Test Equipment Anonymous (TEA) group therapy thread

[mnementh]

Ummm.... yeah.... no. That's just an exploded dust bunny (with maybe actual human whisker shavings in it).

Sorry... I was looking at the heat-sink behind the tin-plated shield. D'oh!

Tin whiskers are a chemical decomposition; an actual crystalline growth of the tin as it oxidizes. This means that it will exhibit crystalline growth patterns (always straight lines, at oblique angles from source material), even when it appears as a filament. It does not "grow" laying flat on a plastic insulator or aluminum heat sink.

It doesn't appear as random clouds of loose whisker-like particles in varying colors; it appears as blastuloid nodules (if there is sufficient silver content) and spider silk-like filaments of light grey-to-white opaque material with associated white flakes and powder. These filaments are extremely fine... much finer than a human hair. So fine that minute movement of air or even their own weight can bend them if they grow long enough. This is the cause of the "curly" looking growths.

The stuff in bean's photo is translucent; and while the form appears similar to "silver whisker" deposits often found near high-current contactors (these form as a plasma-arc boiling metal byproduct of failing silver contact pads), it is clearly not metallic but organic or polymer.

Don't be confused by pictures of "zinc whiskers" as seen in the galvanized pipe bracket below. That is a similar process wherein the zinc "grows" on moisture in the air; this is what makes them look fuzzy. 

mnem

[med6753]

Wouldn't have that problem if they used these....



 

[mnementh]

DUH!! You need an electric razor for tin whiskers on electronics.

mnem
Like, totes obvi.  

[Specmaster]

Agreed, must avoid all kinds of moisture least it brings liquid damage into the equation 

[med6753]

At a frustrating stand still on both 465B projects. The 4x attenuator for the channel 2 switch deck is STILL sitting at JFK.  Almost 3 days now. What the hell is USPS doing or better still, NOT doing.   

The tantalum caps for the "parts" 465B seem to be stuck somewhere between the hand off from UPS to USPS. Sez will deliver Saturday but I'm not holding my breath.   

[bd139]

USPS are just the worst. 9 days from Miami to a plane for my VTVM probes. They were delivered here the day after they landed.

[med6753]

I don't usually have problems with USPS but they must be on a work slow down or something. 

[mnementh]

More budget cuts to pay for the Great Tax Heist of '17. Welcome to Chump's America.

mnem

[med6753]

More budget cuts to pay for the Great Tax Heist of '17. Welcome to Chump's America.

mnem

That reminds me of the toy RPG launcher I had as a kid. It fired large soft plastic RPG's. That met it's doom when I hit my Sister in the eye.    My father broke it in half.   

[bd139]

Decided to try and fix my T12 iron this afternoon as I need to go do some soldering outside. Narrowed it down to the handpiece going short when there's a tip/element installed. Frmph. Bloody thing.

Edit: ok the receptacle in the 9501 handpiece is knackered. The tip goes short if you push it all the way in. If you pull the tip 2mm out it's fine. Needs a new middle bit by the looks.

Edit 3: ok managed to ram some plastic down that and get it going temporarily. Then the MOSFET let go. Took that out of circuit and the controller is dead too thus I just took the fucking thing out into the back garden and did a hammer throw with it onto the garage roof down the street.

T12 is over. Looking for a 12V Antex or TCP now.

[mnementh]

Yeah; that's what I was talking about when I said there seemed to be a considerable variation in the quality of the socket depending on whom you get your FX-9501 handle from. The two I know as decent and produce reliable contact are the ones I got from KSGER's store on AliEx and the one from Aiyima.

The one that came with my bogus KSGER iWELD  "Stainless" (actually cheap chromed steel) handle from Banggood is quite a bit better than either of those; it appears to actually be nylon and cleaner molding. But no idea if you can actually get it anymore; it appears Banggood is clearing them out and no way of knowing if the ones they have now are the same, or KSGER, or some other manufacturer. And of course they couldn't care less about the thing being a complete ripoff; they haven't changed a thing in the listing even after eating a 100% refund on my dispute.

mnem
*p00t!*

[mnementh]

https://www.sciencenews.org/article/black-hole-first-picture-event-horizon-telescope

Fukkin' A-Diddy!!! 

mnem
Can I get a side of honey-mustard widdat?

[0culus]

That's the event horizon of this thread, seen across spacetime. 

[kj7e]

The first one got here, now waiting on the second unit with the dead CRT to swap out the High Stability OCXO (Option 10).  So far it appears to be in good working order 

[GregDunn]

Yay, women in STEM.

https://abcnews.go.com/US/meet-29-year-computer-scientist-wrote-algorithm-black/story?id=62331181

[0culus]

The first one got here, now waiting on the second unit with the dead CRT to swap out the High Stability OCXO (Option 10).  So far it appears to be in good working order 

Looking really nice! Can you put an external timebase on it in the meantime?

