Test Equipment Anonymous (TEA) group therapy thread

[Cerebus]

I wouldn’t rely on bubble wrap for that sort of thing. Needs some polystyrene with cut outs for sticky outy bits then bubble wrap around that. Need to support the main mass of the unit and make sure that any impacts are absorbed by that rather than smaller parts.

I agree but, in ideal circumstances, I'd substitute polyethylene foam for polystyrene foam. At low levels of clobbering the two are equally effective, during really rough handling the polythene behaves better transmitting less shock than the polystyrene, at extreme levels (think sledgehammers on the corners) polystyrene comes back as best again because it will absorb energy by permanent deformation.

[med6753]

could not resist  a PF Ummagumma CD,

There goes my lunch money for November ...

Definitely. 

[Specmaster]

It looks to be a little light on bubble wrap TBH, there is too much movement in the box for my liking. I always pack anything like with about 50mm or more thickness of protection all round, especially where there are controls or sockets.

Some of the bubble wrap was already taken out but in general I agree. Always a bit of a tradeof between a well fitting box and a large box where you loose tons of padding material and you still risk the device shifting around in the box. That said, not my best work so I could see how you can get some damage, just not that damage...

I wouldn’t rely on bubble wrap for that sort of thing. Needs some polystyrene with cut outs for sticky outy bits then bubble wrap around that. Need to support the main mass of the unit and make sure that any impacts are absorbed by that rather than smaller parts.

230 items sent here. Zero broken.

Thats precisely what I do, I also use the moulded polystyrene right angle lengths that you get  at the corners of appliances, or flat packed furniture  and use that at the vulnerable ends of equipment and I have sent boat anchor type of oscilloscopes by couriers on many occasions and likewise, still yet to have anything damaged in transit. I keep boxes and bags full of packing peanuts in the garage and use those to fill any space around anything, and I ram them in tight to make sure that equipment does not have any wriggle room in the outer carton. Then I close the carton, again ramming peanuts in and then I tape the carton closed and run tape around the carton twice at each location, and I do that usually if the carton is about 400mm plus on its longest side at 3 locations to re-enforce it, at least once on its shortest side and also at each edge to completely seal it up. I have comments like the parcel would have stood up to a nuclear blast etc left in feedback, I also photograph the packing process at various stages to use in evidence should I ever get a complaint of damage.

[tggzzz]

Yes, unfortunately Britain's art schools managed to turn out almost a complete two generations of the former as the "YBAs".

Ah yes I got a photo of one of those artists at work at Colchester Zoo about a decade ago:

I admire the YBAs' ability to separate money from fools.

That’s why I got into software. 

My aim was to separate intelligent people from their money, which is probably more difficult and definitely more satisfying.

Smaller market though

Got to be honest here but the intelligent folk I know don’t have a lot of money to spare. They either gave it away, couldn’t be coerced into producing much of it by the usual cogs or are trying to hold onto it so field an upcoming shit storm.

... Or employed by honest companies. Such companies and people do exist, despite appearances.

[bd139]

I haven’t found one yet.

[tggzzz]

I haven’t found one [honest company/person] yet.

You are in FinTech, so that is very plausible.

[bd139]

Correct. I also worked in defence, web design, analytics, online gaming and media. Total shit shows 

[mansaxel]

Correct. I also worked in defence, web design, analytics, online gaming and media. Total shit shows 

I've been audio engineer, conslutant, morgue cleaner, DNS admin (cctld), university network wrangler, public service radio network wrangler, armed forces network wrangler, and now am trying my hands in a public service TV network wrangler rôle.  I've been running BGP for 20 years, in a bunch of different ASen.

Of these, I think armed forces and public service media were the least shit shows. The defence industry can teach Hirudo medicinalis
 a few tricks, though. After online gaming, fintech and vulture consulting, one of my least favourite industries.

[xrunner]

Definitely. 

Oh posting Pink Floyd videos I wanna play too! 

[Saskia]

some Mafiamarket Mafiosi (their department head) just offered me an 800 pesos discount on a Canon RF 15-35L 2.8 lens ...
Offer valid until tomorrow. FFS ...

