Test Equipment Anonymous (TEA) group therapy thread

[tautech]

My current distraction... 

mnem
Caffeine levels dangerously low... must stop for refill...   

   3D Web Viewer

Currently printing. Lots of print & trial fit fettling with the model to get the body so it fits the socket in the scope properly.

mnem
I do hope this is the last iteration...

Somewhere…….. I think in the DIY SPL2016 thread is the measurements for the PCIe plug.

Yeah here:
https://www.thingiverse.com/thing:4784443

[mnementh]

Nawww, man... I went balls-deep on this one. Take a look at the 3D Model; I made the body such that the outer shell goes all the way down to the PCB, not just to the socket. Full 25mm depth of insertion, and fitted "just so" that any lateral stress is applied to the case of the scope, not the socket.

I figured if I was gonna bother, do it right and share with my fellow TEAs.

mnem
Pay it forward.

[AVGresponding]

- A very strange key for electrical cabinets. Three of it's four sides are like nothing that I've ever seen. Usage for electrical cabinets is stated by former owner.

Now I have definitely seen one of those before, but I can't remember quite where. I'll ponder it...

I carry a similar one for work. The top one is for modern standard cabinets, Sarel, Hager, etc etc, the right side and bottom ones may be for vandal resistant light fittings, idk about the left one. Some local/older variant of the same I should think.

[bd139]

I had a summer job at university stuffing boards with one of those bloody things . I lasted about a week before they promoted me much to the disgust of people who had been doing it for 30 years.

Presumably you were sufficiently incompetent at board stuffing.

I was told I was affecting team morale. I learned a lot about politics and competence in those 6 weeks.

Bringing people to the understanding that they aren't doing things as well as others can is a traditional problem. The only work around is to only hire people that will automatically and enthusiastically adopt best practices.

Recruiting such people requires skill and (in the short term) courage.

The trick is to leverage this to the point you are irreplaceable in a market vacuum. That’s roughly my situation now 

[tggzzz]

I had a summer job at university stuffing boards with one of those bloody things . I lasted about a week before they promoted me much to the disgust of people who had been doing it for 30 years.

Presumably you were sufficiently incompetent at board stuffing.

I was told I was affecting team morale. I learned a lot about politics and competence in those 6 weeks.

Bringing people to the understanding that they aren't doing things as well as others can is a traditional problem. The only work around is to only hire people that will automatically and enthusiastically adopt best practices.

Recruiting such people requires skill and (in the short term) courage.

The trick is to leverage this to the point you are irreplaceable in a market vacuum. That’s roughly my situation now 

I was lucky enough to have, in most but not all cases, found companies where I could breathe freely.

Vacuums, suck, by design.

[dl6lr]

5245L report:

Happy. Next step is to adjust input gain. Are the card edge connectors unobtainium? A lot of work is impossible unless cards are on extenders...

No, they are available here: https://www.digikey.de/de/products/detail/edac-inc/307-030-500-202/107614

Fun fact: I orderd them on 2022-03-15 and they were €4.03 each...

I tried to make my own easy extender boards but I haven't ordered them yet. Current design is connected both sides with vias (as used in the 5245L), but maybe I will isolate both sides so they can be used with full 30 pins too. Test points and holes for eyelets. Will gladly give you the KiCad project (its only drawn with the PCB editor).

[bd139]

Ooh capacitor lot arrival. This is better than I was expecting. These are all top notch ones including high voltage coupling capacitors, milspec ceramics etc and all useful values 

[grizewald]

... CA accelerator is acetone ...

No, acetone is not an accelerant for CA polymerisation. It is often used as a solvent for the actual accelerator - as is hexane - but the accelerant is generally either an amine such as N,N-dimethylbenzylamine, N,N-diethyl-toluidine or N,N-dimethyl-p-toluidine, or a disulphide such as dibenzodiazyl disulphide, 6,6-dithiodinicotinic acid or 2,2-dipyridal disulphide. Calixarene compounds can also be used to assist polymerisation with acidic items to be bonded such as wood, leather and paper. There are more accelerators and the choice of which is used depends very much on the application. Some are unpleasantly toxic.

CA accelerator mixtures may contain acetone, but acetone itself is NOT a CA accelerant.

Thanks for the correction; looks like lately I'm blind:

You're not blind! It's where you download the MSDS from which makes the difference. In some countries, the manufacturer does not need to detail every chemical used in a product and can hide these chemicals as "trade secrets" or under generic terms. Often, it is the relative volume of a chemical which determines whether it must be listed in a MSDS or not. Have a look at the two attached MSDS for the Loctite "SF 7452" accelerator. In the US version, they list the composition as "acetone and fragrance". In the other MSDS for the same product, but for a market with more stringent disclosure laws, the composition is listed as "acetone and N,N-Dimethyl-p-toluidine". Listing N,N-Dimethyl-p-toluidine as "fragrance" is comical! Fragrance in acetone? 

