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Mike Welch
Joined: 13 Feb 2011
Posts: 272
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 Posted: Thu Feb 24, 2011 9:06 am Post subject: I found some magic smoke |
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List guys, for your amusement;
�
� I know how to hook up a multimeter, but yesterday I was a little too
careless to verify the setting before I tried checking the voltage my
airplane's new battery.
�
� I quickly found out where my multimeter stores it's magic smoke!!� It's near the bottom,
where the leads attach!!� I comes out in large plumes from the lead holes.� Yep, my fairly
new Etec multimeter was toasted, and now it has readings all over the place!� The readings just
jumps around, never settle on any specific number.�� Rats!!
�
� What is especially annoying is we recently found out WalMart evidently doesn't sell this
particular model of�multimeter anymore, and that's too bad, because I really did like it.�
�
� The last time I tried fix the previous multimeter I had, (someone spilled coffee in it) which
was the exact same model, I didn't have much success.� I hoped I could try to fix this one,
maybe with better results this time.
� So, I took this apart yesterday, and found that some kind of large wire/fuse thing got fried,
plus it blew the itty bitty fuse (no biggie on this one).� I got out my soldering iron, fashioned
a similar piece or wire, and removed the old crispy one, scraped away the carbon and gunk, and
replaced it with the new one, and replaced the blown fuse.� Whoa!!� To my surprise, it works
good as new...well, sort of.� It still has that 'magic smoke' smell, but maybe that will remind
me to hook it up properly from now on!!!
�
Mike Welch
�
�
[quote][b]
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handainc(at)madisoncounty
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| Posted: Thu Feb 24, 2011 9:53 am Post subject: I found some magic smoke |
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Hey! I'll try that on mine that doesn't work! The taking apart and repair, that is! Hope I don't discover the magic smoke container! I suspect mine was a WalMart return that had the same treatment you did to yours - and because I didn't use it for several months, didn't discover it was bad until I went to use it with the thermocouple you sent me. That is probably why mine didn't have the thermocouple with it.
If the repair doesn't last, let me know what unit you end up replacing it with. I've been looking for something similar, but haven't found anything yet.
M. Haught
On 2/24/2011 11:02 AM, Mike Welch wrote: [quote] List guys, for your amusement;
I know how to hook up a multimeter, but yesterday I was a little too
careless to verify the setting before I tried checking the voltage my
airplane's new battery.
I quickly found out where my multimeter stores it's magic smoke!! It's near the bottom,
where the leads attach!! I comes out in large plumes from the lead holes. Yep, my fairly
new Etec multimeter was toasted, and now it has readings all over the place! The readings just
jumps around, never settle on any specific number. Rats!!
What is especially annoying is we recently found out WalMart evidently doesn't sell this
particular model of multimeter anymore, and that's too bad, because I really did like it.
The last time I tried fix the previous multimeter I had, (someone spilled coffee in it) which
was the exact same model, I didn't have much success. I hoped I could try to fix this one,
maybe with better results this time.
So, I took this apart yesterday, and found that some kind of large wire/fuse thing got fried,
plus it blew the itty bitty fuse (no biggie on this one). I got out my soldering iron, fashioned
a similar piece or wire, and removed the old crispy one, scraped away the carbon and gunk, and
replaced it with the new one, and replaced the blown fuse. Whoa!! To my surprise, it works
good as new...well, sort of. It still has that 'magic smoke' smell, but maybe that will remind
me to hook it up properly from now on!!!
Mike Welch
[b]
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nuckolls.bob(at)aeroelect
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| Posted: Thu Feb 24, 2011 1:32 pm Post subject: I found some magic smoke |
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At 12:02 PM 2/24/2011, you wrote:
| Quote: | List guys, for your amusement;
I know how to hook up a multimeter, but yesterday I was a little too
careless to verify the setting before I tried checking the voltage my
airplane's new battery.
I quickly found out where my multimeter stores it's magic smoke!! It's near the bottom,
where the leads attach!! I comes out in large plumes from the lead holes. Yep, my fairly
new Etec multimeter was toasted, and now it has readings all over the place! The readings just
jumps around, never settle on any specific number. |
This one?
