Test Equipment Anonymous (TEA) group therapy thread

[Vince]

5) Cats and humans : doesn't your lab have a door that can close ?! 

I guess I'm stating the obvious by supposing you've never had a cat. So, insert your anti-cat rant here:

I love cats and have had cats for the first 20 years of my life in my parents house, and no doors anywhere to keep them from getting in the garage or lab.
They all survived just fine. I guess they were more clever than your average cat ?! 

Again if you are worried about  your cats just close the fucking door and on the outer side fit a handle whose shape is unlikely to be opened by the cat, should you have one that's of the more clever and capable type, that likes to jump on door handles.

It's not rocket science really 

[capt bullshot]

Again if you are worried about  your cats just close the fucking door and on the outer side fit a handle whose shape is unlikely to be opened by the cat, should you have one that's of the more clever and capable type, that likes to jump on door handles.

In my parents house, there are some door handles rotated by 90° (upright instead of horizontal) - guess why
It's really interesting to watch them learning and opening the doors.

[mnementh]

It's fixed. Dismantling and re-swaging the retainer pegs on the "display module" wasn't too bad, but it did turn into a wee bit of a bodge as I had to steal a 0603 LED from the ALARM location, however I only had a few red ones in all my crap for a replacement ATM.

It just screams "WRONG!!!" out loud at me... tho I'm certain by morning I'll have forgotten all aboot it, since I have my favorite clock back. 

Good job, the evironment will thank you for saving one more consumer item from being prematurely dumped! I like this spirit.
Yes, there's one "WRONG!!!" with it, it's got a blue display. Such thing would never make it's way into my ambience. Especially for an alarm clock to be used in the bed room, nothing but a gently glowing red LED display is acceptable.

Yeah... that's actually why I prefer it. Red LED displays are just a fuzzy blob at 2m to me without my glasses; even larger ones than this. This one I can actually read.

I assume it's to do with the whole rods vs cones vs light wavelength thing; doesn't matter. Blue LEDs are the clearest to me. OTOH, I've long had issues with seeing in low light... or even "normal" light.

My EDC flashlight fetish is more than just that; it really has been a necessity to function as a "fixer" and in much of my day-to-day life since my 30s.

mnem
*blind as a baseball bat*

[Robert763]

That is unusual.
Most people have trouble focusing on blue light sources due to fluorescence in the structures of the eye.

[mnementh]

For something that is actually interesting, a RM564.   Is this something reasonable for someone (me) who has not worked on one of these before?   I like the idea that it is rack mountable...  might be worth a low-ball offer.
Biggest problem is that it is far away, closer to where the dwagon lives used to live.   

Here !  I was in your position 4 years ago when I embarked into the restoration of my first tube anything, a Tek 317 scope.

Here is my take on it.

1) Don't know about the Canadian market, but here a rack mount Tek scope of any model and vintage is very rare. So if really you want a rack mount Tek scope, the obvious is to get it before someone else does, especially since the price is fair as it is. If you get to start work on it in a year or two only, and have by some miracle found another rack-mount scope that you like better, you can always sell the firsts one if you want to, but more likely you will keep it as a part mule to help you fix the "new" one. Being able to to quickly swap tubes is priceless. Saves you from buying new tubes you might not even need, and waste time waiting for them being delivered.

2) As was said, if really you feel overwhelmed by that (apparent only) complexity of a Tek tube scope, yeah why not get some simpler piece of tube equipment. 

3) 564 is all tubes no trannies, well according to Tekwiki at least. 564B is 100% PCB and transistors, well  I mean the chassis itself only. The plug-ins of course are whatever you decide to use, so will probably be tube based.

4) Look at pics of the 564 on Tekwiki : once you remove the plugins, the circuitry of the main frame is readily accessible on both side, just pop the top and bottom covers and your right there probing around.

5) Cats and humans : doesn't your lab have a door that can close ?!  If you are in the lab, well of course you are there to tell people to be careful, but I guess by now they must already know they should not approach or touch stuff plugged in on the bench anyway ?!
Then when you are NOT in the lab hence can't see what others are doing... well I will state the obvious and say that you should not leave an old tube scope unattended for too long... just in case !     If you need/want to anyway, well just close the door. IF it does not have a key... put a huge red sign on the door to INSTRUCT people not to enter because of dangerous high-voltages on the bench.

