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full deflection of analogue multimeter needle?

Hi,
I accidently kept the dial at 25ma, instead of 250v ac of my analogue multimeter, the needle jumped twice, i realised my mistake and immediately disconnected, the problem now is when ever i check any reading including ohms check, the needle deflects fully, any idea what  i must have damaged.

Hi,
I just added the front and back of the PCB, if u gentlemen could identify, the shunt resistor and the current limiting resistor, will be of great hep

Yes, you've ruined at least one of the shunt resistors. It sounds like its open circuit.

Its an easy mistake to make with any meter unfortunately.
patrickvaz (author) 3 years ago
HI,
the 15 ohms resistor just above the red wire happened to be open, replaced the same and meter with little adjustments came back to life, thanks one and all for your support.
NachoMahma3 years ago
. As steveastrouk says, you've probably fried the meter. I try to keep a cheap ($10-25) DMM on-hand to make quick measurements that don't need to be all that accurate (Do I have 120VAC or 0VAC at the wall socket? Do I have continuity or an open? Is my car battery at 13VDC or 8VDC?)
It MIGHT be repairable, if its jsut the resistor.
patrickvaz (author)  steveastrouk3 years ago
HI,
which is the shunt resistor in the above resistors.
There are many resistors in there which it could be, I can't identify it from here. You'll have to try each one,

If you disconnect the meter movement, you can measure the resistors in-situ without lifting the ends.

Good luck


Steve
patrickvaz (author)  steveastrouk3 years ago
Hi,
Iam also arranging a meter 2morrow, if u could identify the resistors i need to check will keep u posted. and also there is no damage on the track at 110clock, i removed the resistor to check the same.
framistan3 years ago
I am familiar with this. I used to repair some MICRONTA (radioshack" meters for the cable-tv technicians i worked with. One of the resistors is burned "open". You will need another ohm meter to find it. One problem with finding it is the color codes on these resistors is difficult to read because they use ONE-PERCENT tolerance flame-proof resistors. If you have another similar meter, you can compare resistor readings from a good meter to your bad one. or... It will likely be a resistor of LOW value like ONE ohm or TEN ohms that is opened up. Since your meter movement is still MOVING... the meter is repairable. Sometimes the meter movement will be destroyed also when making the mistake you made... then the meter is TOAST. You have discovered the MAIN reason to upgrade to a digital meter. They are 99 percent LESS LIKELY to be damaged by these kind of mistakes. As long as you dont put the red probe to AMPS-jack... then try to measure VOLTS... you will not hurt a digital meter. Digital meters are so cheap now, you might just need to put out the ten bucks and buy one. If the meter you are working on is a SIMPSON brand.. I never had any luck fixing one of those. Good luck to you
...A digital meter is at least as easy to fry as an analogue one, just differently.....
I forgot to mention also about the small "GMA" size fuses that also may be in your meter that might have blown. You should check that FIRST.
Can you beg or borrow another meter ? You're going to have to check the parts. There are not obviously damaged ones.

Is there a track blown at about "11 O'Clock" , near the switch contacts ????

Steve
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