To start the process of polymerisation in cyanoacrylates, the presence of a slightly basic or nucleophilic compound is required, most commonly water. However, in the cases where the thickness of the CA layer prevents water from gaining access past the surface of the initial polymerisation, or where the surfaces to be bonded are acidic in nature, an accelerator is needed. Acetone is neither basic or nucleophilic and therefore cannot have the properties that an accelerator needs. What it does have is the ability to evaporate quickly which is why it is used as a solvent for the actual accelerator. So when you apply the accelerator, the solvent (acetone, hexane or similar) delivers the accelerator to the areas to be bonded and then rapidly evaporates, leaving the accelerator behind, nicely distributed over the areas and ready to do its job.

If you want to get a better understanding of cyanoacrylate chemistry, here's a document which will help: https://scitechconnect.elsevier.com/wp-content/uploads/2014/07/Reactive-Polymers-Fundamentals-chap13.pdf
 

[mansaxel]

5245L report:

Happy. Next step is to adjust input gain. Are the card edge connectors unobtainium? A lot of work is impossible unless cards are on extenders...

No, they are available here: https://www.digikey.de/de/products/detail/edac-inc/307-030-500-202/107614

Fun fact: I ordered them on 2022-03-15 and they were €4.03 each...

I tried to make my own easy extender boards but I haven't ordered them yet. Current design is connected both sides with vias (as used in the 5245L), but maybe I will isolate both sides so they can be used with full 30 pins too. Test points and holes for eyelets. Will gladly give you the KiCad project (its only drawn with the PCB editor).

Very cool.

I'd love to get the project files. Many, but not all, of the connectors are bridged (joining both sides of the connector), so I believe that isolation is a Very Good feature. I'll work a bit on my queue of JLCPCB orders and try fitting it in.

[med6753]

The trick is to leverage this to the point you are irreplaceable in a market vacuum. That’s roughly my situation now 

 

[BU508A]

The trick is to leverage this to the point you are irreplaceable in a market vacuum. That’s roughly my situation now 

 

You, when you were MUCH younger? 

[med6753]

The week long heatwave broke in spectacular fashion last evening with damaging severe thunderstorms which resulted in numerous trees and power lines down. The local utility is currently overwhelmed with thousands of customers still without power this morning. One phase on my road is currently out with many residences beyond me in the dark. Luckily my power stayed on. And luckily by the time the storms arrived here they had lost much of their punch. But just west of me got hammered pretty bad.

For the first time in a week the A/C is off and the windows open.       

[med6753]

You, when you were MUCH younger? 

No. This was me. 

[Neper]

For the first time in a week the A/C is off and the windows open.     

We're waiting for a cold front to arrive in the early evening. Doesn't look too dramatic on the radar. Won't change much on the inside temps as our walls are over 20" of solid brick and take days to cool down.

[nixiefreqq]

- A very strange key for electrical cabinets. Three of it's four sides are like nothing that I've ever seen. Usage for electrical cabinets is stated by former owner.

Now I have definitely seen one of those before, but I can't remember quite where. I'll ponder it...

I carry a similar one for work. The top one is for modern standard cabinets, Sarel, Hager, etc etc, the right side and bottom ones may be for vandal resistant light fittings, idk about the left one. Some local/older variant of the same I should think.

its been a long time.  but my recollection is that on subway and el trains the conductor had a key like that hanging on a lanyard.

[dl6lr]

You, when you were MUCH younger? 

No. This was me. 

You have to rotate your HUE CONTROL knob a little to get a more blueish tint...

[BU508A]

You, when you were MUCH younger? 

No. This was me. 

You have to rotate your HUE CONTROL knob a little to get a more blueish tint...

You mean, like this?



 

[dl6lr]

I'd love to get the project files. Many, but not all, of the connectors are bridged (joining both sides of the connector), so I believe that isolation is a Very Good feature. I'll work a bit on my queue of JLCPCB orders and try fitting it in.

Ah, I see: A6 bridge rectifier seems to be the only connector with 2x15 contacts. It uses contacs 1..15 and A. Good catch, will change the layout accordingly. Do you know if A is on the opposite of pin 1? And then they go on with B, C, ...?

[Neomys Sapiens]

- A very strange key for electrical cabinets. Three of it's four sides are like nothing that I've ever seen. Usage for electrical cabinets is stated by former owner.

Now I have definitely seen one of those before, but I can't remember quite where. I'll ponder it...