6) Learning tubes. I don't know how little you know. You probably know more than I did. I am not that old so never learned anything about tubes at school. Didn't even know they existed. So to me they couldn't possibly be more mysterious... I had no idea what principles governed their operation, had n idea what all the pins did, had n idea what all the weird looking symbols meant on the schematics. It was black magic to me, pure and simple. Alien.

So I too was scared and reluctant at first, fearing for my safety and feeling I would be too incompetent to fix it.  But you know what ? It's all BS ! As Mansaxel said, tubes are very simple ! Of course you can come across the odd one with a weird failure mode... but you get to know the various failure modes, just like any device, no big deal. Plus in practice most of them aren't defective.. they are just "tired", low gain, that's all.
It's not like solid-state was any better ! They too can have their weird failure modes too ! An intermittent bond inside an IC package isn't exactly the most obvious and  fun thing to debug for a new comer I would think !
Plus, you don't even need to be an expert in all faluure modes (certainly I am NOT !  ) to be able to tell if a tube is bad !
In practice what you do is work on a particular section of the circuit, say stage 3 of the vertical amplifier or whatever... you see the signal coming in is good, coming out isn't good any more, so you know something is going on there. Can be either the tube or the discrete components around it. So you just check supply voltages, then look for visual clues of a damaged discrete component, then measure them quickly with your DMM.. if all is well then just swap the tube as see if that fixes it ! Job done. Next.

The good thing with old Tube Tek scopes is they all have a very comprehensive service manual. Block diagram, and a lengthy description of how each and every section of the scope works. The on the schematics, you have test points showing DC voltages as well as waveform.

So you just go through that calmly, methodically... and you will fix that scope I am sure ! Plus of course, you are not alone ! You can post on here, and of course subscribe to the "Tekscope" mailing list, where all the tube Tek grey beards/experts reside ! They have alwyas been very friendly and helpful to me ! 

To make sense of the schematics : it's easy, no really ! Just consider the tube as FET transistor...3 pins. The "grid" is like the gate, "anode" is like the drain, and the "source" is like the cathode. That's all. You give the anode some juice, 200 or 300 or 500 volts, apply some voltage at the grid and you will get more or less current flowing between the anode and cathode. That's it basically !  Don't care about all the other pins  ! You have two pins for the filament/heater... all you need to know is that it's powered on all the time and is required for the tube to work.  It's merely an accessory. You need it, you know it's there, but it's not required to understand/read the schematics. So much so that as you will see, the filaments are not even represented in the schematics ! You only see them appearing once, all grouped together, in the power supply schematic.. of course, because you need to power these filaments. But in all other schematics, every time you se a tube symbol, you will NOT see the filament. It's just not required to the understanding of the circuit.
What you might see in schematics is EXTRA pins here and there.... A "Triode" as its name suggests, as only 3 active pins : the 3 pins analogous of the FET transistor discussed above. It's the bare minimum you need for the thing to work. but you can also have a "Pentode" tube.. again as the name suggests, it has 5 pins not 3. However, these two extra pins... you don't even need to care about 99,999999% of the time. The designers had to care... but for repair purpose, just ignore them plain and simple. Usually tehy are just tied to fixed potential via a high impedance resistor divider, and often times, these extra pins are simply tied directly to one of the other power supplies, or to the cathode....  really you can just ignore them. Just look at the grid/anode/cathode, that's, the "transistor".. it's all that you need to understand how things work.  Sometimes, one of these two extra pins will NOT even be accessible ! It will already have been, internally, connected to the cathode or whatever.

Once you have all that in mind... you can read the schematic easily. Every time you see a tube you just see a FET transistor, and then suddenly it all seems simple and clear as water !    .... and you will realize that all the common transistor circuits you learned at school, astable/multivibrator, flip-flop, amplifiers, voltage regulators etc... were not transistors inventions... they were already all designed and working with tubes, and only adapted later to make use of trannies.. just adapted, not invented, not new stuff... there is no black magic at all in tube circuits !


