Test Equipment Anonymous (TEA) group therapy thread

[Specmaster]

See below 

That is a massive fail. I would expect a linear supply if it was going to fail to suddenly output nothing.....not jump up to 56V. Can you imagine what would happen if you had a 3.3V logic board connected when that happen? That would be spectacular flames that would make bd139 proud. 

Have you noticed how many Mastech power supplies I  have owned? I've fixed a lot but owned precisely ONE and that was a very long time ago

All the cheap ones are nasty as fuck. There's usually a cost cutting thing in them which goes bang pretty quickly. I was going to write a detailed rant about this but decided that a visual explanation is better:



I have fixed at least 5 that have done this over the years. And 3 with other problems, usually someone shorted the output diode by connecting a battery the wrong way across it 

Edit: for some absolutely stupid reason the failed position of the relay is always full voltage. I don't know why they do that. The whole design works rather well apart from that gigantic cock up. I suspect these are "cut and paste" designs mostly. I've seen several variants with exactly the same schematic.

Mine is nothing like that at all, it has 4 transformer taps, 2nd tap comes in around 6.5V, 3rd tap 15.5V and 4th tap at 24V. I have used it quite a bit and it has so far given me sterling service. The last time I saw the particular model I have it was listed around the £100 mark but at that kind of money I'd rather get a 2nd hand TTi unit or similar.

[bd139]

Yeah that’s the extension. Same failure mode. Just more relays!

Definitely agree with TTi ones. They will run the peak rated power into a short with convection only heating 24/7/365.

[Mr. Scram]

The Korads are fine too. Dave's first one blew but they've been known to be pretty good since that got fixed.

[med6753]

I also went to my local Lidl store today and in their Middle of Lidl special buys area I spotted this rather handy tool holder with illuminated magnifying glass with 2.5 & 5x optics and it also comes with vertical iron holder which will accept almost any iron I think, for only £5.99, loving mine, ideal for a small bench top because of the small footprint.   

That is a neat tool. Want one. But Google search seems to indicate that it is only available in the UK. Shucks! 

[Martin.M]

http://www.wellenkino.de/e108/mechanik.mp4

 

[PA0PBZ]

http://www.wellenkino.de/e108/mechanik.mp4

It's beautiful and sad at the same time. SDR is replacing all this mechanical stuff but now at least you can create something at you workbench which would not have been possible without it. Once a Racal R17 was my most sophisticated receiver, but times have changed. I still like the oldies but I simply don't have the space for it.

[med6753]

http://www.wellenkino.de/e108/mechanik.mp4

 

German engineering at it's finest. 

[Martin.M]

oh the NL is reading here also 

This radios are a set of two:

the Telefunken E108Lw4 is the VLF/LF Radio (10kHz up to 1.8MHz, AM+BFO) and
the Telefunken E104Kw4/7 is the SW Radio, up to 30MHz (AM,FM + BFO)

my E104 I have picked up in Hertogenbosch (den bosch, nl)

[mnementh]

Birthday party for the boi at Dave & Buster’s; mother & I decided he was old enough to try “Chuck E Cheese’s for grownups”. 

We’ll see if his head explodes when he opens his cheap android smartwatch...

mnem
 

[Neomys Sapiens]

1.) The Philips LCR-meter is here, but still unpacked.

2.) My pictures should get better by the help of a Lumix DMC-LX100.

3.) Congratulate if you want, I'll celebrate anyway: My first two devices are certified under the RED.
(Now come the hard ones, but not today.)

1. You mean un-unpacked, don't you?

3: Congratulations! But what is 'the RED'? Did I miss something?

2. Now that you have a decent camera, flood us with great pictures! 

1.) Yes

2.) The Radio Electronics Directive, which has superseded the R&TTE and brought some nasty changes.
Aeronautical (civil) exemptions have run out and receivers get the same loving care as transmitters. And you are still not allowed to self-certify when no harmonized standard exists. So we had to feed the 'Notified Bodies', and extensively so. In direct comparison, I am willing to attest a benevolent and charitable nature to all four organized crime structures of Italy.

And a harmonized standard for secondary radar/ADS-B etc. is not in sight, as the commitee whose obligation it is to produce one is a gathering of hyenas, crocs and wolverines.

And they are a reservation for the most unimaginative, stupid and stubborn people in the technical sector. While I would never doubt the merits of the VDE/DIN regarding safety, interoperability and more, those rules need interpretation with knowledge.
One example: My AC power input connector is a special derivative of MIL-C-5015 WITH a leading PE contact that is connected within the connector to the shell. Both in the Plug and the Receptacle. But for a full year I had to fight with a Non-pass of EN/IEC60950 because they only saw the soldered ADDITIONAL PE connection on the inside of the receptacle, because the moron in charge did not see a VDE sign on the connectors. But the varistors, which are subject to a much feared failure mode where they become incendiary elements, did not show up in that report. Well, I have them thermally fused anyway. Also, during our torments they changed EMC standards twice, for another round of bloodletting.

Then they make up very funny rules to additionally do you in. For example, if at years end you have not shown that you can complete the assessment within 1 month, they expect you to apply anew and they throw your data away. I am still trying to convince my superiors to denounce them at the oversight authority for the 'Notified Bodies'.

[tautech]

Made up a simple test board for the NanoVNA, like others seen on the internets. You can test caps, inductors, and resistors or make a Pi or T arrangement. Shown are the readings from a 100 pF cap and 680 ohm resistor.

