Author Topic: help about multimeter UNI-T UT58C  (Read 1235 times)

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Offline BENAMORMEDTopic starter

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help about multimeter UNI-T UT58C
« on: May 31, 2024, 04:53:07 am »
hello at all
after wrong use the multimeter become unusable

the problem is: multimeter continous beeping on AC or DC and Ohm

all musurement are false

but work in diod mod/buzzer

any help please

thanks
« Last Edit: May 31, 2024, 05:17:21 am by BENAMORMED »
 

Online Overspeed

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Re: help about multimeter UNI-T UT58C
« Reply #1 on: May 31, 2024, 06:45:53 am »
Hello

You need first to open it and search possible burned components or pcb tracks

Regards
OS
 
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Offline BENAMORMEDTopic starter

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Re: help about multimeter UNI-T UT58C
« Reply #2 on: May 31, 2024, 09:53:06 pm »
hello evryone,
thanks for replay

i check the fuse is ok
diode , zener diode ok

No visual burned or damaged component

see attached photos

any suggestion for next step!

thanks for all
« Last Edit: June 01, 2024, 03:42:30 am by BENAMORMED »
 

Offline Poroit

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Re: help about multimeter UNI-T UT58C
« Reply #3 on: June 02, 2024, 03:19:53 am »
Did you apply AC Volts while the meter was on the Ohms Range?
 

Offline BENAMORMEDTopic starter

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Re: help about multimeter UNI-T UT58C
« Reply #4 on: June 02, 2024, 09:20:24 pm »
Hello
Im not sure but may be yes
The buzzer work perfectly in beep mode when i connect the probe

But it beep constantly in the rest of range except the capacity
Any idea!
Thanks
 

Offline Poroit

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Re: help about multimeter UNI-T UT58C
« Reply #5 on: June 03, 2024, 08:31:15 am »
Most multimeters are damaged from users forgetting to switch ranges.

The fuses don't react quickly enough to prevent component damage. 

If you were measuring Resistance and forgot to change ranges before measuring AC Volts then you have taken out a component in the Resistance network.

Similarly if you had your multimeter set to measure DC current and attempted to measure AC Volts, then you will take out a component in the Universal current shunt.
 

Offline Zenith

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Re: help about multimeter UNI-T UT58C
« Reply #6 on: June 03, 2024, 09:06:09 am »
The schematic for the UT58A is available on Elektrotanya.

https://elektrotanya.com/multimeter_ut58a_sch.pdf/download.html#dl

I think there are only small differences between the UT58A, B and the UT58C, which you have. I couldn't find a service manual, but having the schematic for systematic fault finding is a lot better than trying to work things out without one.

You didn't say what the abuse was. If it was applying mains voltage while on the resistance range, it could well have caused widespread damage, which may not be obvious.

It's always worth investigating, because often faults are easily fixed, but I suspect you will have to buy a new meter.

 
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Offline BENAMORMEDTopic starter

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Re: help about multimeter UNI-T UT58C
« Reply #7 on: June 04, 2024, 01:51:58 pm »
hello
i check the part of buzzer ic 4011 and 358

all the resistance are ok

no short in capacitor

 

Offline alonsojar

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Re: help about multimeter UNI-T UT58C
« Reply #8 on: June 04, 2024, 09:39:15 pm »
Did you check for faulty (shorted) PTC's?
This is a common fail after misuse at least in flukes.

Good luck in your repair

J Alonso
 

Offline BENAMORMEDTopic starter

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Re: help about multimeter UNI-T UT58C
« Reply #9 on: June 05, 2024, 08:24:37 pm »
hello

yes it's ok no short
 

Offline BENAMORMEDTopic starter

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Re: help about multimeter UNI-T UT58C
« Reply #10 on: June 05, 2024, 08:59:22 pm »
hello

green point no beep
red point continous beep and fault mesurement
green and red sometimes beep sometimes no beep

can any one help to resolve this problem
 

Offline Poroit

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Re: help about multimeter UNI-T UT58C
« Reply #11 on: June 06, 2024, 08:06:20 am »
How did you test LM358 & CD4011?
Did you review component data sheets & measure signals on the various pins?
 

Offline BENAMORMEDTopic starter

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Re: help about multimeter UNI-T UT58C
« Reply #12 on: June 06, 2024, 01:52:58 pm »
How did you test LM358 & CD4011?
Did you review component data sheets & measure signals on the various pins?


no not yet only the component related to the IC 358 et 4011 (resistance and capacity marked in red) and short test in the Pins

 


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