So... I say, grab this rack mount scope while you can because god knows how long it might be before you can find another one especially at a fair price like this.  Then you have all the time in the world to see how you want to proceed about it...
Pop the covers, see for yourself how it's put together. Read the manual, identify where each section is.. familiarize yourself with the scope...
If you still don't feel like going straight at it, yeah as was suggested, why not grab whatever cheap piece of junk TE that's got tubes in it but is simpler in design, less tubes.. and get some hand-on experience on it.. then start probing around your Tek scope progressively, a step at a time !

Have fun, I sure do !!!   

That is actually a very good outline of the most fundamental pitfalls you'll be up against; no point in rehashing it.

Two other things aboot choob circuits; one is that they are generally more tolerant than transistors of excessive loading in terms of whether they'll blow up or be damaged immediately, but really low impedance loads are usually driven with some form of matching transformer or or other circuit to drop the load presented to the tube.

Those operating voltages are the reason, of course; old man Basche taught me to think of the difference in general as "a transistor is a current amplifier; a tube is a voltage amplifier".

mnem
 

[mnementh]

That is unusual.  Most people have trouble focusing on blue light sources due to fluorescence in the structures of the eye.

 

Warm white LED lighting in the 3000K range makes everything look fuzzier to me too; but in my living room I prefer the softer lighting. In my workspaces (lab/bench/kitchen) I always preferred fluorescent and now "daylight white" LEDs in the 5000K-ish range.

It just makes everything seem crisper to me.

mnem
"Aziz, LIGHT!!!"

[Neper]

I love cats and have had cats for the first 20 years of my life in my parents house, and no doors anywhere to keep them from getting in the garage or lab.
They all survived just fine. I guess they were more clever than your average cat ?! 

Same here, just not the first 20 but the last 40 years. There's just one thing they all hated: closed doors and they make it very clear that they do.

So, from many years of experience, I found it a bit strange that someone would suggest closing doors. I wouldn't want to do some critical repair to the sound of our cats working their way through the door blade. 

[mnementh]

5) Cats and humans : doesn't your lab have a door that can close ?! 

I guess I'm stating the obvious by supposing you've never had a cat. So, insert your anti-cat rant here:

I love cats and have had cats for the first 20 years of my life in my parents house, and no doors anywhere to keep them from getting in the garage or lab.
They all survived just fine. I guess they were more clever than your average cat ?! 

Again if you are worried about your cats just close the fucking door and on the outer side fit a handle whose shape is unlikely to be opened by the cat, should you have one that's of the more clever and capable type, that likes to jump on door handles.

It's not rocket science really 

mnem
*toddles off to nuke a 3DP*

[Zucca]

And now for something completely different:

https://www.eevblog.com/forum/repair/yokogawa-ta520-time-interval-analyzer/

So interesting.... Thanks for sharing.... you should start a youtube channel.

[duckduck]

I have once again swooped in like a dark spirit to collect the ashes of someone's dreams.

I finally snagged the mighty Fluke 87V. I found it on Craigslist for USD180. It came with an assed-out set of Fluke probes. I opened it up and it looks good inside. Bonus: the previous owners had left the screen protector on, which I was the first to remove. The screen plastic is in as-new condition. Unfortunately, the first owner carved his initials in the front case and also wrote his initials in magic marker on the top of the rubber baby buggy bumper. I'm hopeful that that will mostly come off with some elbow grease. The RBBB is in otherwise excellent condition and the integrated folding stand works perfectly.

The guy I bought it from was an 8-color printing press operator for 33 years who lost his job. He signed up for a state job-training program to become an electrician and bought a used meter off of "JSS", the possessive sparky. Once printing-press guy found out that the job placement rate for the program was 33%, he decided to pursue other options and liquidated his meter for some quick cash.

I swapped out the alkaline 9V battery for a NiMH. The 87V now joins my 26III and my 179.

[Zucca]

the first owner carved his initials in the front case

People who write on TE plastic with something sharp should be sent to Tehran to get their hands cut off.

