Test Equipment Anonymous (TEA) group therapy thread

[med6753]

2467B... it's all " fixed " !!! 

Can't believe it....

Well done, you've motivated me just a little further towards tackling my 2465 re-cap. My 2465 has never had anything done to it (no repair, re-cap, RIFA, re-cal), but it works fine at the moment (famous last words).

McBryce.

Bookmark this link for future reference. I won't let you fail. 

https://www.eevblog.com/forum/testgear/tektronix-2465b-oscilloscope-teardown/msg1658102/#msg1658102

[BU508A]

I cannot help myself, but this scope screen shield reminds me somehow to this:



 

[McBryce]

2467B... it's all " fixed " !!! 

Can't believe it....

Well done, you've motivated me just a little further towards tackling my 2465 re-cap. My 2465 has never had anything done to it (no repair, re-cap, RIFA, re-cal), but it works fine at the moment (famous last words).

McBryce.

Bookmark this link for future reference. I won't let you fail. 

https://www.eevblog.com/forum/testgear/tektronix-2465b-oscilloscope-teardown/msg1658102/#msg1658102

That's been bookmarked for quite a while now. I just need to find the time/motivation to start.

McBryce.

[med6753]

I cannot help myself, but this scope screen shield reminds me somehow to this:



 

That kitty Kat don't look happy at all. 

[BU508A]

How would you feel / look, if you have to wear a cone of shame? 
  

[med6753]

How would you feel / look, if you have to wear a cone of shame? 
  

Just like when I wore a catheter. 

[bitseeker]

Hello TEA community,

today I'd like to introduce a Keithley 225 precision current source which I received this week.
It is a current source with seven ranges, starting range from 10nA (with a resolution of 100pA) and going up to 10mA with a max. output current of ca. 100mA.
The 225 has been introduced in the 70's and my device is from 1979, Rev. D (printed on the PCB).
I did some measurements with my DMM 7510 and I'm impressed about the performance of the 225.
The voltage reference being used is a 1N827A  (D116). Manual can be downloaded from here (xdevs.com).

But now for the pictures:

Front, back and a detailed view of the connectors on the back.
Some writing on the back is saying August, 29th, 1979.

...

Wow, that's quite a write up and photo gallery! Makes me want to get a 225. 

[BU508A]

Hello TEA community,

today I'd like to introduce a Keithley 225 precision current source which I received this week.
It is a current source with seven ranges, starting range from 10nA (with a resolution of 100pA) and going up to 10mA with a max. output current of ca. 100mA.
The 225 has been introduced in the 70's and my device is from 1979, Rev. D (printed on the PCB).
I did some measurements with my DMM 7510 and I'm impressed about the performance of the 225.
The voltage reference being used is a 1N827A  (D116). Manual can be downloaded from here (xdevs.com).

But now for the pictures:

Front, back and a detailed view of the connectors on the back.
Some writing on the back is saying August, 29th, 1979.

...

Wow, that's quite a write up and photo gallery! Makes me want to get a 225. 

Mission accomplished!
  

[mansaxel]

Wow, that's quite a write up and photo gallery! Makes me want to get a 225. 

Mission accomplished!
  

Similarly, here, my interests got tickled by Vince having his per aspera ad astra moment with the 2467. I will own one, some time. But, I suppose I should get a decent digital scope first. (And, of course. fix my 5440, at that.) 

The ability to show slow, 0,1-2Hz or so waveforms (more like DC trend plots, actually) is something I find useful quite a lot, and that is a simple argument for a digital scope. I often find myself going to the ScopeMeter simply because it allows that.

[BU508A]

Wow, that's quite a write up and photo gallery! Makes me want to get a 225. 

Mission accomplished!
  

Similarly, here, my interests got tickled by Vince having his per aspera ad astra moment with the 2467. I will own one, some time. But, I suppose I should get a decent digital scope first. (And, of course. fix my 5440, at that.) 

The ability to show slow, 0,1-2Hz or so waveforms (more like DC trend plots, actually) is something I find useful quite a lot, and that is a simple argument for a digital scope. I often find myself going to the ScopeMeter simply because it allows that.

For this purpose, a Keithley DAQ6510 would fit the bill perfectly. 😇

Keithley DAQ6510

[factory]

Sort of TEA related for a change, failed Sprague 109D wet tant  capacitor, rectifier diode is shorted too and the acid that escaped from tant ate the track underneath. 

Had that in my first Tek 1502. Fortunately the PCBs are simple double-sided PCBs, so easily repairable.

Haven't had much time to work on this today, the board is part of the DC to DC convertor for a Tek 422 scope with the AC/DC option, thankfully the 20x D cell leak tubes are long gone.

