Test Equipment Anonymous (TEA) group therapy thread

[med6753]

If anyone wants to offer my very sore throat, a good home, it's yours FOC, it's driving me Fecking crazy, it is the third day that I've had it, but hopefully, as it got so bad today, that might mean it will better tomorrow? Things do generally get worse as they begin the healing process. No other symptoms except a slight cough and to night I feel so cold. I don't have a fever, headache or any muscular aches and pains, just this stabbing pain every time I swallow, bastard thing 

Go get a CV test. While out get some medicines plus stuff Grandma would use...honey, lemons etc.
GWS.

Seconded.

While you are at it, add paracetamol and whisky/vodka/etc. Sometimes stupefaction is the best course of action.

Yeah, I had myself a lovely steaming hot mug of coffee, plenty of sugar and well laced with whiskey last night before going to bed, and I'll do the same tonight. Can't risk doing that during the day in case I have to dash out shopping because SWMBO needs something I forgot, to make dinner etc, I never drink and drive, and as I'm the only person who can drive, then that's my job.

Coffee before bed is counter-intuitive!

When feeling grotty I do my utmost not to go out - for my sake and for others' sake.

For covid, the best description of masks' effectiveness appears to be

And don't grab any soggy ropes. 

[tautech]

And don't grab any soggy ropes. 

Or eat yellow snow ! 

[mnementh]

   ...not a total win yet.

One thing I've seen out in the wild is manufacturers using the THERMISTOR circuit as more than a thermistor; they will often use it to communicate information aboot the battery back to the host device, either via simple voltage level monitoring or digital information they will tell the host battery type, capacity, Ser#, temp, even number of charge/discharge cycles and more.

So still more real life testing to go... If the unit thinks this is the wrong type of battery (NiMH instead of Li-Ion) it may set a wrong low-voltage threshold, or even try to charge it via peak-detection rather than CC/CV as a Li-xx pack needs. I'm not worried aboot it damaging anything with the BMS module acting as traffic cop; but it may not charge automatically like it should (this thing is supposed to find its dock and auto-park itself to charge); it may stop too soon or take days or just not start a proper charge cycle at all.

But at least I've confirmed pretty well that the cells in the pack are still good. I think.

If it doesn't work, I've had fun tinkering; then the choice will be whether to buy the bespoke Roomba Chinesium BMS, or just get a cheap NiMH pack off Amazon.

So... now that I finally have the thing charging again... 

It looks like I'm back at this hurdle again. When charging a NiMH pack, the Roomba does the old-school "peak detect via waste heat" method, monitoring a PTC thermistor attached to a cell in the middle of the pack. Obviously this is not a good method for charging Li-xx packs. So, I monitored battery voltage vs thermistor as the Li-Ion pack approached charge terminus; the thermistor in the pack changed only a few thousand ohms before the BMS killed charge and battery voltage at the connector (not internal pack voltage) jumped up to ~22V, which is the unladen output of the charger base, but thermistor slope is NTC. 

This means 2 things...

1) The built-in secondary runaway protection of monitoring the pack temp is defeated. The charger continues to pump voltage into the pack until the BMS interrupts the circuit on OVP at ~4.25V/cell. Not ideal; OVP is supposed to be secondary level failsafe protection, not primary charge control.

2) When OVP interrupts charge to the cells, the Roomba does not see this as a completed charge cycle, but rather continues to try and charge the pack, until the watchdog notices an extended period idling at ~22V, then it throws that damned ERROR 5 again.

TL/DR: My suspicion is that the OEM BMS probably monitors the battery cell voltages as any Li-xx BMS would, then synthesizes a sample voltage out to the thermistor sense pads which mimics the behavior of the NiMH PTC thermistor, ultimately coinciding the optimal 4.2V/cell terminal voltage with a sample output to the thermistor pads which is the same as the Roomba would normally terminate a NiMH charge cycle.

Then the Roomba knows the battery is ready for it to go to work, and end-user experience with either NiMH or upgrade extra-$$$ Li-Ion pack is completely transparent and drop-in simple.

