Test Equipment Anonymous (TEA) group therapy thread

[bd139]

8000A supply is a piece of shit. Also watch out as there’s mains on the unmasked board! Really don’t like those meters.

Also the regulator transistors run hot and tend to go low beta so if you’re getting any weird stuff it might be PSRR related. Swap them out for new transistors and sorted.

A potentially enlightening article of the (non)economics of food delivery... https://themargins.substack.com/p/doordash-and-pizza-arbitrage
... always presuming the stated facts are true.

I know this is how finance works but it still makes my skin crawl.

If you think any of that is bad then look at amazon’s retail and cloud operations.

At the end of the day it’s hyper optimised capitalism. It’s a shit show and we have to live in it. If we break it we hurt more people.

Us stupid humans really fucked up didn’t we.

[AVGresponding]

Darn it, just went to register on the site and I get an error message.

Link seems to work for me, maybe your browser blocker is being over-zealous?   

My battery optioned 8000A is still in the repair queue... waiting until I get some more D cells (from work, bollocks to paying for them).
Might try a boost pre-reg + 5V linear reg mod, think I have some jelly-bean boost reg modules though icr the current on them.

[tonyalbus]

Not to bad,
only the 8000A is a bit off

12.08
12.085
12.06
12.09 sometimes 12.08
12.086

8000A's are drifty and the reason is that Fluke went with an unregulated +5V supply. If that 8000A doesn't have the battery option there is a fix. You'll need to install an additional small power transformer because the original can't provide the voltage headroom for a 7805 chip to regulate. I also upgraded the +/- 15V supplies with modern IC's.



Thanks, very hulpful, will open and see.  it was opened, i saw marks..  lets see what we find

[bd139]

Linear reg is a good option. I did an 8010A conversion here: https://www.eevblog.com/forum/testgear/fluke-8010a-mains-only-conversion-and-display-replacement/

Don’t do the display replacement. It hurts 

[Cerebus]

mnem
"To become old and wise, one must first survive being young and stupid." ~mom

"Wisdom comes from experience and experience comes from bad decisions."  ~GreyWoolfe

Based on the decisions of painting 2 rooms, bedroom and large walk in closet area( including concrete floor and ceiling) as a prelude to moving my office from the crappy addition built on the back of the house by the 3 stooges to actually now being in the house under air con instead of a window unit.  We won't mention the fact that I farkin' hate painting.  NO, we won't.

Precisely why last time I had any household painting to do I wheeled out the big compressor and the HVLP spray gun. Spent a couple of hours slathering masking tape and polythene sheet around and then about 30 minutes per coat to paint a whole room. Turns out that shooting emulsion (latex) paint is a doddle compared to any of the fussy shiny finishes one normally associates with spray guns once you get the viscosity right and pop in a bit of drying retarder.

[tggzzz]

sorry bout the big picture... just finding out the settings ...

FYI, there are three aspects to this: how many bytes, how many pixels, and the size rendered on the screen.

Normally before posting I use an image editor to crop so that only the interesting bits are seen, then reduce the larger dimension to 1024 or 640 (or even 480) as appropriate. How wide it appears on the screen can be defined by using the markup

Code: [Select]

[img width=1234]http://...[/img] or

Code: [Select]

[img height=1234]http://...[/img] tags.

BTW, welcome - the natives are friendly, especially to fellow sufferers addicts.

Now, back to making a battery for my Tek 1502...

[tggzzz]

8000A's are drifty and the reason is that Fluke went with an unregulated +5V supply. If that 8000A doesn't have the battery option there is a fix. You'll need to install an additional small power transformer because the original can't provide the voltage headroom for a 7805 chip to regulate. I also upgraded the +/- 15V supplies with modern IC's.

How much voltage headroom is there and what is the current? 78xx have a notoriously high dropout voltage, whereas more modern linear regs can be better in that respect.

If that would be sufficient to avoid replacing the transformer, that would be preferable.

TAoE3 notes:
3-term “lower dropout” (adj & fixed)
pos: LM1117, LT1083-85
3-term fixed & 4-term adj “true LDO”
pos: LT1764A/LT1963 (BJT); TPS744xx (CMOS)
neg: LT1175, LM2991 (BJT); TPS7A3xxx (CMOS)
and lists many more in table 9.3 on p6114.

[med6753]

8000A's are drifty and the reason is that Fluke went with an unregulated +5V supply. If that 8000A doesn't have the battery option there is a fix. You'll need to install an additional small power transformer because the original can't provide the voltage headroom for a 7805 chip to regulate. I also upgraded the +/- 15V supplies with modern IC's.

