT part of the probe.

The SLA variant works perfectly, inparticular the thread works surprisingly well. The PLA variant is a failure: the thread doesn't screw in, and the slicer automatically modified the shoulder's overhang.


The final component is a collet for a Tek 24x5 squirrel cage cooling fan. The design points are the compression of the collet inside the fan, by being pulled to the left with a screw.

Lightly compressing the PLA variant with fingertips caused it to fracture along a layer boundary, so it is unlikely it could survive the tension exerted by the screw. That's not entirely surprising, PLA (and similar materials/depositions) was never going to be a good material for this task. The SLA variant works well, and will probably be OK in the medium term: the SLA scope probe handle is fine after 4 years, and the collet won't get very warm.

You can not make any conclusions with a printer that is clearly not set up correctly let alone based on a sample size of one. The collet example with the PLA shows retraction issues (random wisps and blobs in between the collet jaws), over extraction (bulging on the sides or possibly belt issues) and I suspect the temperature of the extruder is 5-10 degrees to low (shot is a little fuzzy but the bright shiny lines show clean separation on most of the fin so poorly bonded on the sheared layer). As to the option to use FDM the jaws are to small in size with that layer orientation let alone with a badly setup printer.

As to threads anything M12 course and above works fine in PLA, M10 Course with a tweak to the thread clearances works too but nothing under that. An example below close up of my Fluke 5616 RTD case which is an M14 picked because it was close at hand.

There is no argument about the surface quality of SLA over FDM. Putting up one off 'fdm inappropriate' designs/models and poorly setup printer to back your ongoing position with very limited use cases in particular hands on use remains an issue.

[mnementh]

I see that, in my temporary absence, Med has gone from a quite understandable obsession with Tek blue to a worrying one with Smurfette blue. One shudders to think where this may end up. It's the sort of think that can lead to dressing up in furry costumes and meeting with like minded people in smoky dive bars or seedy hotel rooms. Marginally acceptable as a detour in the young when they're at that "finding themselves" stage, but distinctly unnatural in men of our age unless they are judges, politicians or any of the occupations where the holder went to a certain class of school, one of a particular set of universities and had a nanny.

How did I manage to become so (in)famous??? 

Natural. Fucking. Talent.

mnem
One might say med is GIFTed...

[mnementh]

   mnementh what about now? Thanks for making me work like a dog during the week-end. Sorry the out of focus.... PS: glass fiber cleaner is like magic...

Oh, a glass-fiber solder-pad-cleaning pencil is fucking magic for this work; but I still prefer to mask the adjacent substrate, and cleaning off old shellac tends to foul up a tool which is a) not in most people's kit and 2) refills can be pretty pricey unless you get them by the boatload China-direct.

Assuming those yellowish areas are flux, not discolored shellac, then yes... looking good. Ready to clean off flux and paint with nail polish. 

mnem

[Specmaster]

Floor, what use is a bench meter on the floor??

No use whatsoever. When you need it you take stuff off the bench and put the meter on it. Stack them up three high if you are comparing them over a period.

Hell no, under my bench there is just enough space for my feet when sitting at it, shareing the space is 1 full size computer tower and I mid sized tower computer and a large Dell sub woofer as per photo posted a few days ago and 2 laptops stored on their side. In fact a lot bathrooms are bigger than the bedroom that houses my lab. My bench is an old office desk. When I see photos of some you guys labs, I get all jelly., so that 5075 would have to sit on my bench or not at all 

Pah. If all your kit fits on a bench then you don't belong here

I have an old kitchen table as a bench, as shown below. You can see that it isn't exactly large; the scope is a Tek 485, the soldering stuff, PSUs and computer live on the shelf above, and a spec an is visible on the floor.

Now there is an unusual amount of crap on the bench at the moment; the 19" rack is the Datron calibrator. The top third is the 1kV amplifier, with the outputs shown. The wires are PTFE

Pah to you as well  , my bench . desk is approx. twice the area of you table, sitting on the bench, beneath what was a full width monitor shelf, I have 2 x 30V 5A PSU's 1 x desoldering gun, 3 x NAS drive units and TDS210 scope, on the monitor shelf I have 1 signal gen TE-20D, 1 x TTi TF930 3GHz counter, 1 x TTi TGP110 10MHz pulse Generator, 1 x HP 3478A, 1 x HP 3466A, 1 x HP3468A, 1 x TTI TG120 20MHz function Generator, 1 x TTi x 1905A, 1 x Fluke 8840A, 1 x Fluke 8842A 1 x Solartron 7150plus DMM and 24" Monitor. Screwd beneath a wall shelf above the monitor shelf, I have 1 x XJW01 LCR meter, 1 x 25MHz DDS signal Generator, 1 x Heathkit IG-4505 calibrator, above that shelf I have numerous smaller items, battery power scope, AD584-M, other LCR meters and USB microscopes resistance substutition boxes, on top of the mid sized tower I have another Solartron 7150 plus DMM. On computer desk to my left I have Fluke PM3390B combiscope, 2 x T12 soldering stations, stacks of handheld DMM's, active scope probe, tong testers and intelligent tweezers etc and loads of old analogue meters and MS7221 DMM calibrator and I have other shelves full of other handheld DMM's etc and on the floor I have an advance signal generator, a HP A1 plotter and a Brother A3 printer and scanner with isolation power transformer and various other bits of gear in the triage queue and a HP colour laser printer, jees what have I got to do before I belong here then

[mnementh]

   Wow, is this a audiofool or an audiophil, thoughts please, but this is alledged to be a 1,000,000$ audio system and to me, it sounds nothing special at all. And the unique thing about it is that does not use any capacitors at all in its design.

