Test Equipment Anonymous (TEA) group therapy thread

[Neper]

...my Little Bag of Dirty Tricks™

Would you mind giving us a little guided tour of that bag?

[AVGresponding]

Discord is currently heading down the tracks like a driverless steam engine with the throttle jammed open and for some reason someone has set the cab on fire and painted a winking smiley face on the front of the firebox

[mnementh]

...my Little Bag of Dirty Tricks™

Would you mind giving us a little guided tour of that bag?

Yes, I would. There are certain items in there that are... not for public consumption. 

mnem
"That's allright; my secrets guard themselves..."

[Cerebus]

...my Little Bag of Dirty Tricks™

Would you mind giving us a little guided tour of that bag?

Best not. You're still too young to find out about certain things...

[Zoli]

The cure is to buff it down with very fine sandpaper (like 800-2000 grit); I use this fingernail buffing board. Yeah, I know it's pretty horrible looking; it's prolly older than my daughter.

For silver tarnish removal an eraser does wonders, without removing any of the underlying silver.

You want to remove some of the silver, to remove the divot (wear crater) and make the contact flat again. As you can see in the pic, there's more than enough material to do this several times. This leaf spring is made of thin hardened brass, so pretty fragile; trying to rub it with a pencil eraser hard enough to remove anything is much more likely to mangle it than do any good.

mnem
 

Case-by-case use; you don't want to use sandpaper on two flat surfaces, the chance to FUBAR is too big.

[Neper]

Here's my no longer secret weapon. A typewriter eraser. Flat enough that it will only erase in one line and harder than ordinary erasers.

Great for cleaning PCB contacts and such like.

The missing piece has broken out because it has become brittle over the years. It's certainly 50 years old.  Had to take a photo as I couldn't find one online.

[ Specified attachment is not available ]

[BU508A]

While I was looking for some scopes on ebay, I stumbled over this abonimation abomination:

https://www.ebay.com/itm/394152027065



    

[xrunner]

200 kHz BW? Yea what a POS. Should be at least 300 kHz for that price. 

While I was looking for some scopes on ebay, I stumbled over this abonimation:

https://www.ebay.com/itm/394152027065



    

[bd139]

Oh great now I'm going to get nightmares tonight 

[mnementh]

The cure is to buff it down with very fine sandpaper (like 800-2000 grit); I use this fingernail buffing board. Yeah, I know it's pretty horrible looking; it's prolly older than my daughter.

For silver tarnish removal an eraser does wonders, without removing any of the underlying silver.

You want to remove some of the silver, to remove the divot (wear crater) and make the contact flat again. As you can see in the pic, there's more than enough material to do this several times. This leaf spring is made of thin hardened brass, so pretty fragile; trying to rub it with a pencil eraser hard enough to remove anything is much more likely to mangle it than do any good.

mnem
 

Case-by-case use; you don't want to use sandpaper on two flat surfaces, the chance to FUBAR is too big.

What are you talking about? Not on two surfaces; just one. The point is to make the contact flat again, as it's had a hole worn in it by the other contact which is a stamped metal chisel point. We're talking 0.10-0.20mm here.

Here's my no longer secret weapon. A typewriter eraser. Flat enough that it will only erase in one line and harder than ordinary erasers.

Great for cleaning PCB contacts and such like.

The missing piece has broken out because it has become brittle over the years. It's certainly 50 years old.  Had to take a photo as I couldn't find one online.

Your eraser would just tear the thing up. PCB is 100x more durable than these tiny paper-thin bits of spring brass. Y'all are operating under the assumption that it's just tarnish you're removing. You need to make the surface flat again otherwise it doesn't make reliable contact. I've tried cleaning switch contacts like these with Tarn-X followed by distilled water; that doesn't restore reliable contact. Refacing the switch does.

This isn't the "PCB and fingers" type switches in a Tek attenuator... removing a little metal is perfectly harmless, and is in fact the correct way to fix the problem.


mnem
Next, all y'alls will be givin' me a rash of shit aboot boring out a engine to do a overhaul.

[mnementh]

Oh fuck me... Ever since I finished my Nuking the Mouse writeup, I've been searching all over my shop for my little container of 0.100" socket header... even while I was in the Discord... and all this while they've been at the bottom of my larger container of assorted 0.100" pin headers...   

mnem

[Zoli]

The cure is to buff it down with very fine sandpaper (like 800-2000 grit); I use this fingernail buffing board. Yeah, I know it's pretty horrible looking; it's prolly older than my daughter.

