Poll

How many cycles will the KeySight U1281A's detent spring last?

0-2000
7 (17.9%)
2k-4k
5 (12.8%)
4k-8k
14 (35.9%)
8k-16k
7 (17.9%)
>16k (most rubust meter ever made)
6 (15.4%)

Total Members Voted: 36

Author Topic: Handheld meter robustness testing  (Read 1149207 times)

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Offline malagas_on_fire

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Re: Handheld meter electrical robustness testing.
« Reply #3425 on: June 16, 2019, 10:46:48 am »
Ohh crap was  the leads or input jacks ? Or is the default error message for anything bad ?

Leads or Fuse error message pops up if you're not in the amps range dial with a lead in the amps input, or you're in the amps range and you have no lead in the amps input or you have a bad fuse.
I get that when I clean the input jack on my 189 with a Q-tip with too much rubbing alcohol, until it dries out.  I think the condensation shorted the amps range input sensor.

Its interesting that the 189 specs have a very wide operating temperature range of -20°C to +55°CC, and even gives you a temperature coefficient for measurement at <18 °C or >28 °C.      Such detail is probably one of the reasons Fluke has become a standard in U.S. Industry.   
It did seem to fall out of the 20 count spec for some duration... I'm guessing due to the condensation? I wonder what parts are affected by it... I'm guessing an analog part like the PTC?  Or more generally some current leak on the board in the analog input section.  I bet some insulating coating on the board can eliminate the condensation effect.
 



One of the interesting things of the manual is there is no mention to water resistance and yes there were water resistant watches back then, but check in the Physical Specifications the humidity ranges , it seems to be high for it's time as i repeated (sorry for this )in a comment on youtube, so probably the meter was ahead of it's time when it was developed / presented. 

Check the specs for the first model of the 87V ... they are the same  in terms of temperature and humidity ranges

« Last Edit: June 16, 2019, 10:52:57 am by malagas_on_fire »
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Offline joeqsmithTopic starter

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Re: Hear kitty kitty kitty, nope not that kind of cat
« Reply #3426 on: June 16, 2019, 01:21:53 pm »
...A few good articles if you are interested:

Just FYI the 2nd and 3rd links didn't work for me.

Not surprised.  It's an old post and the internet is not constant.  If you are planning to keep an updated list for links on safety, here is one you may want to add:   
https://brainfiller.com/arcflashforum/

I'm a bit surprised with the amount of discussions on meter safety that no one took the lead to create a thread for it.   

Offline malagas_on_fire

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Re: Handheld meter electrical robustness testing.
« Reply #3427 on: June 16, 2019, 04:02:57 pm »
There is this thread but maybe it's nothing compared to what is discussed, tested here, since it is a specific target multimeter thread

https://www.eevblog.com/forum/testgear/a-list-of-multimeters-that-do-not-appear-to-meet-their-claimed-safety-specs/

Now to make one similiar as yours it would require someone maybe to build similar test jig, test equipment,DMM's,  skillset, etc Its a unique thread where you pick up something that was not yet explored at diy world on Handheld meters.


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Offline malagas_on_fire

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Re: Handheld meter electrical robustness testing.
« Reply #3428 on: June 16, 2019, 04:31:48 pm »
By the way here is an update for the battery testing on the UT204A in the DC 40 Amp's. Now there are not much of losses to care about from the previous experience with garbage crocodile cables :S 0.75m2 + crimped terminals + banana jacks .. 3.333 Ohms between power supply and meter. better measure voltage on input jacks with uni-t 50b ..[EDIT] its 8.97V on input jacks so it is much lower... need more resolution :D but this is an improvement.

« Last Edit: June 16, 2019, 04:41:13 pm by malagas_on_fire »
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Offline malagas_on_fire

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Re: Handheld meter electrical robustness testing.
« Reply #3429 on: June 16, 2019, 04:49:07 pm »
By the way here is an update for the battery testing on the UT204A in the DC 40 Amp's. Now there are not much of losses to care about from the previous experience with garbage crocodile cables :S 0.75m2 + crimped terminals + banana jacks .. 3.333 Ohms between power supply and meter. better measure voltage on input jacks with uni-t 50b ..[EDIT] its 8.97V on input jacks so it is much lower... need more resolution :D but this is an improvement.

here is the measurement taken on the input jacks with DUT , voltage is the same in both points .