That said nice score! The 87V is a must!

[cyclin_al]

and no doors anywhere to keep them from getting in the garage or lab.

You must have had cats that were bored and sleeping all the time.

The one thing that cats are truly obsessed with is getting to the side of the door that is off-limits.  I really mean truly obsessed!
They will go to great ends to outsmart and get past the humans.

Close door.
Remove cat 1.
Search for cat 2 who snuck in while evicting cat 1.
Remove cat 2.
Search for cat x who snuck in while evicting cat y.

[wolfy007]

HAHAHA, I finally have one of these Tektronix cobolt blue mugs, scored one last week and now in my hands. 

Oh and also picked up an Agilent SA (on gumtree of all places) and a HP cup also.

[med6753]

and no doors anywhere to keep them from getting in the garage or lab.

You must have had cats that were bored and sleeping all the time.

The one thing that cats are truly obsessed with is getting to the side of the door that is off-limits.  I really mean truly obsessed!
They will go to great ends to outsmart and get past the humans.

Close door.
Remove cat 1.
Search for cat 2 who snuck in while evicting cat 1.
Remove cat 2.
Search for cat x who snuck in while evicting cat y.

Just ask Cubdriver. He has multiple cats and they "help out" in his lab all the time. 

[med6753]

HAHAHA, I finally have one of these Tektronix cobolt blue mugs, scored one last week and now in my hands. 

Oh and also picked up an Agilent SA (on gumtree of all places) and a HP cup also.

My 547 cup is still in black hole hell. 

[cyclin_al]

5) Cats and humans : doesn't your lab have a door that can close ?! 

I guess I'm stating the obvious by supposing you've never had a cat. So, insert your anti-cat rant here:

I love cats and have had cats for the first 20 years of my life in my parents house, and no doors anywhere to keep them from getting in the garage or lab.
They all survived just fine. I guess they were more clever than your average cat ?! 

Again if you are worried about your cats just close the fucking door and on the outer side fit a handle whose shape is unlikely to be opened by the cat, should you have one that's of the more clever and capable type, that likes to jump on door handles.

It's not rocket science really 

mnem
*toddles off to nuke a 3DP*

The Fujitsu keyboard in the photo is a rebranded Logitech KS-2500.  It must be 30 years old now; great keyboard & using it to type this.
The orange & white cat is now overweight at 19 lbs.
The rest of the image is not accurate...

[cyclin_al]

and no doors anywhere to keep them from getting in the garage or lab.

You must have had cats that were bored and sleeping all the time.

The one thing that cats are truly obsessed with is getting to the side of the door that is off-limits.  I really mean truly obsessed!
They will go to great ends to outsmart and get past the humans.

Close door.
Remove cat 1.
Search for cat 2 who snuck in while evicting cat 1.
Remove cat 2.
Search for cat x who snuck in while evicting cat y.

Just ask Cubdriver. He has multiple cats and they "help out" in his lab all the time. 

They do.  I had one of mine jump up in front of the camera while on a video-conference with a very high-ranking civil aviation official! 

[PA0PBZ]

Oh and also picked up an Agilent SA (on gumtree of all places) and a HP cup also.

I have a key generator for the options and since it's out of support not afraid to use it
PM me the ID and what options you want.

[Cerebus]

Yeah... that's actually why I prefer it. Red LED displays are just a fuzzy blob at 2m to me without my glasses; even larger ones than this. This one I can actually read.

I assume it's to do with the whole rods vs cones vs light wavelength thing; doesn't matter. Blue LEDs are the clearest to me. OTOH, I've long had issues with seeing in low light... or even "normal" light.

That is unusual.
Most people have trouble focusing on blue light sources due to fluorescence in the structures of the eye.

Anybody who has been to an optician and has been refracted (as the opticians call it) will be familiar with being asked to look at identical black figures side by side, one on a red background, one on a green = "Which is clearer? Red or green?". Know as a duochrome in the trade. One something this (there are lots of variants):



The reason that they do this is to ensure that they get things properly in focus for us at wavelengths roughly halfway between those two colours. The green will focus slightly in front of the retina, the red slightly behind, and yellow, if it was there, would fall smack on the retina. Like this:



The quantitative difference in focus for red and green is about 0.5 dioptres.