[img]cid:.0[/img]
| Quote: |
What is especially annoying is we recently found out WalMart evidently doesn't sell this
particular model of multimeter anymore, and that's too bad, because I really did like it. |
Every multi-meter of this genre' has what appears to
be a 'fat wire' jumper on the board that looks something
like this:
[img]cid:.1[/img]
Further, there will be one or more GMA series fuses
in open clips. The 'fat wire' is the high current shunt. It
a special alloy with a callibrated resistance. The really
GOOD ones use manganin wire which offers very low temperature
coefficient of resistance.
The fuse will be a very low current device . . . usually
0.5A or less that protects the lower current ranges from
overload . . . and may protect the ohmmeter circuitry
too.
It sounds like your test leads were set up for a high
current measurement (that is not protected) which
warmed things up rather severely. There's a seller on
Ebay offering the model above for $40 shipping paid.
Bob . . .
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| Description: |
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85.9 KB |
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1935 Time(s) |
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208.58 KB |
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Mike Welch
Joined: 13 Feb 2011
Posts: 272
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| Posted: Thu Feb 24, 2011 2:44 pm Post subject: I found some magic smoke |
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>This one?
>Bob
�
Hi Bob,
�
� Yes, that's the one.�� Yes, the large wire you refer to (shunt) is the one that
got toasted.� Yes, the little fuse was 500mA.� Yes, I accidently tried to measure
the 12V battery's current, although I didn't intend to!
�
� Although I realize my make-shift wire replacement would never pass for any
real calibrated shunt, for what I use the multimeter for, it should be fine.� I don't
generally ever check for current, and even in this case it was an accident.
� I have two other multimeters that I could use if I was especially concerned about
an accurate figure.� As best as I can tell, the resistance function appears to be
unaffected, and that is mainly what�I use this multimeter for.� So far, a random sampling
of various resistors still appear to be as expected.
�
Thanks,�� Mike
�
�
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1933 Time(s) |
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1933 Time(s) |
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handainc(at)madisoncounty
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| Posted: Thu Feb 24, 2011 3:31 pm Post subject: I found some magic smoke |
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joemotis(at)gmail.com
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| Posted: Thu Feb 24, 2011 6:44 pm Post subject: I found some magic smoke |
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You know these cheap throwaway meters work great and can be repaired easily when you goof and are great for lo voltage.You can afford to have them everywhere.
OTH, I would never use or trust any of these cheapies on line voltage or above, even with an immediate pre test that you always should do anyhow. I personally feel that the Fluke 87 is one of the best meters ever and my VOM experience goes back to my EICO handi tester that cost $10 and was a kit. My 260 is still on the bench at the hangar just for the beauty of the fine instrument it is and its linear response.
Anybody here remember T/S 352 B/U Handy Dandy Jungle Jim Multimeter with leads??
Just my .02
On Thu, Feb 24, 2011 at 2:18 PM, Mike Welch <mdnanwelch7(at)hotmail.com (mdnanwelch7(at)hotmail.com)> wrote:
[quote] >This one?
>Bob
�
Hi Bob,
�
� Yes, that's the one.�� Yes, the large wire you refer to (shunt) is the one that
got toasted.� Yes, the little fuse was 500mA.� Yes, I accidently tried to measure
the 12V battery's current, although I didn't intend to!
�
� Although I realize my make-shift wire replacement would never pass for any
real calibrated shunt, for what I use the multimeter for, it should be fine.� I don't
generally ever check for current, and even in this case it was an accident.
� I have two other multimeters that I could use if I was especially concerned about
an accurate figure.� As best as I can tell, the resistance function appears to be
unaffected, and that is mainly what�I use this multimeter for.� So far, a random sampling
of various resistors still appear to be as expected.
�
Thanks,�� Mike
�
�
[b]
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nuckolls.bob(at)aeroelect
Guest
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| Posted: Thu Feb 24, 2011 7:51 pm Post subject: I found some magic smoke |
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| Quote: | Hi Bob,
So far, a random sampling of various resistors still appear to be
as expected.
|
Sounds like you pulled that rabbit out of the hat!
Good job.
Bob . . .
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