Further investigation reveals the other diode is open circuit & the other capacitor (8.2uF) is shorted, the two rectifiers & capacitors are the voltage doubler for the -110V output.


Only managed to repair the track & fit the replacement diodes today, the original diodes were Tek 152-0061-00 100mA, 175V rated, either BAV20/21 would do, but I only have BAV19 (too low voltage) in stock, I've fitted some 1S923 (200mA 200V), Mouser claims they are fast recovery rectifiers.


David

[mnementh]

2467B... it's all " fixed " !!! 

Can't believe it....
(SNIP)
So happy I bought it, a good deal ! This scope is a keeper !! 

Obviously all of you out there with a 2465/2467 knew very well all along what my "problems" were, and were laughing in the background instead of rescuing me.

Needless to say, I hate you all deeply !!

I can't believe you let me rot that much for so long. You have no pity, not even for a fellow TEA. I am extremely disappointed.

I feel I need a 6 months TEA abstinence to rethink my membership...   

Speaking for myself, I were a bit busy IRL and most of the time had a hard time figuring out exactly  you were going on about.   

In all honesty Vince... when you get frustrated, your train of thought gets pretty erratic; trying to identify the actual point that you're trying to make can be hard as it seems to change from moment to moment. It's a bit like mental Whack-a-Mole.   

But one thing I have noticed is that, just like this time, once you settle down and actually take the deep dive into whatever you're working on, you seem to pretty quickly zero in on what is actually wrong and what part is PEBKAC error. 

Knowing this, it seemed best to let you do it your way; at least until you got so deadlocked you asked for a lifeline. Some people function best when they're lost in the woods; you might be one of those. 

mnem
"Don't follow me; I'm lost."

[mnementh]

I cannot help myself, but this scope screen shield reminds me somehow to this:



 

That kitty Kat don't look happy at all. 

mnem
At least it's not the Cone of Silence... *cringe*

[Vince]

2467B... it's all " fixed " !!! 

Can't believe it....
(SNIP)
So happy I bought it, a good deal ! This scope is a keeper !! 

Obviously all of you out there with a 2465/2467 knew very well all along what my "problems" were, and were laughing in the background instead of rescuing me.

Needless to say, I hate you all deeply !!

I can't believe you let me rot that much for so long. You have no pity, not even for a fellow TEA. I am extremely disappointed.

I feel I need a 6 months TEA abstinence to rethink my membership...   

Speaking for myself, I were a bit busy IRL and most of the time had a hard time figuring exactly out  you were going on about.   

In all honesty Vince... when you get frustrated, your train of thought gets pretty erratic; trying to identify the actual point that you're trying to make can be hard as it seems to change from moment to moment. It's a bit like mental Whack-a-Mole.   

But one thing I have noticed is that, just like this time, once you settle down and actually take the deep dive into whatever you're working on, you seem to pretty quickly zero in on what is actually wrong and what part is PEBKAC error. 

Knowing this, it seemed best to let you do it your way; at least until you got so deadlocked you asked for a lifeline. Some people function best when they're lost in the woods; you might be one of those. 

mnem
"Don't follow me; I'm lost."

I think you are right.... I am just using TEA to think out loud, it helps me solve the problems at hand...
The simple fact of airing my problems helps my neurons connect together into problem solving mode...
It's like having to take notes of what your teacher says. If I don't take notes, I don't remember what he said. If I take notes, I remember what he said, and don't even feel the need to read my notes...
So it's not the notes themselves that are helpful.. it's just the act of taking them that enables the brain to register what the teacher says 


The time base "issue" at least, must have been confusing to read about, because it was certainly confusing to me to begin with ! 

[med6753]

Sort of TEA related for a change, failed Sprague 109D wet tant  capacitor, rectifier diode is shorted too and the acid that escaped from tant ate the track underneath. 

Had that in my first Tek 1502. Fortunately the PCBs are simple double-sided PCBs, so easily repairable.

Haven't had much time to work on this today, the board is part of the DC to DC convertor for a Tek 422 scope with the AC/DC option, thankfully the 20x D cell leak tubes are long gone.

Further investigation reveals the other diode is open circuit & the other capacitor (8.2uF) is shorted, the two rectifiers & capacitors are the voltage doubler for the -110V output.


Only managed to repair the track & fit the replacement diodes today, the original diodes were Tek 152-0061-00 100mA, 175V rated, either BAV20/21 would do, but I only have BAV19 (too low voltage) in stock, I've fitted some 1S923 (200mA 200V), Mouser claims they are fast recovery rectifiers.