For accurate characterization of stuff you really need to exclude cabling.
I split a lot of these with hendorog just for that sort of testing.


https://www.aliexpress.com/item/33019328733.html?spm=a2g0s.9042311.0.0.e8204c4ds2kIP8

[Neomys Sapiens]

OK, got it. Now that explains why I have a deer in the headlights look on my face. 

This will make sense to you and I more or other non RF nerds 

Hey! Where did you obtain that snail? It's classified and the people at [classified] worked hard at it's training!

[xrunner]

For accurate characterization of stuff you really need to exclude cabling.
I split a lot of these with hendorog just for that sort of testing.


https://www.aliexpress.com/item/33019328733.html?spm=a2g0s.9042311.0.0.e8204c4ds2kIP8

Yes indeed that would be better (the cable was in the calibration but indeed it contributes to some error). I may build another one with that on one end but for now it's just a little experimental thing. I could also just put a male-male adapter on the end instead of the cable.

[tautech]

There might be a PCB mount female available, I dunno.
We got a heap of those male ones too for doing various PCB projects like your component tester.

hendorog has a heap of RF stuff he's built for his VNA's.

[beanflying]

Tiny TEA item 6 channel PIC based datalogger came from Malaysia via one of it's Northern provinces Germany to Oz eBay auction: #391932720671 Surely DHL does enough traffic to have an Asian hub  Software is simple and functional -thread to follow when I clear away the Plywood.

Also a Decade Ratio Transformer in a Box at the local Post Office but that can be tomorrows toy as I am to lazy to walk the 200m to get it due to low caffeine and high CBF to put shoes on ....

[mnementh]

I have a supposedly “good used grade B” lcd/screen for my iPad Air II waiting at my Dad’s in New York; offered for $35 delivered I had to take a chance on it as the new aftermarket one I put on in January has turned out to be pretty much globally a POS. First the home button didn’t work, either with the original or the new one that came with, and now there’s a region of the screen that has very poor sensitivity and is virtually impossible to type on.  All discovered long after any reasonable warranty period.

Not worth spending any more than that on it as I can get into a similar new one for $279. 

mnem
Meanwhile, we’ve spent over a grand in hotel rooms since we left Houston...

[Carl_Smith]

I have fixed at least 5 that have done this over the years. And 3 with other problems, usually someone shorted the output diode by connecting a battery the wrong way across it 

I've never done that.  Nope.  Never connected a 14.4V power tool battery that can put out many tens of amps wrong way around to my bench supply and blown the output diode.  Then I didn't sit there wondering why the supply was stuck in constant current mode even with nothing connected.  I mean, I have a degree in electrical and electronics engineering.  I know better than do things like that.

OK, I've done exactly that. 

[beanflying]

Recovered thanks to the power of Coffee and a yapping muttley that needed a walk before it drove me nuts.

5 minute test and teardown of the newly arrived Gertsch RT-11H Decade Ratio Transformer. Arrived very well packed for it's $17USD frieght bill  eBay auction: #264459255508 Seller has some other interesting items of TEA (mainly HP) and prosthetic legs for sale 

Hooked it up to the AC Calibrator and 121GW instead of dropping one of the bench DMM's over but looks like it is a winner and still very accurate. Full play later with some more care and better meters. Inside not much to see and the main trickery is buried under potting compound. Switch clean and lube is about all there is to play with.

Eventual use - Occasional like my straight resistance Ratio divider 

[worsthorse]

Here's a partial pile of the equipment I've repaired (or calibrated or repaired and calibrated) since the beginning of September:



I was hoping to include a stack of RTTY equipment. Alas, it still waits in the queue because I am slower at getting stuff done that I imagine and some of this stuff was much more broke than I thought.

All of the stuff in the photo is going to Rickreall where, hopefully, it will find new homes, each and every one.  One piece of TE, the 0542 calibration fixture, is going to someone in France.  There's also a couple of crates of repeater boards, connectors, and such. It would be wonderful to come home with none of it.

That said, I am experiencing pre-seller's remorse, which may mean that I keep the 191, 114, and 106 sig gens, because well, I get apparently develop attachments to the stuff I manage to bring back to life. 

[worsthorse]

And today's bench project, the Tektronix Television Test Signal Generator:



Tomorrow, I will put up a separate thread on this one but here's one photo of the inside:



A whole lot of small scale TTL logic on that board!  Sorry for the sideways photo.    Will fix that tomorrow, too.

[bd139]

That’s pretty cool. Is that before TTL? Looks older!

[beanflying]

Things to do with the inner scrap bits of Laser Cutting Extractors. New Bench Coaster, single application of Beeswax and Oil so far

[tautech]

Bean, have you used Tung oil on wood ?

[beanflying]

A long time ago. Haven't seen it around in particular either in the local hardware stores. Will add another few coats to the coaster before I decide on a finish for the other bits under construction in the Jarrah.

[tggzzz]

A whole lot of small scale TTL logic on that board!  Sorry for the sideways photo.    Will fix that tomorrow, too.

Not TTL - RTL. There are a lot of Fairchild uL923 JK flip flops on that board. They run at up to "2m/c" on 3.6V.

The microLogic family was the first available set of integrated circuits.

Count yourself lucky they didn't use the analogue /2 and /5 circuits in the Tek 184