Products > Test Equipment

Test Equipment Anonymous (TEA) group therapy thread

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mnementh:

--- Quote from: Ice-Tea on October 18, 2021, 02:15:02 pm ---
--- Quote from: mnementh on October 18, 2021, 01:12:40 pm ---
--- Quote from: Ice-Tea on October 18, 2021, 08:47:38 am ---   Huh?  :wtf:

Opened up an original Fluke battery pack. Crusty as you might expect but... what's that?? Some yellow modling came off, looks suspiciously like a PTC resetable fuse. Might be part of the puzzle.
--- End quote ---
Hey... a Polyfuse buried in the cell pack. Who'd have thunk it...?   ;)
--- End quote ---

I have no idea! Who? WHO I ASK YOU??!?
--- End quote ---

*snerk*   ;) 


--- Quote from: Ice-Tea on October 18, 2021, 02:15:02 pm ---Seriously though, might be part of the puzzle, but there's more to it. I blew one with an original pack as well, even though you could ask yourself the question how good that PTC still is after being soaked in battery puke. Still need to check the replacement packs, don't know if they have it or not. But still, must be more to it. There's a charging regulator there, with a max charging current of 1A. You couldn't blow that sense resistor with 1A, not with 2A either.

The two units I blew the sense resistor on were revived.

Going to set up some working 199Cs to monitor the charging cycles of the others. Or themselves. Oooh, that would be cool.

Another possibility: the charging circuit uses the NTC in the pack to monitor charging. It's possible leaving the back cover up disturbes the thermal balance. Or maybe it's positioned differently in the pack. So many possibilities.
--- End quote ---


Hmmm... Now I've had a chance to RTFM before posting, ( at ME) it's pretty obvious the charging function on this unit is quite a bit more complicated than a simple analog Ni-xx charger.

Pages 3-23 to 3-26 of the SM show a number of things going on; if I'm understanding this correctly, even when the unit is off, all power functions are managed by a dedicated Power ASIC. The following things are monitored, and everything below has to return some valid result or the mask software running in the main D-ASIC will not even wake up from IDLE (INACTIVE) mode:

BattVolt: Battery Voltage at R4112 powers part of the P-ASIC. It then can monitor the following:

BattIdent set by a ID resistor in the pack: Evidently more than one battery type was planned; I'd guess Ni-Cd vs high-capacity Ni-MH. This will affect max charge current and cutoff/trickle mode voltage set by the P-ASIC.

MAINVAL: Voltage from AC adapter/Charger at R4104.

Batt Temp: The NTC in the circuit snippet above.

Charge Current: Measured through R4101, the one which keeps blowing up.

If all monitored points return a valid voltage, then the unit's main D-ASIC starts running and unit enters Charge or Operational & Charge mode (if ON button is pressed) and battery charging begins. Charge current is then managed by the main D-ASIC based on VBatt vs TEMP over time.

According to this material, max charge rate is supposed to be no more than 1A. Obviously, something in the scopemeter's interaction with these aftermarket packs is making it possible for that limit to be grossly exceeded.

I find myself wondering if perhaps the aftermarket packs IDENT resistor is wrong for the cells involved, or if possibly there is some other issue. Maybe something that needs a firmware update? Maybe old noisy power bricks with dried out caps? Maybe nonexistent/wrong/just plain crap Polyfuse? Maybe the TEMP NTC is the wrong type/value/slope?

Maybe the TEMP NTC in the OEM packs is corrupted by electrolyte similarly to the Polyfuse, and the failure mode is actually different there? Same is also possible re the Polyfuse in them as well, now I think of it.