At this point, I can use the Model 805 Roomba completely normally with the NiMH pack from my older 500-series unit.  I can also charge the Li-Ion pack manually using my Reaktor and swap it in if I feel like it; turns out the Roomba's LV cutoff works out to ~3.1V/cell under load, which is actually halfway decent. I'm feeling pretty sanguine aboot spending the $15 on the Chinesium Roomba BMS now, just that the wait is gonna suck...

But now I have to turn this       and this      into a working Roomba again.   

mnem
lets hope dr dwagon can close the patient up without leaving his watch inside...   

[tautech]

Pound for pound this Roomba has given you more mileage than even Med's Tek 212. 

[med6753]

Pound for pound this Roomba has given you more mileage than even Med's Tek 212. 

But he still has a long way to go to top the mileage on the Type 547, including several bouts of magic smoke. 

[xrunner]

This is kind of TEA-ish if you want to get the right screw (or nut) to fix that TEA you are working on out of your screw stash. If you have a mixed-up box-o-screws you saved over the years it's a hassle to find what you want. Well a mixed-up box is what I have and I'm going to sort them all out with the help of this come hell or high water, so I don't have to fuss with finding what I need any more. I have had a cheap plastic screw gauge but this is much nicer.

Zinc Plated for Inch Size -

Includes 14 Inch Size part numbers: 6-32, 8-32, 10-24, 10-32, 1/4-20, 1/4-28, 5/16-18, 5/16-24, 3/8-16, 3/8-24, 7/16-14, 7/16-20, 1/2-13, 1/2-20

Black Oxide for Metric Size -

Includes 12 Metric Sizes part numbers: M4x0.7, M5x0.8, M6x1.0, M7x1.0, M8x1.0, M8x1.25, M10x1.0, M10x1.25, M10x1.5, M12x1.25, M12x1.5, M12x1.75

Thread sizes are permanently stamped onto each gauge. The individual gauges rotate freely on the wire cable for fast thread verification.

[Neomys Sapiens]

If anyone wants to offer my very sore throat, a good home, it's yours FOC, it's driving me Fecking crazy, it is the third day that I've had it, but hopefully, as it got so bad today, that might mean it will better tomorrow? Things do generally get worse as they begin the healing process. No other symptoms except a slight cough and to night I feel so cold. I don't have a fever, headache or any muscular aches and pains, just this stabbing pain every time I swallow, bastard thing 

Go get a CV test. While out get some medicines plus stuff Grandma would use...honey, lemons etc.
GWS.

Seconded.

While you are at it, add paracetamol and whisky/vodka/etc. Sometimes stupefaction is the best course of action.

Even better:
1/3 of a strong spirit (for expl. cask strength whisky)
1/3 Manukka Honey (UMF15+)
1/3 finely shredded (or powdered) ginger
mix thoroughly
take 1tsp every several hours if sick, otherwise 1tsp/day

[med6753]

And here is what I collected this afternoon, a little Tek scope, the journey down wasn't much fun, very slow on the M6 in Birmingham and completely stationary for about 15 minutes, while a stranded vehicle was removed (apparently).    I thought I would give it a quick test this evening, amazingly it seems to work, needs the two broken controls fixing and the trigger isn't working as good as I think it should be.   Anyone know why these curves show on the CRT, could it be related to the brightness?? Can't turn it down as the control is broken off.      Teardown will have to wait for another day.

David

I have a newer Type 321A. It does not have those curve marks on the CRT. But I suspect they would go away if you could turn down the brightness. The Trigger works best in "Auto". If it doesn't lock correctly adjust the Stability trimmer. The scope is loaded with germanium 2N2207 which are very prone to developing tin whisker shorts.

Can't say I've ever seen marks like that on a working CRT, need to find some small 1MΩ & 2MΩ HV pots, or try & fix the existing ones for the brightness problem.   The trigger was in "auto", it only seems to want to trigger on certain frequencies, adjusting the oscillator frequency a small amount causes it to lose lock.