For silver tarnish removal an eraser does wonders, without removing any of the underlying silver.

You want to remove some of the silver, to remove the divot (wear crater) and make the contact flat again. As you can see in the pic, there's more than enough material to do this several times. This leaf spring is made of thin hardened brass, so pretty fragile; trying to rub it with a pencil eraser hard enough to remove anything is much more likely to mangle it than do any good.

mnem
 

Case-by-case use; you don't want to use sandpaper on two flat surfaces, the chance to FUBAR is too big.

What are you talking about? Not on two surfaces; just one. The point is to make the contact flat again, as it's had a hole worn in it by the other contact which is a stamped metal chisel point. We're talking 0.10-0.20mm here.

Relays, contactors - most of them has parallel contacts, not round ones. I've fixed quite a few with the eraser on the top of the BIC disposable mechanical pencil.

[mnementh]

What are you talking about? Not on two surfaces; just one. The point is to make the contact flat again, as it's had a hole worn in it by the other contact which is a stamped metal chisel point. We're talking 0.10-0.20mm here.

Relays, contactors - most of them has parallel contacts, not round ones. I've fixed quite a few with the eraser on the top of the BIC disposable mechanical pencil.

"Most of them" is not these micro-switches. All you have to do is look at the pics to see that's not the case here. What you're going on about simply is not applicable in this case, I'm sorry. And in hundreds of mice I've fixed this way, I've never seen switches that weren't identical construction inside.

Think of it like a cheap rocker switch (the kind where one contact is just a rolled edge of brass) that has a pit burned in the silver on the contact arm. An eraser is not going to fix that. Just like with a burned contactor.

Cheers,

mnem
*toddles off to nuke a monitor*

[mnementh]

Oh great now I'm going to get nightmares tonight 

mnem
"There are worse things that stalk the night than demons and monsters... I am one of them."   

[salvagedcircuitry]

Brothers and sisters, we need to band together and unite as one against this inhumanity. 
I just received this in the mail the other day and I have been losing sleep at night. look at this butchery, this mockery, this abomination.
We need to unite to fend up against this stain on our trade.
No more oscilloscope dumpsters! This should be declared a crime against humanity.
Who should we contact for crimes against test & measurement?
Surely not PETA. NIST? The International Bureau of Weights and Measures? The Loveland Standards Lab? The lab coats of Beaverton? Our German friends in Munich?
It's gone too far. Look at it. The red and black controls are reminiscent of the Tek 540 series. 
Realtors need to know that all labs are scared no matter the gear. Hands off our probes!

[xrunner]

Surely not PETA.

Yes they can help - People for Ethical TEA Abandonment. 

[Zoli]

What are you talking about? Not on two surfaces; just one. The point is to make the contact flat again, as it's had a hole worn in it by the other contact which is a stamped metal chisel point. We're talking 0.10-0.20mm here.

Relays, contactors - most of them has parallel contacts, not round ones. I've fixed quite a few with the eraser on the top of the BIC disposable mechanical pencil.

"Most of them" is not these micro-switches. All you have to do is look at the pics to see that's not the case here. What you're going on about simply is not applicable in this case, I'm sorry. And in hundreds of mice I've fixed this way, I've never seen switches that weren't identical construction inside.

Think of it like a cheap rocker switch (the kind where one contact is just a rolled edge of brass) that has a pit burned in the silver on the contact arm. An eraser is not going to fix that. Just like with a burned contactor.

Cheers,

mnem
*toddles off to nuke a monitor*

IIRC, we're talkin'bout tarnishing, not burn; beside, I've meant general cleaning, not only µswitches. Glad to talk out misunderstandings.
Cheers,
Zoli

[mnementh]

Okay... you got me; well done pulling the dwagon's tail. 

I'm gonna go tinker on my prehistoric scopes now... I have my socket header, and I have a plan. 

mnem
electrons fear me.

[Brumby]

200 kHz BW? Yea what a POS. Should be at least 300 kHz for that price. 

While I was looking for some scopes on ebay, I stumbled over this abonimation:

https://www.ebay.com/itm/394152027065



    

I see:
* 200 Kmhz  in the listing title
* 200-kMHz  in a description heading
* 200 kHz  in the desciption text

The first, I'm not sure how to interpret.  The second would be 2GHz (impressive!) and the third is, at least, credible.