[tggzzz]

Correct. I also worked in defence, web design, analytics, online gaming and media. Total shit shows 

I've done low-noise opto/analogue, semi-custom ICs, general digital hardware and software, PHY/MAC networking, telecom systems (cell performace and PAYG finance), WLANs before 802.11, and other stuff.

The defence people I worked with (in an agency that didn't exist) were very smart.

Never worked in gambling; I decided I would never work for the mob.

Media? Only BBCWild photos, and that (1999) was a good time to be in that area, since we had to invent everything (business and tech) ourselves[1]. The biggest framework-like-thing around then was SOAP, and I decided to avoid that on the basis that RPC over HTTP completely ignored the web's characteristics. Instead I invented a web-based REST-lite interface.

My "analytics" was solely creating models to try to work out which mobile phone cells were acting strangely. The network operator we worked with were a pretty good and open bunch.

Web design is something I avoided like the plague; other people can play with coloured pixels.

Overall, most of my clients were engineers - just as I wanted.

[1] and my daughter got to hold a Gromit when Aardman came and put on an "exhibition".

[bd139]

Defence folks are smart, but lack ethics on a level unapproachable by even fintech I found.

I did BBC for a bit (Naturewatch) and angered Bill Oddie once. That was my only claim to fame I think 

Another fine image from my daughter's school; Umbrella Corporation's evangelical division:



Now Umbrella Corporation were honest employers. No lies about what they were all about. Straight up honest bastards.

[Specmaster]

I'll just leave this here and lets see what comments it gets as some people I think, don't think that Brymen meters are as good as I do.

[Saskia]

all those engineers, I feel naked (yeah, I bet you wanna ...)

Mostly lingos at school ... Latin, Greek, English, French, Russian ...
first job in one of those non-existent 3 letter orgs in undisclosed activities. During that time trying to cope with Mathematics and computer science while running an import biz at the side. After "2 stints" went to university and tried to pull my act together. Switched majors to neuro/clinical psychology with a cs minor.
Had huge personal mishap (my "stepfather", the one that inofficially adopted me ...) died of pancreatic cancer a day before my intermediate exam for the diploma. Did miserably during that exam, but the profs decided to give me a break and wave me thru. 2nd blow with personal life breaking completely apart and childhood trauma coming thru, major depression. Nevertheless got a job offer at a large bank for running a futures settlement system for large accounts, my first halfway well paying job at 75 pesos/hour. Got fairly good at that and got an offer from IBM which I could not refuse. Spent 2.5 years at the kernel /parallel computing support in Mayence, then got another offer to which I jumped (T-Systems for a large german bank). During that time, depression resurfaced. Was headhunted by a pharma company and went to their research site. Got treatment for depression and was able to pull myself out of the shit. However at tremendous personal cost (divorce, about 500 000 pesos, all my savings, lost).
Pulled myself together and rebuilt my life, diversifying my interests and working my butt off. Married hubby.

Landed here.
Could be worse.
Not much experience in electronics apart from fixing the occasional device (e.g. Pinball machines), but shitloads of experience in computers, servers, integration.

Oh well.

[Robert763]

So after a hard day at work I was able to get back to the 2022E. The shorted electrolytic is a 220uF 16V 85 deg C, 0.2" pitch radial but quite dumpy (short). Most modern ones are 0.1" and tall. Quick look in the parts black hole turned up a 470uF 25V 105 deg C one a bit taller but fits under the screening lid. Yes it's more than twice the capacitance but it's LF supply decoupling for a VCO with a 100R resistor either side so won't be an issue. Quick check showed it worked. Next task was to find where the 40+ screws that came in a bag were suposed to go . Found homes for them all. Most of the attenuator screen cover screws were out and took a while to find were the last 4 went - front and rear panels. So full test, including all attenuator sections and it is all working well.

can't decide if I will keep it or not. I don't need another RF generator, bu had forgotten how small they are. Trouble is I might start getting brown Marconi TEA I've already got a 2442 26GH counter.
 