[kj7e]

The first one got here, now waiting on the second unit with the dead CRT to swap out the High Stability OCXO (Option 10).  So far it appears to be in good working order 

Looking really nice! Can you put an external timebase on it in the meantime?

Yes you can.

I forgot to add, the cal sticker is from 2015, all seals intact... well they were until a few min ago 

[0culus]

Nice! I am considering getting a GPSDO + distribution amp for my lab. Just to get everything on the same frequency standard.

[Specmaster]

Well so far it's been a mix of good and bad news for today. I managed to snag a pair of Solartron 7150 Plus 6.5 digit bench meters for a reasonable price today in auction, more on these when I collect them next week. I'm fully expecting to have to replace the mains filter on them both as they are stuffed with rifa's in a metal casing) need to investigate the options here) and see if there's better solution.

The bad news is that while trying to diagnose the problem with the A109 amp, disconnected the gate on all of the output mosfets and connected dummy loads across the speaker terminal, powered up and within seconds smoke poured out of the right hand channel mosets and toasted them. Double checked the gate leg being disconnected and they most certainly were isolated on the gates, result 2 blown Mosfets this time on the right hand channel.

This amplifier is not the best one I've ever worked on either, being a combination of TH and SMD with a rubbish service manual. The front panel is all SMD and plugs into the main board and to service it to get all round access you have screw the backplate with the main board attached to the bottom plate, in a upright position with a single screw. The front plate has nowhere to go and so I have had to resort to cable ties to keep it attached to the main board and and bottom plate. This mains that mains input board has to be removed and is free floating while connected to the mains and sits on the metal bottom plate  , so had isolate that as well. I always thought Pioneer were a good brand, rapidly changing my opinion now.

[bd139]

That’s why they’re called FETs. The noise they make 

More seriously, total bummer.  Id probably drop kick it over a fence by now.

Built a 2m slim Jim antenna this evening that worked first time. First time I’ve done anything that worked properly first time!

[0culus]

I'm looking forward to having my own place where I can play with outdoor antennas. 

[Specmaster]

That’s why they’re called FETs. The noise they make 

More seriously, total bummer.  Id probably drop kick it over a fence by now.

Built a 2m slim Jim antenna this evening that worked first time. First time I’ve done anything that worked properly first time!

I could well believe that if it was your's that it would be joining your T12 in your neighbours garage roof by now Removed all the FETS and checked them over, those on the Left channel check out OK but those on the right one, totally toasted, checked as 3 resistors, replaced with new ones which test as OK, just wondering if I should do the Left channel as well so it gets all new FETS. Time to dig out my smart tweezers to see if I can find anything with the SMD's before I pop it all back together again.

Congratulations on your Slim Jim, first time ever you built something that worked the first time, oh hell yeah, I'm not believing a single word of that 

On the T12 topic, so far I've not had any problems with mine still, but then, having 2 of them means that I really don't have to keep swapping tips as much so maybe my handles haven't worn as much, what I have noticed is though with those cheaper tips that they supply, sometimes the contact rings come undone and then they get thrown away so maybe I'll have to invest in new tips, hopefully genuine Hakko ones this time around.

[tautech]

That’s why they’re called FETs. The noise they make 

 

Built a 2m slim Jim antenna this evening that worked first time. First time I’ve done anything that worked properly first time!

Yep, there're a pretty neat and easy style to work with.
The 315 MHz one I did wasn't far off the mark first time up. 

[Mr. Scram]

https://www.sciencenews.org/article/black-hole-first-picture-event-horizon-telescope

Fukkin' A-Diddy!!! 

mnem
Can I get a side of honey-mustard widdat?

https://youtu.be/It7107ELQvY

[bd139]

Built a 2m slim Jim antenna this evening that worked first time. First time I’ve done anything that worked properly first time!

Yep, there're a pretty neat and easy style to work with.
The 315 MHz one I did wasn't far off the mark first time up. 

Yes I was quite surprised. I used 450 ohm ladder line off ebay, used 0.91 as velocity factor and 145MHz as centre frequency in http://m0ukd.com/calculators/slim-jim-and-j-pole-calculator/ and 10m of RG58 milspec feed. Chucked it on my squid pole strapped to the garden waste bin and poked it up in the air and literally flat SWR across 2m straight off the calculator measurements.   Didn't even have to adjust the feed position!

Bonus I can pick up Heathrow ATIS if I want a weather report and listen to the tower chatter.

I'm looking forward to having my own place where I can play with outdoor antennas. 

I'm going to take this out in the car and sit on hills with it. There's bugger all I can do with it locally as my new neighbour is a dick. I have to covertly do stuff after dark.