David

Did not realize that was the PSU out of a Type 422. That scope over it's production run had two different designed supplies. The Type 422 I did last year has the alternate design supply. I think my version is the later re-designed PSU.

Pix after re-cap.

[vk6zgo]

It seems that I was right to make up those extender cables for SC110 after all, even though there were real piggies and I really had to try hard to get my tongue at just the angle. Had I not done that, it would have been even harder to find the fault as where the actual problem was right underneath the vertical board and hidden by a screening plate

It was the emitter lead of an obsolete transistor (BF199) in the differential amplifier had fractured.  Extracted the transistor, tested OK, soldered in a resistor leg to make a replacement emitter lead, replaced transistor and then carefully soldered the remains of the fractured lead to the resistor leg and tested WHOOP, it lives on.       Now to reassemble all the boards and do a calibration check before final assembly and full photos.                                                                                                                                                                                                                                                                                                                                   

Wait... what...? You mean it didn't fracture right flush with the package...? 

Damn, Spec... you got lucky! Run out right now and buy a lottery ticket before it wears off!

mnem
*currently arguing with Frustion360*

My very first successful repair (when I was 16), was replacing an OC71 with just such a problem in a "pocket transistor radio"(back when such things were "new tech"!)

Luckily, it was a standard device----in the same time period, the Radio Workshop at my then employer was waiting months for very rare Germanium NPN transistors for one customer's radio.

Yes Virginia, there were NPN Germaniums, used elsewhere than complementary symmetry output stages--the particular radio didn't have a PNP in it!

[vk6zgo]

Yeah, that's a large part of what I wind up getting into painful recursive debates with some folks (mostly those who are even worse at math than I am... how is that possible?  ); they just can't seem to grasp the fact that every step you get away from the point the energy is created to the point work is done is an order of magnitude of loss in total system efficiency.

What's really disheartening is trying to explain to these people that this model goes all the way up to the root source of all energy on this planet, which is the sun itself. Every step we get away from using that energy directly is another step of storage in some form... and again, an order of magnitude of loss in overall efficiency. 


mnem

This is why I wonder about people who want to use electricity generated from a home solar electricity system to provide power for a HWS, when, with little effect upon the roof area available for the solar panels, they can have a solar HWS, with the solar energy directly heating the water.

Another thing is pushing high density living on the basis of energy saving by making it "closer to where people work", thus, allegedly saving energy used for transport.
 
Two things seem obvious to me:-
(1) Not everybody works in the City Centre, so they will need to travel across the City to their work.
(2) Clothes drying on a backyard line is not possible in a high rise (unless you live in Hong Kong), so each flat will be using energy hungry electric clothes driers.In the Summer, these will heat up the flats, with a necessary increase in the use of airconditioners, to further increase energy consumption, on the washing days.

OK, in Countries with no discernible Summer, & very few rain free days, outside drying may not be an option, but certainly in Australia, & many others, it is---& it is free!

[med6753]

(2) Clothes drying on a backyard line is not possible in a high rise (unless you live in Hong Kong), so each flat will be using energy hungry electric clothes driers.In the Summer, these will heat up the flats, with a necessary increase in the use of airconditioners, to further increase energy consumption, on the washing days.

OK, in Countries with no discernible Summer, & very few rain free days, outside drying may not be an option, but certainly in Australia, & many others, it is---& it is free!

Most moderately priced apartments (flats) here do not have individual hook ups for washers/dryers. A central laundry room is the norm although some have none so you must visit a laundromat. We have a laundry room here but only one washer and dryer. Combine that with inconsiderate individuals who don't promptly remove their laundry makes it sometimes a PITA.

I do most of my cooking with a toaster oven or microwave so I rarely use the stove/oven. Especially in Summer.   

[Cubdriver]

I cannot help myself, but this scope screen shield reminds me somehow to this:



 

Whoof - there's murder in those eyes!!

-Pat

[mnementh]

IN OTHER NEWS: Thrift Haul No 227:




Today's thrifting run was productive but a wee bit more expensive than usual.  Picked this up for $55 brand-new in sealed box as it had a huge hole in the side of the carton; very careful inspection with my flashlight showed no damage, so I took a chance on it. This thing is supposed to like do EVERYTHING; Dehydrator, Convection oven, Toaster Oven, Air Fryer... even proofing bread! It's sortof like those ovens at Subway that toast your sandwich in 30 seconds, only for the home. Since I'd been shopping air fryers already, I decided that was little enough $$ to take the plunge.