[Specmaster]

Stripping down the Avo to see what the damage is and not liking what I have so far found, it may be OK once I have repaired the missing track with a jumper wire and thoughly cleaned inside. The cutout has freed itself now, not sure if it will stay closed or not when it is reassembled. The meter reverse switch appears to welded together, further investigation required here. The plastic cover that goes over the meter movement has been broken for a while and hence allowed dirt inside the movement, needs to be removed. Discovered fine pieces of fine wire inside the air gap of the meter movement. I think I have been able to extract this and the meter pointer is less sticky as a result.-   


Flash over behind switch board


Range resistor board burn


Close up of resistor board burn


Moving coil air gap


Meter reverse switch


Cutout contacts opened


Meter brackets burnt behind resistor board                                                                                                                                                                                                             

[mansaxel]

Defence folks are smart, but lack ethics on a level unapproachable by even fintech I found.

By defence, do you mean industry or ministry?

[bd139]

industry. ministry is fine

gone down a proper rabbit hole here. I'd forgotten how much fun it was to write z80 assembly. It's so compact!

Configure stack, CTC, SIO and print hello world down the serial port. Whole damn thing is only 84 bytes. No idea if it works yet. Need to wait for the boards to arrive, possibly fix them, find and program an eprom and debug it. 

[tggzzz]

industry. ministry is fine

gone down a proper rabbit hole here. I'd forgotten how much fun it was to write z80 assembly. It's so compact!

Yeah, but the opcode map is full of holes. Well, not holes, more like gaping chasms in between the mesas. And those holes (ought to) contain the instructions you would like to use.

[Specmaster]

industry. ministry is fine

gone down a proper rabbit hole here. I'd forgotten how much fun it was to write z80 assembly. It's so compact!

Configure stack, CTC, SIO and print hello world down the serial port. Whole damn thing is only 84 bytes. No idea if it works yet. Need to wait for the boards to arrive, possibly fix them, find and program an eprom and debug it. 

Thats why the Sinclair ZX Spectrum could do so much with its 16K memory, I have the 48K one and I was running a massive database on it. It was written by an ex electrical contractor called John Campbell, who later formed Campbell Systems was writing the database not only for the Spectrum, but also the Amstrad PCW and also PC's. Operating out of the Loughton Seed Bed Centre by the Bank of England printing works.

[Cerebus]

gone down a proper rabbit hole here. I'd forgotten how much fun it was to write z80 assembly. It's so compact!

Configure stack, CTC, SIO and print hello world down the serial port. Whole damn thing is only 84 bytes. No idea if it works yet. Need to wait for the boards to arrive, possibly fix them, find and program an eprom and debug it. 

Talking of old computer rabbit holes, my simulated Multics dps8 now has three days continuous uptime under its belt. 

[Kosmic]

Well, I decided to do like everybody and bought a NanoVNA 



Ordered the SAA-2N which is a NanoVNA V2 made by Hugen with a 4" screen, metal enclosure, internal battery and Type N connectors. I decided to go with this one because of the nice Type N connectors and the supposed high quality of the calibration standards.

I was definitely not disappointed with the connectors, standards and cables. Cables are really good quality and connectors feel really good.

So first test, this is a 2.4GHz band-pass filter.


For comparison the same filter but measured with the AdalmPluto + Satsagen


Now I could show you how it could be used to do more boring RF stuff, but decided to show you something a little bit different. Can it be used as a LCR meter ? 

So, first thing first, the the NanoVNA need to be calibrated. I added some adaptors and came up with my own ghetto calibration standards 

first, Open calibration.


Now Short.


Load 


and finally through.


And now some capacitors measurement. All capacitors were measured at frequencies 10kHz to 1MHz in a series arrangement. The NanoVNA V2 can be set to 10kHz but results are kind of flaky under 30kHz.

The first one is a 10nF cap. On my real LCR meter, this cap read 10.03 nF at 100kHz. I get around 10.233 nF on the NanoVNA.



Now 100nF. This one should be around 102.11 nF at 100kHz. 101.36 nF with the NanoVNA.



Finally 1uF cap. Reading 847.22 nF at 100kHz on the real LCR meter. 738 nF on the NanoVNA.



Conclusion, it's working relatively well on the nF range. And it's really interesting to see the capacitance changing over frequency. When you reach 1uF the frequency is too high and the result are not super accurate. I also tried in the pF range but I think my calibration setup is failing me and it was not super conclusive.

