Digital Multimeter Problem "-1" !!!

[battery.13v]

Hello everyone, i have a Digital Multimeter DT9250, so yesterday i was firing a fire with a lighter (Electric Lighter), and i was concerned about the electricity in produce to make the spark .... So i dissassemble it, i bring my digital multimeter, i put it in the highest DC voltage and i test it .... However it suddenly rises to infenity and drops to -1, and stuck in -1 one in all the options(Amperage, Resistance, DC AC voltage, Frequencies, Capacitance) , and the continuity test is the only one who is working now .... Please Help me, i worked for 2 weeks to buy this Multimeter and i don't wan't to throw it to the junk ....

 

[Audioguru]

You zapped your multimeter with the very high voltage from your electric lighter.
My expensive Fluke multimeter says on its cover: 1000V! Your electric lighter probably produced 10,000V or 20,000V.

 

[battery.13v]

You zapped your multimeter with the very high voltage from your electric lighter.
My expensive Fluke multimeter says on its cover: 1000V! Your electric lighter probably produced 10,000V or 20,000V.

So is it repairable ???

 

[BradtheRad]

My inexpensive Ebay DMM has developed a similar problem after several years of working properly. The readout started showing -0.9 at all range settings (when nothing is hooked up). I don't recall doing anything to cause this. The only way I can get a correct voltage or Ampere or ohm value, is to take the readout and add 0.9.

As I understand it, the DMM chip has an ADC which accepts voltages between -.2 and +.2. Normally 0V is read as 0V. It contains resistor networks which bring the various ranges within a window of -.2 and +.2.

Somehow the input now has -0.009 V on it constantly. That is my theory.

If I knew which was the input pin, I think I could change some resistor, to bring it back to 0V.

Or this is another idea. The DMM runs on a single 9V battery. Inside there must be a polarity converter, so it can work with negative polarity. If that is out of adjustment, it might cause -0.009V on the input pin somehow.

It is easy to open up the back of the meter and poke around. However to get inside the front, I must unscrew the pcb. This requires care. The range knob is mounted on springs which can go flying if I'm not careful. Tiny parts can 'disappear', such as brass springy pieces, or ball bearings, etc.

The reading was -0.9 initially. However as months have gone by, it is reduced to -0.8 or -.7. This could be an encouraging sign it will eventually go away.

I agree you zapped it with high voltage. However manufacturers are aware our bodies commonly generate thousands of volts of static charge (especially in cold dry weather). So they need to build in some safeguards against high voltage. A spark lighter might exceed those safeguards.

 

[battery.13v]

My inexpensive Ebay DMM has developed a similar problem after several years of working properly. The readout started showing -0.9 at all range settings (when nothing is hooked up). I don't recall doing anything to cause this. The only way I can get a correct voltage or Ampere or ohm value, is to take the readout and add 0.9.

As I understand it, the DMM chip has an ADC which accepts voltages between -.2 and +.2. Normally 0V is read as 0V. It contains resistor networks which bring the various ranges within a window of -.2 and +.2.

Somehow the input now has -0.009 V on it constantly. That is my theory.

If I knew which was the input pin, I think I could change some resistor, to bring it back to 0V.

Or this is another idea. The DMM runs on a single 9V battery. Inside there must be a polarity converter, so it can work with negative polarity. If that is out of adjustment, it might cause -0.009V on the input pin somehow.

It is easy to open up the back of the meter and poke around. However to get inside the front, I must unscrew the pcb. This requires care. The range knob is mounted on springs which can go flying if I'm not careful. Tiny parts can 'disappear', such as brass springy pieces, or ball bearings, etc.

The reading was -0.9 initially. However as months have gone by, it is reduced to -0.8 or -.7. This could be an encouraging sign it will eventually go away.

I agree you zapped it with high voltage. However manufacturers are aware our bodies commonly generate thousands of volts of static charge (especially in cold dry weather). So they need to build in some safeguards against high voltage. A spark lighter might exceed those safeguards.

Thx a lot Sir ... Anyway i have to buy another one to try to repair old one !