My first test was on some cold pizza; quartz IR tube heating elements are glowing orange in like 10 seconds, and it has 2 each top & bottom. I'm still experimenting to find exact settings, but in Air Fryer mode it crisps up/rebrowns 3 slices of pizza in ~3 minutes just perfectly; that's less than half the time it takes in the oven. Overall, the general feel of the thing is "very nice toaster oven". I'm totes down widdat.



Logitech K850 Bluetooth KB & mouse; totes a no-brainer for $12. IIRC, this model is supposed to washable under running water. 




Acer ES1-512-C1PW laptop; also a no-brainer  for $30. N2840 CPU/4GB RAM/500GB HDD; only visible fault is locked account and 2 missing keys. Even booted from battery. Depending on cost of RAM/SSD, may just be a quick flip arbitrage purchase. 




Intuos CTL-4100 Drawing pad. Still supported on both Mac & PC. Looks like it may need a new nib; I may still have some from my old HP PADD which also used a Wacom stylus.


   

And finally... What's better than Mandingo Fan 200 for 6 dollars...? 2 more for $8 each. Sadly, this was not a half-price day.   

No, I still have no idea what I'm going to do with them. I think I may have a fan fetish... 


mnem

[vk6zgo]

(2) Clothes drying on a backyard line is not possible in a high rise (unless you live in Hong Kong), so each flat will be using energy hungry electric clothes driers.In the Summer, these will heat up the flats, with a necessary increase in the use of airconditioners, to further increase energy consumption, on the washing days.

OK, in Countries with no discernible Summer, & very few rain free days, outside drying may not be an option, but certainly in Australia, & many others, it is---& it is free!

Most moderately priced apartments (flats) here do not have individual hook ups for washers/dryers. A central laundry room is the norm although some have none so you must visit a laundromat. We have a laundry room here but only one washer and dryer. Combine that with inconsiderate individuals who don't promptly remove their laundry makes it sometimes a PITA.

I do most of my cooking with a toaster oven or microwave so I rarely use the stove/oven. Especially in Summer.   

It seems to be the trend in Oz to make space for washers & dryers in the new flats ----the developers here use "apartments" as a sort of indication of being "upmarket"---go figure.
Combined with that, is the lack of communal Laundry rooms in the newer ones.
 
In any case, the energy use would be similar, except for the additional aircond use, although the big industrial dryers are more energy efficient.

[vk6zgo]

IN OTHER NEWS: Thrift Haul No 227:






   

And finally... What's better than Mandingo Fan 200 for 6 dollars...? 2 more for $8 each. Sadly, this was not a half-price day.   

No, I still have no idea what I'm going to do with them. I think I may have a fan fetish... 


mnem

You could always put the pic on OnlyFans!

[cyclin_al]

You could always put the pic on OnlyFans!

  ... 

[mnementh]

*takes a quick look-see*

Ummm... I think I'm gonna stay over here on /r/dragonsfuckingcars... much safer. 

mnem
*currently nuking a Acer*

[mnementh]

Yeah, that's a large part of what I wind up getting into painful recursive debates with some folks (mostly those who are even worse at math than I am... how is that possible?  ); they just can't seem to grasp the fact that every step you get away from the point the energy is created to the point work is done is an order of magnitude of loss in total system efficiency.

What's really disheartening is trying to explain to these people that this model goes all the way up to the root source of all energy on this planet, which is the sun itself. Every step we get away from using that energy directly is another step of storage in some form... and again, an order of magnitude of loss in overall efficiency. 


mnem

This is why I wonder about people who want to use electricity generated from a home solar electricity system to provide power for a HWS, when, with little effect upon the roof area available for the solar panels, they can have a solar HWS, with the solar energy directly heating the water.

Another thing is pushing high density living on the basis of energy saving by making it "closer to where people work", thus, allegedly saving energy used for transport.
 
Two things seem obvious to me:-
(1) Not everybody works in the City Centre, so they will need to travel across the City to their work.
(2) Clothes drying on a backyard line is not possible in a high rise (unless you live in Hong Kong), so each flat will be using energy hungry electric clothes driers.In the Summer, these will heat up the flats, with a necessary increase in the use of airconditioners, to further increase energy consumption, on the washing days.

OK, in Countries with no discernible Summer, & very few rain free days, outside drying may not be an option, but certainly in Australia, & many others, it is---& it is free!

Ummm... as someone who grew up with clothes dried on a line and knows the misery of road-rash on my junk and nipples rubbed raw from crunchy shirts and jeans that know how to "plank"...

Aww, hey-ell NO. You can have my tumble-dryer when you pry it from my cold, lifeless claws.

mnem
Or after Stuart over there is done fucking it...