How much voltage headroom is there and what is the current? 78xx have a notoriously high dropout voltage, whereas more modern linear regs can be better in that respect.

If that would be sufficient to avoid replacing the transformer, that would be preferable.

TAoE3 notes:
3-term “lower dropout” (adj & fixed)
pos: LM1117, LT1083-85
3-term fixed & 4-term adj “true LDO”
pos: LT1764A/LT1963 (BJT); TPS744xx (CMOS)
neg: LT1175, LM2991 (BJT); TPS7A3xxx (CMOS)
and lists many more in table 9.3 on p6114.

As I recall the unregulated +5V measured only about +4.75V so unless you want to go a more complex buck/boost circuit a separate transformer looks mighty attractive.

[mnementh]

"There's three kinds of people. Those that learn by watching someone else, those that learn (by doing) themselves, and then there's the guy who has to pee on the electric fence!" 

I've been all three. In all honesty, the last is the kind of lesson that usually makes for the most memorable stories.

mnem
"Learning is just discovering what you already know.
 Doing is demonstrating that you know it.
 Teaching is showing others that they know just as well as you.
 We are all learners, doers, teachers."

[AVGresponding]

8000A's are drifty and the reason is that Fluke went with an unregulated +5V supply. If that 8000A doesn't have the battery option there is a fix. You'll need to install an additional small power transformer because the original can't provide the voltage headroom for a 7805 chip to regulate. I also upgraded the +/- 15V supplies with modern IC's.

How much voltage headroom is there and what is the current? 78xx have a notoriously high dropout voltage, whereas more modern linear regs can be better in that respect.

If that would be sufficient to avoid replacing the transformer, that would be preferable.

TAoE3 notes:
3-term “lower dropout” (adj & fixed)
pos: LM1117, LT1083-85
3-term fixed & 4-term adj “true LDO”
pos: LT1764A/LT1963 (BJT); TPS744xx (CMOS)
neg: LT1175, LM2991 (BJT); TPS7A3xxx (CMOS)
and lists many more in table 9.3 on p6114.

As I recall the unregulated +5V measured only about +4.75V so unless you want to go a more complex buck/boost circuit a separate transformer looks mighty attractive.

I just opened mine up to have another peek, and the battery is completely phkt, there must be a drain even switched off.

On the battery option the +/-15V are derived from the +5V via an onboard switcher, which can't help the situation any.

Give me a few minutes to set up, as I'm three deep into my Moscow Mules and I'd rather not electrocute meself, so extra care and setup time needed.

[mnementh]

The draw of a McDonalds in the midst of a lockdown. Essex has 4 branches which have reopened for drive through only, and whats more all 4 are in Chelmsford and here is the scene at 1 of them, located on an industrial estate, another is in the middle of a retail park which has a number of food outlets on it which also saw such queues and complaints from these other stores as their customers could not get the car park due to the massive queue for McDonalds, which even saw the Police being called to try to resolve the madness.

https://www.essexlive.news/news/essex-news/mad-queues-chelmsford-mcdonalds-drive-4152596

Interesting. Up here, large chain drive-thrus remained open during the quarantine, though with strict safety guidelines on employees exhibiting any symptoms, and regular changing of gloves, masks, and maintaining distance. Shocking that we were able to flatten the curve...

In true Red Greene ingenius Canuck style, several local establishments resolved the issue of handling card payments at a distance by zip-tying the CC terminal to the end of a hockey stick, which was then extended through the window for the customer to use. 

mnem

[tggzzz]

Heads up, in the UK at least it is a bank holiday weekend - so fleabay has max sellers fee of £1 until the end of the month.

So competing for my time is:

• getting effing Win10 installed
• finding out about swift nesting boxes that I could fit under the eaves (work is restarting on the outside of my house, so the scaffolding won't be up forever, I hope)
• cutting grass, brambles, etc
• repairing my newsfox rss reader, which has just blown up
• swapping a battery holder for my Tek 1502, ready for fleabaying
• getting a description of my 2465dms for fleabay, and working out shipping costs
• inevitable family crap
• daring to poke around in a faulty 1kV PSU; no schematics, no indication of how to connect it to external equipment (other than the way it is currently connected)

Just as well I'm part of the idle retired.

Well, that's "1" sorted, thanks to bd, ignoring all the crap on all the guides on the net, and using NTFS on the usb stick. "1" now mutates into "installing usable operating systems alongside Win10". I wonder how long Win10 will operate; it thinks I don't have an internet connection

Sorting "4" was delightfully easy. Locate a likely looking directory in a backup, and cp -r that to the normal place. Now how easy wouldn't that be in Windows? Which bits of That Big Mistake (the registry) have to be twiddled, and how do you resurrect it if you screw up?

