can't read right number now, is it repairable?

 

Do you mean it was on a current range, but connected to a voltage source?
Does it read correctly on any range?

 

Do you mean it was on a current range, but connected to a voltage source?
Does it read correctly on any range?

Thank you.
Yes, it was connected to a voltage source when sit at current range.
Can't read any thing now, even the R.

 

Probably a blown fuse.

 

Probably a blown fuse.

If you're very, very lucky.
It doesn't sound good.

 

Probably a blown fuse.

Not that.
I replaced the battery, it can measure but the number is wrong, the V12 by another meter was read by it for 10.85, and the 5.05 for 4.57, around 90%, why?

 

Not that.
I replaced the battery, it can measure but the number is wrong, the V12 by another meter was read by it for 10.85, and the 5.05 for 4.57, around 90%, why?

From your description, it is broken. Have you opened it?

 

This meter shares the input across V/Ω/mA, thus it is an easy mistake to do (one more reason to have meters with fully separate input jacks, but that is subject for another discussion).

I would thoroughly inspect its internals and compare to one of the multiple reviews around on the internet.



I find very interesting the measurements indicate only a fraction of the regular voltage - this usually indicates that a thermistor is still warm due to the abuse and it would take only a few minutes for it to get back to its normal resistance. At any rate, I would suspect PTC1 would be the most probable culprit as several ranges are affected (and this seems to be the common element just before the ADC).

I find it hard to believe that one of the input protection clamping diodes/transistors was fried due to the excessive voltage across the shunt resistor. For that to have happened, the fuse would certainly be blown well before that. Although it doesn't hurt to check D3 and D4.

Image credit:

 

It's a good time to buy a new auto-ranging one.

 

It's a good time to buy a new auto-ranging one.

Auto range?! Ugh, cursed invention, always flickering back and forth between ranges rather than giving a reading!

 

From your description, it is broken. Have you opened it?

I didn't open it.

 

This meter shares the input across V/Ω/mA, thus it is an easy mistake to do (one more reason to have meters with fully separate input jacks, but that is subject for another discussion).

I would thoroughly inspect its internals and compare to one of the multiple reviews around on the internet.

View attachment 172673

I find very interesting the measurements indicate only a fraction of the regular voltage - this usually indicates that a thermistor is still warm due to the abuse and it would take only a few minutes for it to get back to its normal resistance. At any rate, I would suspect PTC1 would be the most probable culprit as several ranges are affected (and this seems to be the common element just before the ADC).

I find it hard to believe that one of the input protection clamping diodes/transistors was fried due to the excessive voltage across the shunt resistor. For that to have happened, the fuse would certainly be blown well before that. Although it doesn't hurt to check D3 and D4.

Image credit:

Thank you ,
I'll check it.

 

maybe - I love mine... mine ranges to 60MΩ and it's quick...

Don't you get tired of turning that dial to figure out whether you have an open or you're out of range?

 

I opened the cover and adjust the Trimmer potentiometer made my meter measured V accurate now, but still not be able to measure R.

 

It's a good time to buy a new auto-ranging one.

That won't help when you make the mistake the OP made.

Auto range?! Ugh, cursed invention, always flickering back and forth between ranges rather than giving a reading!

I agree with your sentiment. Autorange is more bother than it's worth.

Don't you get tired of turning that dial to figure out whether you have an open or you're out of range?

Nope. When I studied electronics, analog meters were far more common. We learned to set the range for what we expected to measure.

 

Nope. When I studied electronics, analog meters were far more common. We learned to set the range for what we expected to measure.

Me too I have a bunch of analog ones... My first auto-ranging cured that. Now I can't imagine going back to guessing and turning that dial... There are a few areas where a moving coil display is handy... it's good for representing RMS for AC signals... It's not as fast but a nice representation of information... Perhaps Digital is too fast and detailed to show such information without graphical display. I believe my first MM was from radio shack or Sears along with the Heathkits and stuff like that ...

 

Me too I have a bunch of analog ones...

I still have my first analog meter (an RCA). I have a couple cheap Radio Shack analog meters that I keep in cars so I don't need to worry about having good batteries to measure battery voltage.

 

One place I worked some poor fool grabbed a digital multimeter off a bench and set the range switch to 1000 volts AC. But the fool did not realize that the leads were plugged in to the ten amp current jacks. He put the probes across 480 volts AC, fused at 60 amps. The meter blew up, the probes burned up, and he got his hands burned, all from not bothering to pay attention to what he was doing. AND we lost a $300 multimeter, because it was a good one and none of them were cheap yet. The dummy survived with only minor burns on his hands and no shock, but the meter was totally destroyed. After that I always unplugged the test leads when I was done with the meter.

 

But the fool did not realize that the leads were plugged in to the ten amp current jacks. He put the probes across 480 volts AC, fused at 60 amps.

Inattention to detail can result in one receiving a Darwin Award. It's always preferable for the award to be bestowed upon individuals before they've had a chance to procreate.