The eye has surprisingly high dispersion depending on wavelength, our eyes have pretty bad chromatic aberration. We don't normally perceive it because of all the post-processing our brains do - it will take information from all colours and just fill in the gaps. The eye naturally focuses in the yellow and that is why black on yellow looks crispest to us - a good reason why all those serious warning signs are in black and yellow.

Looking at the focus diagram above again it's pretty clear that the focus for blue falls even further in front of the retina. In effect everybody is shortsighted in blue. If all you've got to work with is blue light you are going to both have and perceive a fuzzy image because there isn't enough information for your brain to fill in the gaps.

If Mnem is longsighted that would be an explanation why he can see blue better than red without his glasses. If he isn't but is shortsighted then the fact that he perceives blue better than red without his glasses is just more proof of what we've all known all along - that he is weird.

[Cerebus]

the first owner carved his initials in the front case

People who write on TE plastic with something sharp should be sent to Tehran to get their hands cut off.

That said nice score! The 87V is a must!

The punishment I invented for electronics abuse the other day was "should have their toes desoldered".

[Vince]

and no doors anywhere to keep them from getting in the garage or lab.

You must have had cats that were bored and sleeping all the time.

Boy I thought the main subject was your first tube scope, I must have been wrong !

Well cats are like huna beings, they share some common traits yet are all different.
Cerebrus will sure give me the correct number, but IIRC cats and related mammals spend like 80% of their time sleeping anyway... remaining 20% for eating fighting and fucking.
 
The way I remember all the cats we had, is that although they sure wanted to get behind doors, they didn't want it badly enough to jump on handle, or so rarely. They might give it a quick try and then give up rapidly. They would just meow for a long time till we came to open the door they wanted open. Most of the time would say OK  you can get upstairs, go there.. as long as you don't pee please !
Then tehy would just find a spot to sleep, would come back doxwnstairs looking well rested and ask for food...

So no I don't remember them as being obsessed about opening doors to the point of trying all day long to improve their techniques, nor do I remember any of them going through the trouble of getting a toolbox and circular saw from the garage either...

They were mostly likeable I would say ! 

Also, they were cats, animals, so they spent most of their time outside living their cats life, and they would be given food usually outside on the terrace.

They were not lazy cats spending all day long inside, not at all. They would come inside only to say hi and ask for some food, that's about it.

[BU508A]

HAHAHA, I finally have one of these Tektronix cobolt blue mugs, scored one last week and now in my hands. 

Oh and also picked up an Agilent SA (on gumtree of all places) and a HP cup also.

My 547 cup is still in black hole hell. 

 

What a shit show. How hard can it be to deliver a small parcel, containing one mug? 

I hope, you'll get it soon.

[Neper]

So no I don't remember them as being obsessed about opening doors to the point of trying all day long to improve their techniques, nor do I remember any of them going through the trouble of getting a toolbox and circular saw from the garage either...

Why should they? They have claws. And while they won't succeed in getting through the doorblade, they can use them to make enough of a racket to get what (or rather where) they want.

Especially when they know there's some warm and cozy hollow-state electronics on the other side.

[wolfy007]

Oh and also picked up an Agilent SA (on gumtree of all places) and a HP cup also.

I have a key generator for the options and since it's out of support not afraid to use it
PM me the ID and what options you want.

Thanks, but I think all the options are already installed;
506-Frequancy Range 100K-6GHz
P06-Preamplifier 6GHz
TG6-Tracking Generator 6GHz
N8995a-SR6- Stimulus Response Measurement
271-Spectrogram
AFM-AM/FM Tune&Listen
N8996a-1FP-AM/FM Modulation Analyser

Not aware of any other options.

[wolfy007]

HAHAHA, I finally have one of these Tektronix cobolt blue mugs, scored one last week and now in my hands. 

Oh and also picked up an Agilent SA (on gumtree of all places) and a HP cup also.

My 547 cup is still in black hole hell. 

Hope it comes through, those are cool mugs!