The 321 manual on Tek wiki mentions the OC170 used in the vertical & timebase circuits, both areas that are functioning, maybe some have already been replaced.
And I already knew about the tin whiskers in old Mullard/Philips AF11x (& other series) transistors, many of my old radios are infested with the unreliable things.
Here is an old thread on the UKVRR forum about them : https://www.vintage-radio.net/forum/showthread.php?t=5058
And some faulty NOS AF114 transistors got sent to NASA: https://nepp.nasa.gov/whisker/anecdote/af114-transistor/index.html

David

I hate to be "that guy", but after seeing that pic so many times, I gotta say it out loud: My gut tells me it's a damaged CRT. 

mnem
I do hope I'm wrong.

I've seen damaged CRTs before and the trace is usually messed up too, example below from here; https://www.vintage-radio.net/forum/showthread.php?t=106959


Oddly it wasn't seen in the sellers picture, so if it is damaged it must have happened on the journey home.

David

Hold off on drawing any conclusions until after you can get the intensity turned down. I'm still of the opinion it will clear up.

I got my Type 321A off the shelf to compare. No signal input. Set the trigger to normal (no sweep). Turned intensity up to maximum. Under ambient light could barely see what shows very clearly in the dark. It's not exactly the same as you are seeing nor anywhere near as bright. My first thought was the bias on yours set too high but there is no bias adjustment. But I still think you should fix the focus and intensity pots first and then check and see what you have.

 

[duckduck]

New acquisition:

Analogic / Data Precision 8200
6 1/2 digit voltage and current calibrator

It does have the IEEE-488 option. It does not have the 1000V option. If the selector is rotated to the 1000V position, "Err0r" is displayed. It is in excellent condition. It appears to be completely original and unmolested. Some of the rotary encoders "skip" every now and then. I saw a post from a guy that said he disassembled and cleaned the encoders on his 8200s. That gives me hope that such a thing is possible. The PCB was designed in 1980. There is a manual with parts list and schematics available for download. ICs inside the unit have date codes from 1992 and 1993. It is the third 19" rack-mountable piece of TE I own (HP 3455A voltmeter, Keithley 236 SMU). Too soon start planning for a small rack?

There is a "REJECT" sticker on the front of it, and on top, the reason for rejection (see attached pictures). Uh, oh. Looks like someone didn't read the owner's manual (highlighing is mine).

The DP8200 and my Instek DMM were both warmed up. Which one is right? Is either one right? Pity the man with two uncalibrated clocks. The solution is common knowledge around here: buy more uncalibrated test equipment!   

EDIT:

https://www.download-service-manuals.com/download.php?filename=Data_Precision--8200--service_and_user--ID8214.pdf

EDIT EDIT:

I just jammed it in a open hole in my shelf for the picture. I'll have to find a more permanent place for it.

EDIT EDIT EDIT:

My 2^8th post!

[srb1954]

Here is a rather unusual Tektronix piece of gear ?! 

https://www.leboncoin.fr/voitures/2061899528.htm

Any idea ? A special edition of some sort perhaps ?!

Definitely not Tektronix. It is the wrong shade of blue.

[srb1954]

Progress with the first 5245L: Replaced all neon bulbs. What a mess. All copper wires were corroded, most have them already were destroyed at one leg.

Where did you source the neons with the nice long leads?

I have the same problem of corroded neon leads with my 5245L but I haven't been able to find neons with sufficiently long leads to repair the decimal point assembly and still allow manipulation of this assembly when gaining access to other parts of the unit.

[srb1954]

"My job is so secret, even I don't know what I'm doing."
(seen on a t-shirt)

For a lot of people they could strike through the first 6 words on this t-shirt and the message would still be applicable!

[Zucca]

New acquisition:

Analogic / Data Precision 8200
6 1/2 digit voltage and current calibrator

droolling nice one!

[Zucca]

He is nuts. And willing to spend upwards of $20K to get them shipped to him. Wish I could throw $20K away and not even think about it. 