However, I already have a DSO138 and one of those $20 component testers ... but the case doesn't look half bad.

[Brumby]

.... and I have a plan. 

I say that as well.

I only wish they would pan out a bit more often than they do.

[Brumby]

I have also done microswitch surgery, but on a CD changer in one of those half-sized jukeboxes (that I literally, found on the side of the road.)

The result was quite successful, but not long-lived.  From your write-up, it is clear I was too gentle in my efforts.  However, having this information has given me the confidence to make a more determined effort that should yield a better lasting result ... if I could be arsed digging the thing out of the garage.

[mnementh]

.... and I have a plan. 

I say that as well.   I only wish they would pan out a bit more often than they do.

Amen, brother. 

mnem
"Life is what happens while you're busy making other plans." ~attributed to John Lennon

[mnementh]

Actually, I was thinking to make a header so I could plug the HP pod and whip leads directly into the oz2cpu scope PCB. As I said, those will probably be more than long enough for anything I'd be doing, unless I change my mind and put the scope up higher on my bench, which is pretty unlikely ATM.

I was asking about MK's project since you linked to it at the beginning of the SDS2000X thread. Not knowing what the difference is between the Siglent frontend and the HP braided cables, I'm leery of just plugging random lengths of either braided cable or micro-coax into the front of the scope without any compensation, or the wrong compensation. I saw the issues oz2cpu was having there in the beginning.

mnem
 

OK so if you already have the HP pod den go widdat !
Be aware you only need get something 1/2 clean into the LA input terminals as what's shown on the display in Digital mode bares little resemblance to the actual signal. IIRC there's discussion about this in the DIY thread.
IMO coax LA probe set compensation is likely to be pretty much an industry standard however the truth of the matter is suck it and see.
But the fact that we don't see cries that 'it don't work properly' for any of these DIY creations which points to them being fairly forgiving.

I don't have the [hp] pod yet... but they are available pretty reasonably, and sometimes you even get a few genny HP grabbits. It's trying to get a full set with the grabbits and the braided cable and not in train wreck condition that's difficult. Vince has no idea how lucky he got.     

What's pretty reasonably ?   TBH you should do the research to find the Pt#'s for the same or close LeCroy, Tek and Rigol LA PCie probes and try and pick one of them up reasonably. The grabbers are no big deal if you can get the rest of the probe complete.   https://www.aliexpress.com/item/1005001445436599.html
Just don't buy this garbage:   https://www.aliexpress.com/item/32981701765.html

I have a copy of TK's adapter PCB on the way; mostly because the BOM is: $15. Boom! Seeya! Done!

Also because the layout lends itself to my intended means of attacking the problem: solder a piece of socket header on the edge of the PCB and just plug the HP pod directly onto it.

I figured it was something I could just throw a little money at and hopefully it works as well as it did for him; otherwise, I either get the braided cable and try it that way, or I get oz2cpu's pcb made and build it with the same pod.

   https://www.ebay.com/itm/294846434318

I've shopped around and seen the HP pods going for ~$20-25 with a few grabbits; but since TK's PCB was so cheap, I splurged $35 on this HP pod which appears to be NOS and in unused condition, with all the whip leads and a full set of HP grabbits.

We'll see how it works out. 

mnem
 

[bd139]

Today i try download new firmware for my equipment, but TEK website is unavailable now...



I guess I should offer to Danaher/Fortive corp. my "System Reliability Engineer" services for their website. 

I’ve learned never to offer my IT skills to large corps. You can’t escape afterwards 

[Specmaster]

200 kHz BW? Yea what a POS. Should be at least 300 kHz for that price. 

While I was looking for some scopes on ebay, I stumbled over this abonimation:

https://www.ebay.com/itm/394152027065



    

I see:
* 200 Kmhz  in the listing title
* 200-kMHz  in a description heading
* 200 kHz  in the desciption text

The first, I'm not sure how to interpret.  The second would be 2GHz (impressive!) and the third is, at least, credible.

However, I already have a DSO138 and one of those $20 component testers ... but the case doesn't look half bad.

Agreed, the case looks reasonable enough for what it is. I always wondered how long it would be before someone managed to combine the functions of the Chinese component testers and a DSO138, both of which I have in my toolkit. This unit however goes one step further I think, it seems to also have signal generator build in as well which would make it a reasonable pocket tool, especially useful for tracing signals in a DUT (has to be less than 200Khz) and it is ideal also because it is fully floating so no risk of grounding anything.