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Offline malagas_on_fire

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Re: Handheld meter electrical robustness testing.
« Reply #3430 on: June 20, 2019, 10:39:30 pm »
Now this is a new thing.... a uni-t with two input jacks and inverted display.... ut123 ... is this the one who would lived up to the transient generator?
 It is so damn simple... a copy cat of some meter that we know...
https://www.ebay.com/itm/UNI-T-UT123-Digital-Color-Screen-High-Accuracy-Multimeter-for-Home-Industry-P2C9/382971551604?hash=item592ae21f74:g:FkcAAOSwbINc5rcR

... besides the ut210E which is in fact very good...
« Last Edit: June 20, 2019, 10:46:30 pm by malagas_on_fire »
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Offline windsmurf

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Re: Handheld meter electrical robustness testing.
« Reply #3431 on: June 21, 2019, 12:42:38 am »
Ohh crap was  the leads or input jacks ? Or is the default error message for anything bad ?

Leads or Fuse error message pops up if you're not in the amps range dial with a lead in the amps input, or you're in the amps range and you have no lead in the amps input or you have a bad fuse.
I get that when I clean the input jack on my 189 with a Q-tip with too much rubbing alcohol, until it dries out.  I think the condensation shorted the amps range input sensor.

Its interesting that the 189 specs have a very wide operating temperature range of -20°C to +55°CC, and even gives you a temperature coefficient for measurement at <18 °C or >28 °C.      Such detail is probably one of the reasons Fluke has become a standard in U.S. Industry.   
It did seem to fall out of the 20 count spec for some duration... I'm guessing due to the condensation? I wonder what parts are affected by it... I'm guessing an analog part like the PTC?  Or more generally some current leak on the board in the analog input section.  I bet some insulating coating on the board can eliminate the condensation effect.
 



One of the interesting things of the manual is there is no mention to water resistance and yes there were water resistant watches back then, but check in the Physical Specifications the humidity ranges , it seems to be high for it's time as i repeated (sorry for this )in a comment on youtube, so probably the meter was ahead of it's time when it was developed / presented. 

Check the specs for the first model of the 87V ... they are the same  in terms of temperature and humidity ranges

I'm more convinced now that condensation on the board likely made the 189 go out of spec... the "Leads or Fuse error" should only ever occur with the dial in the amps measurement position.  Plugging a lead into the amps jack while in the voltage measurement causes a "Leads error" without the "of Fuse," so some kind of current leak around the dial wipers probably occurred.   

 

Offline windsmurf

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Re: Handheld meter electrical robustness testing.
« Reply #3432 on: June 22, 2019, 11:06:02 pm »
I'm more convinced now that condensation on the board likely made the 189 go out of spec... the "Leads or Fuse error" should only ever occur with the dial in the amps measurement position.  Plugging a lead into the amps jack while in the voltage measurement causes a "Leads error" without the "of Fuse," so some kind of current leak around the dial wipers probably occurred.

Thank you Joe for the new part 2 video with humidity enclosure and test, and pointing out it was a "Leads" error, indicating it detected a lead inserted in the amps jack, and not a "Leads or Fuse" error which should only happen with the dial in the amps section.   

So humidity probably did affect the meter in the 1st test with the jacks getting condensation and shorting the sensor.  Still not sure if it was the thermal differential or condensation that caused it to go out of spec in the 1st video but my hunch is, condensation played a role.  The 2nd test seemed to stay in spec enclosed in the ziplock... doing a resistance test which intuitively would be affected to a greater extent by condensation on the board.

I've seen some 87's and 189's input sensor malfunction due to moisture, or fail due to corrosion or debris/gunk between the board and the input jack assembly so that seems to be a weak spot of Flukes where moisture can get trapped.
 


 

Offline joeqsmithTopic starter

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Re: Handheld meter electrical robustness testing.
« Reply #3433 on: June 24, 2019, 01:28:34 am »
No problem.  Its one of those things that we could all guess and be fairly confident that it was moisture causing it but it was easy enough to try this simple test. 

I doubt you would find many cases where people are trying to take measurements when the temperature is not stable.   Well, that is when you are looking for very small effects.   

One thing is certain and that is the box with the stacked peltiers will drive these meters with the camera to much lower temperatures than I could previously reach.  In the end, that was my goal. 