I'm wondering what the underlying reason is for this project. Is it a library for posterity? Is it for some business reason? Does anyone know why he wants to go through this painful exercise?

one minute of silence for TerraHertz, his TEA virus presents some interesting mutations.

[mnementh]

Ph'nglui mglw'nafh Cthulhu R'lyeh wgah'nagl fhtagn.

mnem
"In his house at R'lyeh dead Cthulhu waits dreaming."

[mnementh]

Ancestors help you med, that's the Eye of Sauron. You'd better put your Palantir away, before his gaze falls upon you. 

mnem
not quite as creepy as CthulhuBot, but a damned good try.

[KG7AMV]

I swear no more test equipment till 2022..

 

[Zucca]

I swear no more test equipment till 2022..

[mnementh]

Pound for pound this Roomba has given you more mileage than even Med's Tek 212. 

But he still has a long way to go to top the mileage on the Type 547, including several bouts of magic smoke. 

LOL... yes, only one magic smoke so far on this project. 



I bow before thee, Oh Master of the Mystic Smoke...

mnem
* toddles off to ded*

[mnementh]

This is kind of TEA-ish if you want to get the right screw (or nut) to fix that TEA you are working on out of your screw stash. If you have a mixed-up box-o-screws you saved over the years it's a hassle to find what you want. Well a mixed-up box is what I have and I'm going to sort them all out with the help of this come hell or high water, so I don't have to fuss with finding what I need any more. I have had a cheap plastic screw gauge but this is much nicer.

Zinc Plated for Inch Size -

Includes 14 Inch Size part numbers: 6-32, 8-32, 10-24, 10-32, 1/4-20, 1/4-28, 5/16-18, 5/16-24, 3/8-16, 3/8-24, 7/16-14, 7/16-20, 1/2-13, 1/2-20

Black Oxide for Metric Size -

Includes 12 Metric Sizes part numbers: M4x0.7, M5x0.8, M6x1.0, M7x1.0, M8x1.0, M8x1.25, M10x1.0, M10x1.25, M10x1.5, M12x1.25, M12x1.5, M12x1.75

Thread sizes are permanently stamped onto each gauge. The individual gauges rotate freely on the wire cable for fast thread verification.

Yeah, I recommended these to Vince a while back when he was having shit-fit conniptions over all the American fractional/decimal machine screws on his HP gear. You can get them all over AliEx for $20-25 a set. A bargain, IMO.

mnem
*knocks self unconscious with a tap & die mallet*

[med6753]

I swear no more test equipment till 2022..

 

1. You're a terrible liar.

2. You need to build a decent bench.

 

Edit.....here's some inspiration. The price of lumber is coming back down. Get busy. 

[bitseeker]

A memory aide (for anyone who'll find it useful) for differentiating the "it's"/"its" forms is that "its" is possessive, like "his" and "hers", all of which do not have an apostrophe. Granted, one could misremember the female possessive pronoun as "her's", but surely the male possessive pronoun "hi's" does not look right.

An even better memory aid is having an English teacher who for a whole term made the class stand up when he entered the room (as was normal when any teacher entered the room) and instead of the usual "Good morning class.", "Good morning Sir." ritual made us chant in unison "It's with an apostrophe means IT IS!". To this day, fifty odd years later, if I ever have a moment of doubt about how I should punctuate "its" I can hear a whole class chanting in my mind's ear.

While we're being 'correct' about apostrophes I might point out that an aide is a person who assists whereas a memory technique is spelled aid without the 'e'. You can probably blame the borrowed French "aide-mémoire" for your slip. I would were I you. 

Yep, "aide" was a typo and an ironic one at that. Earlier that day I was going to explain the difference between "aide" and "aid" to someone else. Freudian slip, perhaps. Thanks for the correction.

[AVGresponding]

Progress with the first 5245L: Replaced all neon bulbs. What a mess. All copper wires were corroded, most have them already were destroyed at one leg.

Where did you source the neons with the nice long leads?

