Test Equipment Anonymous (TEA) group therapy thread

[m k]

I understand that it's a standalone thing.
BBC Micro is needed for better representation of results.

[Vince]

I obviously don't have the user manual for this thing so we will never know.

However, given that it's got its own user interface with a display and tons of switches and buttons, and embarks its own CPU and EPROM containing 15 different programs... one can reasonably hope / assume that it was designed to be able to operate standalone, and require the BBC Micro computer only when strictly necessary, to retrieve data or run long and complex scripts that would be too tedious to enter on the crappy and cryptic keyboard of the instrument itself.

From what I understand, reading between the lines, the company designed it originally for / at the request of Leed's University, but it was also then offered to whatever school / Uni expressed an interest for it.

If the guy were asking 50 Euros tops for it, rather than silly 200 Euros, I would be willing to play with it a bit and figure it out on my own... sadly there is zero chance that he would take an offer that low, I know how French people are eh...   Still, you never know...it's such a specialty piece that it's possible nobody will ever be interested in it. Maybe he will keep it for sale for years and slowly lower the price.... So I will add the thing to my "watch" list, see how his ad evolves over the years... Just not holding my breath at all....

[Vince]

UPDATE : My bad, I just re-read the ad for this thing... it clearly states that it can be used standalone, phew...

[d-el]

I couldn't find a suitable section, so I posted it here.

In the video, I show how to measure the low current of my power supply.
A precision 1M resistor is connected as a load.

[Messtechniker]

Please correct:
M stands for MegOhm
and
m stands for MilliOhm

[Robert763]

Several O-rings arrived. The 25x2.5 mm ones were the best fit.
One of the housings was missing a countersink, which damaged the O-ring. I chamfered it.

<SNIP>

The original would have been imperial, 1" x 3/32" (25.4 x 2.38 mm). So the metric one is pretty close. Particuarly if the 25mm is ID. If it's OD them it might leak a bit. A standard aircraft part number would be MS28775-117 for 1" OD or MS28775-120 for 1" ID. Aircraft practice is to quote the ID and thickness.


Robert

[Robert763]

TEA, but not as we know it. It's not electronic.

It's a dial indicator so what    Well, the 0.001 increment mark on the dial isn't inches it's mm.
This little gem resolves less than 1 µm. It's a Compac, now TESA, model 556.  This level of resolution is in the relm of instruments like the Mahr Millimess. The Millimess has a resolution of 1 µm and a range of ± 50 µm. The TESA has a range of 5 mm. Current new price is over £400. I paid somewhat less

[d-el]

A standard aircraft part number would be MS28775-117 for 1" OD or MS28775-120 for 1" ID. Aircraft practice is to quote the ID and thickness.

The o-ring installed has an ID of 25 mm. It fits snugly in the housing. It fits tightly into the housing, so I had to unscrew the plug to bleed the air.

Tell me where I can find documentation for these resistors.

[McBryce]

Well, the 0.001 increment mark on the dial isn't inches it's mm.

That'll explain why they wrote mm next to it. 

McBryce.

[m k]

How many axle rounds before 1 um of tip is gone?

[Peter_O]

An old Keithley 2000 found a new home.
It's in good shape, will get some cleaning.
The display is even and bright enough. The picture was taken in full desk light.



S/N: 0688704
Display at startup says: Rev A07  02
Test runs without error.

First, it showed an overflow at startup without anything connected. 
Reset to factory default and saving that as user default fixed that. 

I got the unit sealed from a kind of recycler with the option to give it back.

What should I check before breaking the seal and discarding the return option(, which I will do later of course)? 
- self test - done: OK
- DC V, A, AC V, A, Ohm test measurements - done: OK
anything else?

Any advice, hint ...?

The option slot cover on the backside is missing. From pictures the cover seemed to be a sheet of aluminium. I plan to 3d print a cover and put an aluminium tape on the inside surface to make contact to the casing. But why do they use plastic screws to mount it?
Edit: The case holes are not tapped. Seems they just try to avoid sheet metal screws leaving metal chips inside the unit.

[d-el]

What should I check before breaking the seal and discarding the return option(, which I will do later of course)? 

Warm it up for a couple of days without stopping, measure the offset on the DCV.

I was looking for the K2000 as a universal multimeter, but I found the K2010, which is what I ended up buying. They look very similar.

[BILLPOD]

Good Morning Peter_O,  Nice find.  I got my Keithley 2000 about 4-5 years ago, off Ebay and paid $410, including shipping.  Mine also tested fine and had a seal on it, so I didn't open it.  I suppose I should open it now, to look for leaky caps. The memory in the meter told me it was only 4 years from the last calibration.  I was curious to the age of the meter, so I found a phone  number and called Keithley.  From the serial number they told me it was made in 1997.  I hope you enjoy yours as much as I have enjoyed mine.

[m k]

I might be in an on-going effort to downsize my TE collection, starting with the largest and heaviest pieces, but that doesn't mean I don't keep en eye out for the odd piece that might find my fancy, especially if it's small and light and affordable.

Are you still rejecting ebay?

Affordable there could be a thing for offloading.

[Vince]

Yes, no Ebay for me, as a seller at least. Every time I read about Ebay on here, it deters me.