Offline joeqsmithTopic starter

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Re: Handheld meter electrical robustness testing.
« Reply #3434 on: August 27, 2019, 12:07:46 pm »
I doubt I will try and confirm this but if it's true, it's been a long time coming.   To be clear, Gossen has never contacted me about this meter beyond the original posts. 

If they have changed the design, it's too bad they didn't send me one.  I would have repeated all my tests on it, including running RF susceptibility ($$$+++).   They could have redeemed themselves, at least in my eyes.   

One thing it shows is that one competent EE with a tiny channel but with honest, detailed reviews can actually get a company like Gossen to make a change.   That's the only time, but I'll take it.   :-DD

https://www.youtube.com/watch?v=Jf_9XWL3TD8&lc=z225ulhytqmfe5jro04t1aokgym3ty4x4pxmdgdysnmlbk0h00410.1566905126264437

Offline MacMeter

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Re: Handheld meter electrical robustness testing.
« Reply #3435 on: August 27, 2019, 12:25:27 pm »
I doubt I will try and confirm this but if it's true, it's been a long time coming.   To be clear, Gossen has never contacted me about this meter beyond the original posts. 

If they have changed the design, it's too bad they didn't send me one.  I would have repeated all my tests on it, including running RF susceptibility ($$$+++).   They could have redeemed themselves, at least in my eyes.   

One thing it shows is that one competent EE with a tiny channel but with honest, detailed reviews can actually get a company like Gossen to make a change.   That's the only time, but I'll take it.   :-DD

https://www.youtube.com/watch?v=Jf_9XWL3TD8&lc=z225ulhytqmfe5jro04t1aokgym3ty4x4pxmdgdysnmlbk0h00410.1566905126264437

Of course they won’t send you a revised meter, they don’t want you to find any more issues!
GREAT job, watched the old video again, amazing amount of custom work as well as testing and of course your own, unpaid time and labor. But in the end.... CONGRATULATIONS on getting a bit of satisfaction.
 

Offline joeqsmithTopic starter

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Re: Handheld meter electrical robustness testing.
« Reply #3436 on: August 27, 2019, 11:21:50 pm »
If they used NETIC as claimed, and basically replicated my changes, it's hard to believe I would have found anymore problems.   Then again, had they sent me one, I may have ran the 50,000 life cycle test on the rotary switch.  It would have been the first time I running one with a shutter.   So maybe your right.   

Maybe one day we may see another company as confident as Brymen is with their products.   Confidence comes from testing and with the high end Gossen being released with such blatant problems, maybe they just don't do a lot of testing.    Hard to say.  Hope they made the changes.  Hope the relays no longer change states with a simple hanger next to them.   Hope we saved someones life. 
 
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Offline rsjsouza

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Re: Handheld meter electrical robustness testing.
« Reply #3437 on: August 28, 2019, 01:31:46 pm »
If the assertion it true, it took them 1-1/2 years to silently release the fix. taking into account the change in manufacturing and compliance tests, I feel this took a bit longer than expected, but oh well. 

My suspicion is similar to yours: they buried their head on the sand until one of their big customers that did not suffer from "Joe derangement syndrome" reported the same issue.  :-DD

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Offline joeqsmithTopic starter

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Re: Handheld meter electrical robustness testing.
« Reply #3438 on: August 28, 2019, 04:53:30 pm »
The last time I wrote them directly, the German office sent me back to the US distributor.   After the way the distributors behaved, I see no reason to go down that path again.   You want to talk about a total lack of integrity.   

https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1221413/#msg1221413
 
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Offline joeqsmithTopic starter

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Re: Handheld meter electrical robustness testing.
« Reply #3439 on: October 31, 2019, 11:38:31 pm »
It's been over two years since I first looked at the 121GW prototype.   UEI has had plenty of time to iron out any problems / shortcomings with the meter.   There's a lot to cover so expect a series of videos.

Offline rsjsouza

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Re: Handheld meter electrical robustness testing.
« Reply #3440 on: November 01, 2019, 12:44:11 am »
It's been over two years since I first looked at the 121GW prototype.   UEI has had plenty of time to iron out any problems / shortcomings with the meter.   There's a lot to cover so expect a series of videos.
You are baaaaaack! Nice!
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Oh, the "whys" of the datasheets... The information is there not to be an axiomatic truth, but instead each speck of data must be slowly inhaled while carefully performing a deep search inside oneself to find the true metaphysical sense...
 