I've attached those pages below as PDF & ODT for easy reference. And here's the full SM again for convenience if someone else wants to kibbutz:

https://elektrotanya.com/fluke_192b_196b-c_199b-c_scopemeter.pdf/download.html

Hope that helps!

mnem
 :-/O

AVGresponding:
Well the connector is just a dc barrel jack so it should be quite easy to check if the PSU is providing the correct voltage. If I'm not mistaken the brick is just a transformer, bridge, and maybe a decoupling cap, so not much to go wrong.

tggzzz:

--- Quote from: Ice-Tea on October 18, 2021, 02:15:02 pm ---
--- Quote from: tggzzz on October 18, 2021, 10:07:43 am ---
--- Quote from: Ice-Tea on October 18, 2021, 08:47:38 am ---On unrelated news: I think I'm done shipping to the UK. Two parcels I shipped over the last two months or so vanished. Passed customs, status set to return straight away after which nobody can find it anymore.

--- End quote ---

Unpleasant.

Out of curiosity, which carrier and what were the postcodes (for anonymity, omit the last two letters).

--- End quote ---

DPD. AB526 and DA51PP. As far from each other as possible, doesn't look like the "local" DPD was ever involved either. Just goes from "at the depot" to "being returned". What I *hate* is that I spend stupid amounts of time filling in contact details (and mine are obviously inlcuded) but they *never* make any attempt to contact you if something is off.

--- End quote ---

DA5 1 is suburban London and unremarkable. AB52 6 is rural Scotland, with many "C2" (skilled manual) inhabitants. So it looks like DPD is the common factor.

I've never had real problems with any carrier delivering my stuff[1] to me; they all seem pretty good including Herpes and Yodel.

The UK currently has a gross shortage of fizzy drinks and lorry drivers. The first is high energy prices -> fertiliser plant shutdown -> no CO2 by product (which is also a problem for food processing, since CO2 is used to "stun" animals before slaughter). The second is claimed by the government to be Covid related, but is more due to brexit and closing borders to foreign workers.

[1] since satnavs and google maps don't recognise a (rather strange) nearby street with a vaguely similar name as mine (X Close is autocorrupted to X Y Street), I often get other people's stuff delivered to me. (The worst such example was full height scaffolding!). I've advised people in the other street to have "opposite the supernarket" as part of their address.

AVGresponding:
Not normally an ebay day, but what the hey:



Someone else buy this so I don't have to: https://www.ebay.co.uk/itm/144244364494





And there's more: https://www.ebay.co.uk/itm/274979911240





How about a meter that says hello to you when you turn it on? https://www.ebay.co.uk/itm/124956903633





I can't be arsed to bid on this so I'll post it here instead: https://www.ebay.co.uk/itm/373757869148





Another of these buggers, the market's getting flooded: https://www.ebay.co.uk/itm/373757088686





A bit crustyburgers, but good for some portable tzzzzt: https://www.ebay.co.uk/itm/255183215502





Baby differential voltmeter: https://www.ebay.co.uk/itm/373757584332





Cheap as chips basic FG with green LEDs: https://www.ebay.co.uk/itm/353728626029





Macaroni reduced in price: https://www.ebay.co.uk/itm/133902254897





Somewhat saltily priced baby Tek: https://www.ebay.co.uk/itm/284491612323





More salty pricing, for an item that myself, factory, and maybe other on here could use. TBH I'd rather make my own than pay that much: https://www.ebay.co.uk/itm/284492325324

AVGresponding:

--- Quote from: tggzzz on October 18, 2021, 04:17:32 pm ---The UK currently has a gross shortage of fizzy drinks and lorry drivers. The first is high energy prices -> fertiliser plant shutdown -> no CO2 by product (which is also a problem for food processing, since CO2 is used to "stun" animals before slaughter). The second is claimed by the government to be Covid related, but is more due to brexit and closing borders to foreign workers.

--- End quote ---

If the lorry driver shortage is due to Brexit, why are they short of them in Germany and especially Poland?

It's a good deal more complicated, and while Brexit has an impact, it's not the sole or even primary reason. The utterly incompetent way it's been handled is probably more to blame, not to mention a number of incidences of apparently deliberate nose/spite/face perpetrated by both sides of the divide.

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