Complex rules (I wouldn't even know where to start and really can't be bothered) need to setup an account, terms/rules that keep changing, for the worse, and of course the big no-no, buyers can make claims and ruin your life for no good reason and claim their money back, just because they can. Plus, people looking at ebay can be from all over the country, all over Europe, all over the world. They expect, take for granted that sellers will pack and ship. I certainly don't ! I am done with that shit. Not worth the trouble.

I prefer LBC, much simpler, local people, used to no shipping. Can't make claims or at least the platform won't / can't do squat so I am safe. You can bypass the platform's payment system to handle the transaction privately, cheaper (no fees...).
Every other year I might BUY a little something on Ebay, eventually, but sell ? No way on earth. Not worth the trouble.   

To each their own.

[TobyG]

Got another somewhat uncommon piece in, same as the last, made by Polar Instruments in the UK.

A Toneohm 950 Multilayer Shorts Locator.

I was looking for an 850A, which does basically all the same, functionally, sans the multilayer function, but I hardly ever need that, only one device I work on regularly even has a multilayer board and IIRC I only had two of them with a short between layers.
However, the seller of the only reasonably priced 850A (bare unit, no probes, but those can be DIY'd) I'd found was very slow to respond, I been waiting on that shipping quote for months, by now.
And in the meantime, this 950 popped up for under 100€ shipped...didn't have to think twice about that.

All probes included, save for the multilayer ones, but there's nothing fancy about them, easy to DIY,
already have everything required on order. Shoutout to @fcb and @Fraser https://www.eevblog.com/forum/testgear/toneohm-850a-short-finder-by-polar-instruments-a-look-under-the-hood/msg3489726/#msg3489726

Funnily enough, the original (optional, it does have an internal speaker) lightweight (as per the advertising) headphones came with the unit. I'd wager they are unused.
Regular probes on the left, current probe on the right.



My unit passed QC in 1998, to my surprise, no SMD components in sight.
And yeah, that shielding is simply a sheet of copper covered in tape, save for the area it's soldered.
Surprisingly much going on in there, compared to an 850A (https://www.eevblog.com/forum/testgear/toneohm-850a-short-finder-by-polar-instruments-a-look-under-the-hood/msg747013/#msg747013)






One odd thing I spotted, the solder mask had lifted in one spot, looked like what I'd usually see as a side effect of sorts of water ingress,
but that can't be it? Sorta odd. With too much heat from soldering I'd expect delamination, not the solder mask lifting.
Either way, cleaned it up, re-soldered and applied conformal coating (the UV solder mask I have at hand is rather viscous, so I opted for the coating to get it all under there).

Other than that, nothing wrong with the electronics, the case had one standoff broken off and two more with cracks in them, but that's what you get with old plastics.
Welded all that. Not pretty, but it should hold, for a while anyway.






Main PCB




All buttoned up again, working just fine.
Have yet to test the vectorized plane short finding, of course, for a lack of probes.
Should be getting that done some time next week.





Now it's awaiting its' first proper use. Not gonna see a ton of use, but I'll see if it saves me any time locating shorts.
Operator Manual, Service Manual and EPROM dump are up on elektrotanya, should anyone need any of that, btw.

[Peter_O]

And because it's christmas time I filled another gap in the collection.
A very clean HP3478A with a S/N from 1986 for a good price.
The upper right display corner is always on, but as it blends into the frame's shadow it does not catch the eye.



The self test runs OK and first measurements are in the ballpark.

[d-el]

Keithley 199 look like over the years. Warm, warm, recognizable design.

[Peter_O]

Keithley 199 look like over the years. Warm, warm, recognizable design.

The Keithley is definitely a long term keeper. The readability of the big LEDs is even better live. And eyes are'nt getting younger. 

[m k]

And LEDs are much more easily replaced than small VFD or LCD texts.

[Gertjan]

Yes, I also love my Keithley 199's 


IMG_2421__Keithley_199_ACV_dB_test-2000pix.jpg

I even wrote a TestController driver for it.

[TobyG]

The upper right display corner is always on, but as it blends into the frame's shadow it does not catch the eye.

Keep an eye on that. Take a closeup photo so you got something to compare to in the future, the spot will grow over time.
Same thing going on with my old JBC solder/desolder station. Both displays affected. Still readable for now, but who knows for how long...






In the meantime, materials to make the missing probes for the Toneohm 950 posted above already got delivered.
Couldn't help but put them together and give it a test run on a donor board I'd modified to simulate a short.

Pretty niche use case for me, finding shorts between layers, but this thing feels like cheating.
Connect it up, follow the arrows below the LCD with your probe, et voila.

[zepto]

I just got a thermometer with green LEDs.

I like the LED displays on Advantest r6871e and Fluke 8505a.

[Robert763]

A Toneohm 950 for <€100 is a bargain.Another Keithley 199  owner and fan here.
2000 series not so much so. Had a few at work on there second re-calibration (with no apparent fault) Keithley declared one BER  .  Being commercial there are no consumer rights etc. Put me right off them. It's not like there is anything special in there. Basically they will (would) not repair to PCB component level and the cost of fitting a new PCBwas more than 75% of a new meter.

Robert.

[wkb]

Same bloody problem I had with a Rigol SA: they did not want to do component repair, just swap the board at 80% of new cost or so. Of course this happened 1 month after the 2yr warranty expired.

I'll never touch that brand again