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Offline joeqsmithTopic starter

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Re: Handheld meter electrical robustness testing.
« Reply #3441 on: November 04, 2019, 03:12:38 am »
The 121GW Production DMM,  Part 1, Initial checkout and tear down   

They are hardly out of the box and already there are a few unexpected surprises.   


Offline okurka

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Re: Handheld meter electrical robustness testing.
« Reply #3442 on: November 04, 2019, 06:59:25 pm »
The 121GW Production DMM,  Part 1, Initial checkout and tear down   

They are hardly out of the box and already there are a few unexpected surprises.   


Where did you buy those from and when?

They still have the old firmware.
 

Offline joeqsmithTopic starter

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Re: Handheld meter electrical robustness testing.
« Reply #3443 on: November 05, 2019, 12:53:11 am »
The 121GW Production DMM,  Part 1, Initial checkout and tear down   

They are hardly out of the box and already there are a few unexpected surprises.   


Where did you buy those from and when?

They still have the old firmware.
These were purchased from the EEVBlog store about a week ago.

I think all the 121GW followers are aware that 1.57 is not the latest firmware but personally, I think the real question is why they are continuing to ship with the old firmware.   I understand that it can be updated but it's a handheld meter, not a PC.  If the changes truly do provide a significant improvement without introducing major problems, I would have expected it to be preloaded.   

That said, the goal of this first part was to perform a basic functional test of the hardware to make sure its in working order.   I will more than likely dedicate a full segment to the firmware alone.   For now, I plan to stay focused on the hardware. 
 
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Offline Mr.B

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Re: Handheld meter electrical robustness testing.
« Reply #3444 on: November 05, 2019, 01:08:36 am »
Bookmarked to follow the 121GW series.
Thanks Joe.
I approach the thinking of all of my posts using AI in the first instance. (Awkward Irregularity)
 

Offline rsjsouza

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Re: Handheld meter electrical robustness testing.
« Reply #3445 on: November 05, 2019, 10:12:51 am »
The 121GW Production DMM,  Part 1, Initial checkout and tear down   

They are hardly out of the box and already there are a few unexpected surprises.   


Where did you buy those from and when?

They still have the old firmware.
These were purchased from the EEVBlog store about a week ago.

I think all the 121GW followers are aware that 1.57 is not the latest firmware but personally, I think the real question is why they are continuing to ship with the old firmware.   I understand that it can be updated but it's a handheld meter, not a PC.  If the changes truly do provide a significant improvement without introducing major problems, I would have expected it to be preloaded..
In my experience it is very difficult to update the firmware in units ready to ship, as the repackaging process can be intricate if there are sealed plastic enclosures, etc.

But I also agree the firmware shouldn't affect so much the functionality flaws seen on the video. The slow auto range is something really obnoxious and, if this is not hardwired on the chipset, it could potentially be improved by different firmware. The inaccurate measurements are more concerning, though.

Unless the firmware update addresses these two issues, I am from the school of thought that, if it is working, don't update.
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Offline malagas_on_fire

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Re: Handheld meter electrical robustness testing.
« Reply #3446 on: November 05, 2019, 11:13:03 am »
Hi there
It was weird how one of the units was glitching, measurement of the 1MOhm resistor. Does it glitches when you turn the rotary switch slow ( if you have re-assembled it) ? Will you try with and without the padding disk to see if has any difference?

Another question does the fw implements debounce for the contacts? 

Thanks for the video.
« Last Edit: November 05, 2019, 11:17:06 am by malagas_on_fire »
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Offline joeqsmithTopic starter

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Re: Handheld meter electrical robustness testing.
« Reply #3447 on: November 05, 2019, 01:22:02 pm »
In my experience it is very difficult to update the firmware in units ready to ship, as the repackaging process can be intricate if there are sealed plastic enclosures, etc.

But I also agree the firmware shouldn't affect so much the functionality flaws seen on the video. The slow auto range is something really obnoxious and, if this is not hardwired on the chipset, it could potentially be improved by different firmware. The inaccurate measurements are more concerning, though.

Unless the firmware update addresses these two issues, I am from the school of thought that, if it is working, don't update.