Can't put off measuring the house eaves for "2" much longer I'll have a my third cup of coffee first, then I'll have to go to the post office to get milk and maybe other things the local supermarket doesn't have anymore (e.g. eggs!).

Still managing to avoid "2", this time by completing "5".

But that's given me an almost uncontrollable urge to dissect two 8-cell NiCd batteries, and spark them together into a 9-cell NiCd, so that I can complete the rebuilding of my Tek 1502's battery cage. I feel a trip to my local hackspace is in the offing, to use their spot welder.

Done. "5" that is. I started "2", but found my camera battery was flat, and that was a sufficient excuse to put it off.

Remaking the battery pack was surprisingly fun and satisfying. New tagged[1] NiCds are expensive, around £30 a set, so I bodged my personal Tek 1502 with NiMH cells. But then a few months ago I bought ten 8-cell NiCd batteries for about £15. They were made in 2014 and "expired" in Nov-19. Still better than the original NiCds or NiMHs

Remaking involved twisting the tags off, and re-attaching new ones so the cells are further apart and will fit in that 1502 battery holder. That wouldn't have been possible except that there is now a battery welder available to me, and it is quite fun to use.

Regrettably I can't use 18 of the cells in my bomb-proof £0.99 Fluke 8125A nixie meter, since they are too large. Fortunately that fires up without them, unlike the 1502.

[1] tagged so they can be connected with wires in the strange battery holder. The "strange" is superfluous: everything about the 1503 battery charger cum PSU is strange. Start with a PUJT, and see if you can understand how it works

[Cerebus]

In true Red Greene ingenius Canuck style, several local establishments resolved the issue of handling card payments at a distance by zip-tying the CC terminal to the end of a hockey stick, which was then extended through the window for the customer to use. 

Scandalous! Everybody knows you're supposed to do that with HPHT*.

*Hot Pink Hockey Tape

[Specmaster]

Darn it, just went to register on the site and I get an error message.

Link seems to work for me, maybe your browser blocker is being over-zealous?   

My battery optioned 8000A is still in the repair queue... waiting until I get some more D cells (from work, bollocks to paying for them).
Might try a boost pre-reg + 5V linear reg mod, think I have some jelly-bean boost reg modules though icr the current on them.

I think maybe it might be something to do with Virgin Media, running Windows defender as firewall etc, everything is OK there but which ever way I attempt to get registered with PicGifs.com, I get the following result.

Running Firefox or Chrome.

[mnementh]

All that for a McD's? Gee, and I thought only Americans were stupid. 

We rank at least along side you guys if not further down the toilet at the moment

Welcome to the toilet. 

So very glad to NOT be living in the asshole of America right now. New record numbers of new cases and deaths almost daily. 

mnem

[mnementh]

state of pennsylvania published this graph yesterday.

hmmmmmm.  might be able to get a haircut soon.

Yep, might happen here too. My hair is the longest it's been since the last century. 

Just buy your self a set of electric clippers with the clip on plastic guides that will allow you to select the length of the remaining hair. My sons and I all use them and we have a number 2 all over, so that we are not quite bald afterwards. Depending on the cost of a haircut in your location, they will soon repay the cost. For us, with the average price around here for a haircut being £15 each, the cost was saved instantly as I only paid £12 for the clippers and we have them so far used them at least 8 times now, laughing all the way to the bank 

I bought these off Amazon when I first got to the GWN; cost US$14 with Prime next day thanks to not coming with a MFT of stupid plastic crap add-ons you never use. Honestly, better working clippers than the $45 CONAIR/WAHL ones we left behind. Top blade ceramic, height adjuster NOT on the side where you constantly whack it, and I've charged it 3 times since we got it. Still sharper than the CONAIR was brand-new.

My son prefers the buzz-cut in the summer, so we just kept doing that and trimming baby grrl's bangs (with those scissors) all winter. Paid for itself a dozen times over by now.

Amazon doesn't show them available anymore; but I'm sure someone is selling them under a different brand now.

mnem
moo?

[AVGresponding]

I think maybe it might be something to do with Virgin Media, running Windows defender as firewall etc, everything is OK there but which ever way I attempt to get registered with PicGifs.com, I get the following result.

Running Firefox or Chrome.

Hmm, maybe I should have read your post more carefully; I never tried to register, I just copy/pasted links to any smileys I liked into notepad...   


