M3900 Multimeter Malfunction, can it be fixed?

[csom]

Hi all,
A digital multi-meter (model - M3900, made by Mastech, bought last year ) is behaving in a strange manner. The display is not instantaneous like my other cheap one. It's showing a slow and gradual display of the reading.

For example, suppose I am taking a measurement of 12V AC, it is showing like 8....9....10....11.....12
and when I remove the probes, its going down like 11,10,9....0
And it's taking a considerable amount of time unlike my other one.

Can it be fixed?

Any help will be really helpful!
Thanks in advance.

 

[Mooly]

Probably not worth or possible to fix at component level. If you are 100% sure the meter has not suffered spillage or some other accidental amage then I would remove the batteries and place (press) tinfoil over the whole PCB to remove any residual charge that may be holding some logic in a confused state.

If thats not an immediate fix then repeat leaving the foil in place but also leave it in a hot place for 48 hours and retest.

Other than that its probably pancaked 😀

 

[csom]

Thank you sir 🙂)
I will clean the PCB with thinner and then do as per your suggestion and of course report you back. 🙂
I guess time to gift myself a new meter. 😀
Could you kindly recommend a model that can measure capacitance too or that can be suitable for me in my hobbyist's situation? 🙂

 

[Mooly]

I wouldn't use any chemicals on it unless the PCB is contaminated.

Haven't bought a meter in years so wouldn't know off hand what to recommend. Always worth buying a good one though.

 

[csom]

Just finished cleaning and dried.
Then double checked the existing tinfoil.
Latency lowered now.
But still the problem is there.
So ...... time to go shopping. 😀

Thank you so much Mooly for you always extending helping hand. 🙂))

 

[Mooly]

Your welcome. Good luck with the meter shopping 🙂

 

[Elvee]

Hi all,
A digital multi-meter (model - M3900, made by Mastech, bought last year ) is behaving in a strange manner. The display is not instantaneous like my other cheap one. It's showing a slow and gradual display of the reading.

For example, suppose I am taking a measurement of 12V AC, it is showing like 8....9....10....11.....12
and when I remove the probes, its going down like 11,10,9....0

Probably a relatively minor (but difficult to locate) problem: bad contact, split PCB track, fractured PTH, etc.
Could also be a blown fuse: sometimes, they leave a slightly conductive metal spray.
Check the main function switch, input connectors, etc: anything mechanical

 

[csom]

Thank you so much Elvee.
I re-soldered what I could earlier. Inspected the PCB carefully.
I will do it again in the daylight and post my success or failure. 🙂