      

Hmmm... Sounds great watched over my $10 saved-from-the-garbage-dump Logitech 3.1 speaker system powered by a whole $2 worth of PAM8403 Class-D amplifier brick sandwich with custom-built heat-sink... that does in fact have several MMLCCs, but not one electrolytic anywhere. 

mnem

[0culus]

I'm also going to put this out there: I don't care how much those speakers in the $1M system cost...they are BUTT UGLY. 

[worsthorse]

Please forgive me for wandering off on a tangent during this fascinating discussion on audiostoopid but I actually spent a couple of hours at my bench today working on test equipment.   

I replaced the Tek power plug on the 184, which is a right pain in the ass, with a power cord, and no longer have to look at this:



Letting it warm up for two hours    as suggested in the service manual, I was pleased to find that the local oven-ized 10MHz oscillator running at a steady 10,000,032 Hz and drifting no more than +/- 1Hz. While that is well within spec, we will see if we can do better a little later. And to be honest, the oscillator was running at that frequency within ten minutes of turning it on and didn't move after that.

First thing I found was roughly 200mV of 10MHz ripple on the DC rails (12, -30, 125). This is a good bit higher than it should be, if I am reading the specs correctly.

Then I worked my way through different combinations of markers. At 1us and longer, it puts out a good signal:



But at 500ns, things start to look not so good:



Same for mixed markers (500ns and 100ns):



The top trace is the marker output channel, the bottom the trigger output channel.

It is not surprising that there's cross talk here, nothing in the box is shielded:






There's also a little 500MHz filter board on the side and in the open that I didn't photograph. I have to check the manual, but I would guess that the crosstalk is small enough that it would meet spec. But even if it is, the marker output below 500ns isn't right and needs to be addressed.

I will start by looking at the power supply more carefully tomorrow and see if I can clean it up. It has been a while since I worked on anything generating frequencies like this...

[beanflying]

I think those daring to keep on topic should be flogged with a wet lettuce leaf. Maybe Icebergs to the head for the rest of us 



Back to playing with my Laser and Wood......

[med6753]

Please forgive me for wandering off on a tangent during this fascinating discussion on audiostoopid but I actually spent a couple of hours at my bench today working on test equipment.   

I replaced the Tek power plug on the 184, which is a right pain in the ass, with a power cord, and no longer have to look at this:

.......snip.....


Tggzzz has one of these beasts too and should be able compare his with yours to determine if in fact you have an issue.

[tautech]

I occasionally keep an eye out for Tek P6021 current probes and just nabbed one on the 'Bay that had started at just $69. 
Got it for just over $235 with a few seconds to spare. 

That's my TEA budget gone for a bit as I don't need anything else....that I know of ! 

OK so I bought this fair and square with a single last minute bid with a max bid of a good bit more.
Paid for it a few days ago using the 'Bay option of additional delivery costs to a kind member that's prepared to on-ship it to me in NZ as the seller listed it was only for US delivery.

Now I get 'Bay mail the seller has cancelled the sale and a refund is coming !    

It's a sale contract is it not ? 
What's up with the world when you buy something fair and square only to have the buyer back out of the deal without so much as a message explaining why ?

My 100% buyers rating is at risk ! 
So wise 'Bay members, what can I do now ? 

[Black Phoenix]

OK so I bought this fair and square with a single last minute bid with a max bid of a good bit more.
Paid for it a few days ago using the 'Bay option of additional delivery costs to a kind member that's prepared to on-ship it to me in NZ as the seller listed it was only for US delivery.

Now I get 'Bay mail the seller has cancelled the sale and a refund is coming !    

It's a sale contract is it not ? 
What's up with the world when you buy something fair and square only to have the buyer back out of the deal without so much as a message explaining why ?

My 100% buyers rating is at risk ! 
So wise 'Bay members, what can I do now ? 

Don't worry, you are not going to get a bad feedback, to be sure I thing that even the seller will not say anything regarding this. Sometimes that happens, you win something and then the seller changes ideas and refund you with the excuse that the item is broken or was lost or whatever. Do it too much times and you have to provide explanations to eBay and will not be able to sell for a while.

Same as you buying something and then asking for a refund because you changed ideas. It sucks but to me happened sometimes. Probably he wanted more for the item and since it didn't achieve what he wanted, now he will re-list it in a later date. Regarding what you can do, well that is not a dispute and even if you open a dispute it will be closed as soon the seller refunds you. That's how eBay is. Even if you say you want the item in the conditions he show in the ad, not the refund, you are powerless.

[mnementh]

Yup; sad but true. He IS allowed under the rules of eBay to cancel the sale, even for "seller's remorse". The only thing you can hope for is that he makes a habit of acting on it and gets booted... but then you're condemning dozens of other eBayers to the same fate.

mnem
*toddling off to ded*