I have the same problem of corroded neon leads with my 5245L but I haven't been able to find neons with sufficiently long leads to repair the decimal point assembly and still allow manipulation of this assembly when gaining access to other parts of the unit.

Couldn't you just solder on some extensions?

[bitseeker]

An even better memory aid is having an English teacher who for a whole term made the class stand up when he entered the room (as was normal when any teacher entered the room) and instead of the usual "Good morning class.", "Good morning Sir." ritual made us chant in unison "It's with an apostrophe means IT IS!". To this day, fifty odd years later, if I ever have a moment of doubt about how I should punctuate "its" I can hear a whole class chanting in my mind's ear.

Reading you all, I am stunned to realized that it is actually a difficulty for the natives to know which is which ?! 
I mean an apostrophe to me I always learned it was just a short for "it is" or "do not"... so " its " not having an apostrophe obviously has to mean something else, so I  can't possibly mix the two. Maybe I am strange... but I don't see the need to have ritual to remember something as simple ?!

Folks get confused because usually a possessive is formed by appending an apostrophe and the letter "s". Hence, "it's" looks like it could be the possessive form of "it".

What I don't master however... is when people say something like " it's changed " instead of " it has changed "..so that means "has" can represented as an apostrophe like " is ".... or maybe not ? Maybe " it's " always means "it IS "... but in this case I don't understand why they would say " is IS changed " instead of " it HAS changed "... it is  instead of it has.... happens regularly but I don't yet get when one would say " it is changed (for example) " instead of the more normal/usual " it has changed ".....  there must be something to it, either a grammar rule or some habit, but I can't figure it out on my own....

The apostrophe is just a placeholder for the letters that were omitted. So, "it's" can be from "it is" or "it has," since it results from the dropping of the letters between "it" and "s". Context is used to differentiate between the possibilities.

This is how we get contractions such as "I've" for "I have". You can also make the omission at the beginning as in "'twas" for "it was". How about really spicing it up with compound contractions such as "couldn't've" for "could not have"? Fortunately, those aren't commonly used in writing(that I've seen), though they are common spoken (less enunciation effort).

That should teach you : if you want to use a French word, just use it as is and you will be fine, don't try to simplify/modify it !!! 

Ah, but the word 'aid' is not from French, it's from the Middle English 'aiden' (to aid, to help) and the 'en' is a classic Middle English verb ending for active verbs (which itself is a hold-over from Old English). So any spare 'e's flapping about are because the rôle of being an aide is from French, specifically from the military term aide-de-camp. So we have kept the French spelling for the French word, and the English spelling for the English word.

Oh dear, it's more complicated than met the eye, I see ! 

My condolences ...   

Indeed! I admire those who master English as a second (or third, or fourth) language.

[cyclin_al]

That's what we do here... whenever we use an English word, we just use it as is, we don't try to French-ize it...  We pronounce it in all sorts of weird and ridiculous ways but the correct one, we often don't really know what it means... but at least we don't try to modify its spelling. Well, maybe someone can come up with an exception to that but generally pseaking speaking I would say it holds true !

A sandwich is still a sandwich, a weekend is still a weekend. OK you are allowed to write it " week-end " if you want, but still...

Ah, how dare you mention exception without expecting to discover what that exception is!!!

Where you are, the language is supposedly curated by academia.
Here in Quebec, the language police are unapologetically the politicians (http://gdt.oqlf.gouv.qc.ca).  The politicians are having a popularity contest trying to be more French than the French 
Their other popularity contests are even worse; I am not going there.period. 

"le sandwich" is valid in the GWN.
"weekend" is "la fin de semaine" in official quebecois, but canadian french is "la fin de la semaine" ...

A " Voiture " means car most of the time, but here it's also used to refer to a train passenger wagon ! 
That said, I just had a quick look at Google and it appears even in English, at least American English, you can call a wagon a "car", just like us.

"voiture" as a rail car is understood, but the speaker will be treated as a modern elitist snob.
"wagon" as a rail car pronounced with a German accent is the generally accepted term in Quebecois.

--some of these I have learned the hard way