Well, as for the 8000A, I think it proves that anyone, even Fluke, can make a bit of a dog...

The fooked batterria was holding the 5V to 3.3V rms with a 2V pk-pk ripple...   

Unsoldered it and stuck a 12V supercap in, just to look at float V, and currents.

Switched off, the charge V climbs to, well, I chickened out at 10V, I didn't want my supercap to go bang.
Switched on, it hovers around 7.5V so I guess the battery just got murdered to death by the "charger".

The off current is around 0.1uA, so that shouldn't be a problem.
The on current though, wtf! 600mA or so, and that's without measuring anything, feck knows what it'd be with all the damn segments lit!   

Going to have to put a bit more thought into a better power supply than I expected, good thing I only have 2 brand new D cells, so there's no rush.

[mnementh]

No freaking way. The LAST time I had a crew cut was in Boy Scout camp in 1965. 

No haircut or -style can destroy a raving beauty. 

Kiss my ass. 

Not even with rented lips. 

mnem
 

[Specmaster]

I think maybe it might be something to do with Virgin Media, running Windows defender as firewall etc, everything is OK there but which ever way I attempt to get registered with PicGifs.com, I get the following result.

Running Firefox or Chrome.

Hmm, maybe I should have read your post more carefully; I never tried to register, I just copy/pasted links to any smileys I liked into notepad...   


Well, as for the 8000A, I think it proves that anyone, even Fluke, can make a bit of a dog...

The fooked batterria was holding the 5V to 3.3V rms with a 2V pk-pk ripple...   

Unsoldered it and stuck a 12V supercap in, just to look at float V, and currents.

Switched off, the charge V climbs to, well, I chickened out at 10V, I didn't want my supercap to go bang.
Switched on, it hovers around 7.5V so I guess the battery just got murdered to death by the "charger".

The off current is around 0.1uA, so that shouldn't be a problem.
The on current though, wtf! 600mA or so, and that's without measuring anything, feck knows what it'd be with all the damn segments lit!   

Going to have to put a bit more thought into a better power supply than I expected, good thing I only have 2 brand new D cells, so there's no rush.

Yes, I too can copy and paste, but thought it might be an idea to register if it then gives the ability to use the search box facility to find smileys of the type required.

On the 8000A, that 600mA seems to be excessive surely?

[mnementh]

mnem
"To become old and wise, one must first survive being young and stupid." ~mom

"Wisdom comes from experience and experience comes from bad decisions."  ~GreyWoolfe

Based on the decisions of painting 2 rooms, bedroom and large walk in closet area( including concrete floor and ceiling) as a prelude to moving my office from the crappy addition built on the back of the house by the 3 stooges to actually now being in the house under air con instead of a window unit.  We won't mention the fact that I farkin' hate painting.  NO, we won't.

Precisely why last time I had any household painting to do I wheeled out the big compressor and the HVLP spray gun. Spent a couple of hours slathering masking tape and polythene sheet around and then about 30 minutes per coat to paint a whole room. Turns out that shooting emulsion (latex) paint is a doddle compared to any of the fussy shiny finishes one normally associates with spray guns once you get the viscosity right and pop in a bit of drying retarder.

I prefer Rodney Dangerfield's solution:

"I was walking down the street in Vegas, and a hooker tells me 'I'll do anything you want for $50!' So I gave her the money and said 'Paint my house.' "

mnem

[BU508A]

No freaking way. The LAST time I had a crew cut was in Boy Scout camp in 1965. 

No haircut or -style can destroy a raving beauty. 

Kiss my ass. 

Not even with rented lips. 

Ah, come on! Med asked soooo nicely.     

[mnementh]

*Throws $50 at BU508A*

You know what to do...

mnem
 

[mnementh]

In true Red Greene ingenius Canuck style, several local establishments resolved the issue of handling card payments at a distance by zip-tying the CC terminal to the end of a hockey stick, which was then extended through the window for the customer to use. 

Scandalous! Everybody knows you're supposed to do that with HPHT*.

*Hot Pink Hockey Tape

They tried that; people bitched they couldn't use the keys. Damned selfish bastards want EVERYTHING... next they'll be bitching they need to see the screen, too. *rimshot*

mnem
Zip ties are the new NASCAR tape.

[BU508A]

*Throws $50 at BU508A*

You know what to do...

Ha, nice try but wrong continent.   

Edit:

May I suggest that we would use  something like this instead?   

[mnementh]

Hey, they're YOUR lips... go crazy. Maybe even try a little tongue...

mnem
I'd pay to see that.