I carry a similar one for work. The top one is for modern standard cabinets, Sarel, Hager, etc etc, the right side and bottom ones may be for vandal resistant light fittings, idk about the left one. Some local/older variant of the same I should think.

The top one is indeed obvious, as I have several of similar cruciform keys which combine this one with the usual square and triangular forms. The stepped ones right and bottom have the same hole than the top one. The left one combines a 7mm inside square with the tiny 'ears'.

[mansaxel]

I'd love to get the project files. Many, but not all, of the connectors are bridged (joining both sides of the connector), so I believe that isolation is a Very Good feature. I'll work a bit on my queue of JLCPCB orders and try fitting it in.

Ah, I see: A6 bridge rectifier seems to be the only connector with 2x15 contacts. It uses contacts 1..15 and A. Good catch, will change the layout accordingly. Do you know if A is on the opposite of pin 1? And then they go on with B, C, ...?

Is it different than the numbering on the connector?

https://files.edac.net/edac/content/series/og/English/EDAC%20307%20357%20Series%20Card%20Edge%20Connectors%20English%20Ordering%20Guide.pdf

It says 1 - A, 2 - B, 3 - C and so on; skipping "G" and "I" for Reasons, one assumes...

[Cerebus]

- A very strange key for electrical cabinets. Three of it's four sides are like nothing that I've ever seen. Usage for electrical cabinets is stated by former owner.

Now I have definitely seen one of those before, but I can't remember quite where. I'll ponder it...

I carry a similar one for work. The top one is for modern standard cabinets, Sarel, Hager, etc etc, the right side and bottom ones may be for vandal resistant light fittings, idk about the left one. Some local/older variant of the same I should think.

I knew I'd seen that somewhere. Those in particular were the ones that stood out and were tickling my ineffective memory; which in one corner was saying "London Underground", and indeed that was where I'd seen them. Now I can relax and stop letting it niggle me. If memory serves, the left one fits a keyswitch.

[med6753]

My offer to show how I re-capped an hp 5248L PSU back in August 2020 has generated an interest and a request for pictures on how I did it. So I pulled out the counter this morning and took some new pictures. The capacitors that were replaced are C4, C6, C7, C8, C9, and C10.

The original cans are riveted to the chassis. I was able to keep them all in place and work around them.




On these 2 cans I did have to drill out one rivet each so a terminal strip could be installed on the opposite side.



I used existing hardware where possible to install a terminal strip for the replacement capacitor.




This is the area where I had to drill out 2 rivets to install terminal strips.




Since I had to counter apart for pictures I figured I might as well give it some power up time. After about a half hour of settling for both the reference and counter it's within 1 or 2 Hz. But this counter has the loudest and most annoying fan of any of my other TE, including the Tek 500 series scopes.

[grizewald]

And so the job is finished.



All the post clamps are now fully cured. The inserts had all been previously treated with Dexoit 100% solution, run through the ultrasonic cleaner with a detergent solution then rinsed and dried before being glued in their housings. Today I finished cleaning all the posts on the resistors, first with Deoxit and then with a toothbrush and detergent solution before rinsing and drying. Finally, I gave each insert a drop of Deoxit gold on the threads and a thin layer of the same was applied to the posts and inserts on the mating surfaces.
I also cleaned the tops of the resistors with some detergent solution to get rid of years of dirt and oil which revealed that what previously looked like "1982" on the 1 ohm resistor was, in fact, 1962. So the 1 ohm is a full 60 years old!

A very satisfying weekend's work. Hopefully, I'll be rewarded with three stable and predictable standards once I can characterise them.

[Vince]

TV REPAIR

OK I knew it was too good to be true, it was going too well, I should have been wary....

Just started buttoning it back up. Screwed the two metal brackets that hold the plastic feet, back onto the chassis.
Re-installed the speakers.

Quick check to see if I can get sound from it.

TV is entirely controlled via the IR remote, there are no buttons on the TV itself.
Guess what ? Yes, the fucking remote doesn't work, can't operate the TV !!!

Batteries are good. Pointed the IR LED to my camera and I can see bright light coming out of it when I press buttons, so the remote works.

Yet the TV does not respond at all !

Yes, the ribbon cable connecting the IR receiver to the digital board, is plugged in properly, but no joy.

So that means I did all that work for nothing and I will probably not even get back the 14 Euros I spent to buy the new LED strips !

That's why I hate consumer stuff... I just hate it with a passion !!! 

[Specmaster]

Ooh capacitor lot arrival. This is better than I was expecting. These are all top notch ones including high voltage coupling capacitors, milspec ceramics etc and all useful values 

Wow, also pre-sorted as well, I had visions of you sitting at your table or desk in the early hours of the morning doing sorting, just like Vince does