[mnementh]

Working on a TDS784D. Decently bright display (sucks by modern day standards but for the series and the age not terrible...). All channels work. Off course, SPC doesn't. Not the first time I tangoed with these so I proceed with all haste to excavate the hybrids. Which are, I'm sure, marvels of black magic RF engineering but they also suck donkey balls to work on. Sure enough, one cracks while getting it out. Measuring relays yields at least one dud (4 ohm resistance) and a few doubtfulls.

Now the fun really starts. I have attempted to repair these in the past, with limited success. Long story short: some of the pins are not accesible by soldering iron. Using the hot air gun has, thus far, always resulted in the relay and its neighbours melting before I could make it "stick". The plan was to make an attempt with a hotplate and/or chipquick low temp solder. As I don't have a hotplate (yet): chipquick + hot air it is.   

Removing the relay is not the issue (cut the legs). Cleaned the pads of old solder after that. Applied some of the special flux to the pads; applied the solder. Observation: it doens't flow nearly as nice as normal paste. Has a tendency to "tear". Wetted the relay as well for good measure, more flux applied.

First attempt: as the solder offers less visual clues versus normal, I pick up the board and the relay slides off the board. Not yet cured.

Second attempt: better. But the least accesible leg is up in the air.      Pressing the relay down a bit while applying hot air seems to have done the trick:      Pretty it ain't but it'll do...

I once replaced all the relays on these hybrids. Used a homemade hotplate, just a large resistor (similar to this poor one: https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/msg3278930/#msg3278930).
Desoldering worked just fine, once the ceramic is hot enough, lift them off. Soldering the new ones was somewhat more problematic, in the end it worked.

There are aluminum PTC heater preheating plates sold all over AliEx for soldering/desoldering PCBs with large arrays of LEDs on them. I don't know what the elements are repurposed from, but they're dirt cheap:https://www.aliexpress.com/wholesale?catId=0&initiative_id=SB_20201023191900&isPremium=y&SearchText=LED+BEAD+DESOLDERING

I picked one up to make a free shipping order from a vendor; I posted in here about it at the time. Because it uses a PTC element, it self-regulates thermally to an extent.

mnem
 

[mnementh]

Well, I decided to do like everybody and bought a NanoVNA 

(SNIP)   

Conclusion, it's working relatively well on the nF range. And it's really interesting to see the capacitance changing over frequency. When you reach 1uF the frequency is too high and the result are not super accurate. I also tried in the pF range but I think my calibration setup is failing me and it was not super conclusive.

Looks exactly like the kit I ordered from Bang-em-good. Even down to the crooked N-connectors... 

I went with bg because they offered a fair price, and I had some affiliate points to burn; brought total cost of that and the Tiny SA down to (goes and looks) US$128. Oh yay! They're showing shipped!  I might actually see them by Christmas! 

Hope mine resolves as nicely as yours! 

mnem

[mnementh]

Y'all may have noticed that the ol' TinkerDwagon hasn't been in here rousing the rabble all day...^*

   

That's because he done wents on a road trip.

I met with fellow TEA member  cyclin_al to trade off some of those Dell server PSUs I've been buggin' y'all with for some TE (which I'll post pics of tomorrow, I think) but mostly to chew the fat and have a burger and scope out some of the local color, what with the fall foliage and such.



We met at The Iron Rooster just outside of Madoc, ON; a little town in the boonies aboot halfway between where he lives and Toronto. And did we ever talk... we talked the ears off that Iron Rooster; we were there for over 3 hours!

The food was great (had one of the best burgers I've eaten since my last trip to Nawlins), the stories were good, (short version: bd isn't a cynic, it's like that for everyone; everything "corporate" touches turns to multifaceted shit and the human race really is doomed ) and this place we picked mostly just because of the name... turns out it is actually a destination spot for Biker rallies and there were like 4 different groups... easily 30 or 40 people... there at the same time we were. 

   

AND they had a little motorcycle museum... a dozen or so vintage motorcycles in a mock showroom... and we got to look and touch (gingerly) and take our pics as evidence of the meetup. Excellent experience all around!

Just more proof of the great people who congregate in this little corner of the internet; even those from the Great White North, ehhh....?!?

Oh... and on the way home, I had me one of those You might be in Canada if... moments:



 

mnem
^* BTW, I noticed that still didn't stop y'all from producing 4 pages of posts...