If you followed my testing of the firmware, they were changing the filters on each new release.   The noise was getting really bad and the AC line rejection was suffering.   I made a few videos showing the effects.    Because I was running all of these tests on the prototype and Dave appeared to be getting frustrated with the amount of information I was posting, I cleared out most of that information to avoid any confusion.    Of course, now we no longer have that problem as these two meters being brand new had better represent the current production.   

I assume the changes to the filters was made in attempt to reduce the settling time but it was making the meter worthless.  I want a fast and accurate meter.  If I have to choose between fast and inaccurate  or  slow and accurate,  hands down I will take accurate every time.   

It appears I gave up testing the firmware at 1.57 so it will be interesting to see how it has changed.   

If you think reprogramming the firmware takes a lot of time, stay tuned for part 2 where I look at the hardware.   The boards have some interesting rework which I dare say required a lot more time than it would take to install the latest firmware.   
 
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Offline rsjsouza

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Re: Handheld meter electrical robustness testing.
« Reply #3448 on: November 05, 2019, 05:51:14 pm »
Thanks for the insights.

If you followed my testing of the firmware, they were changing the filters on each new release.
No, I haven't. Not having the meter my interest flows somewhere else.

The noise was getting really bad and the AC line rejection was suffering.
There's no free lunch. :)

I assume the changes to the filters was made in attempt to reduce the settling time but it was making the meter worthless.  I want a fast and accurate meter.  If I have to choose between fast and inaccurate  or  slow and accurate,  hands down I will take accurate every time.
You can tell that Keysight thinks exactly like you when they designed the U1282A. I only wish they had put the resolution selection on a simple button press like the 87V. It is an excellent meter but &%$@! slow in 4-1/2 mode.

If you think reprogramming the firmware takes a lot of time, stay tuned for part 2 where I look at the hardware.   The boards have some interesting rework which I dare say required a lot more time than it would take to install the latest firmware.
Interesting, although hardware rework was probably done before packaging.
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Oh, the "whys" of the datasheets... The information is there not to be an axiomatic truth, but instead each speck of data must be slowly inhaled while carefully performing a deep search inside oneself to find the true metaphysical sense...
 

Offline joeqsmithTopic starter

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Re: Handheld meter electrical robustness testing.
« Reply #3449 on: November 06, 2019, 12:39:42 am »
Thanks for the insights.

If you followed my testing of the firmware, they were changing the filters on each new release.
No, I haven't. Not having the meter my interest flows somewhere else.

You're going to be very bored with this series then.   Not that my data dumps are all that exciting to begin with.   :-DD

The noise was getting really bad and the AC line rejection was suffering.
There's no free lunch. :)

Maybe they found a way to have their cake and eat it too but from the trend I was seeing, that didn't seem to be the case.    Before installing the new firmware, I plan to repeat some of those noise tests using the older firmware with the new meter and see if the results repeat. 

I assume the changes to the filters was made in attempt to reduce the settling time but it was making the meter worthless.  I want a fast and accurate meter.  If I have to choose between fast and inaccurate  or  slow and accurate,  hands down I will take accurate every time.
You can tell that Keysight thinks exactly like you when they designed the U1282A. I only wish they had put the resolution selection on a simple button press like the 87V. It is an excellent meter but &%$@! slow in 4-1/2 mode.

If noise isn't a problem and you really only need a fast 3.5 digit DMM, I understand Harbor Freight still provides free ones.  :-DD  It will be interesting to see how it plays out. 

If you think reprogramming the firmware takes a lot of time, stay tuned for part 2 where I look at the hardware.   The boards have some interesting rework which I dare say required a lot more time than it would take to install the latest firmware.
Interesting, although hardware rework was probably done before packaging.

If you watched the video, you know the one box had been opened to add the fuses.  As you don't have a meter to try it, you could use Dave's numbers.   

How accessible is it ? I thought it was behind the screwed-down fuse cover.

It is.
It takes less than 20 seconds to remove the holster, undo two screws (metal threaded insert), remove the battery cover and take out the SD card.
Yes, I timed it.
Hardly a chore for anyone who wants to do occasional data logging. And as I said, faster than dicking around with Bluetooth BLE and a ridiculously slow data rate.

If you are doing data logging all the time, I'd recommend buying a proper data logger with the convenient interface of your choice.

What's interesting about his comment is once I had LabView working with the meter,  I never used the SD card to log again.  My only real dicking around was getting my software working.   


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