wellhise wh-890d multimeter problem

Thread Starter

exelancehero

Joined Aug 24, 2020
5
Hello i have a wellhise wh-890d multimeter. Yesterday i was trying to charge a motorbike 12v battery i unplugged the charger to check voltage then i checked the amp it is taking then i forgot the probe was in the amp hole (left 20A hole on the photo) then i put the meter on voltage mode and i tried to check the voltage but because it was on amp hole i shorted the battery and i saw a spark, i thought the fuse was blown tried the modes on the meter. Now i can't measure dc voltage (it outranges at 200mv mode and shows 0.003-0.004 on 12v), can't measure resistance (it doesn't show any resistance even if i short the probes), can't measure capacitance (stays at zero), can measure ac voltage correctly, continuity mode doesn't work , ncv mode works. i opened it up (photos are below) as you can see on the other side of the board there's a ripped trace that was a small strip of metal that was blown like a fuse i tried to solder a thin piece of cable but when i turned the slider it ripped it off. And there was a very bad burnt smell from the board (probably the fuse thing).20210119_150544.jpg20210119_150712.jpg20210119_150717.jpg20210119_151023.jpg20210119_150722.jpg Any luck of fixing it ?
 

twohats

Joined Oct 28, 2015
206
Looking at your good pictures, bottom right, RX area it states F2, so that's a fuse.
Can you check it out?
Good luck..
 

rsjsouza

Joined Apr 21, 2014
318
In your fourth photo, the thick track at the bottom left is completely vapourized - it did a good job to protect the fusistor F2. :rolleyes:

I am surprised that your meter can't measure anything on V/ohm input but, given that a lot of energy went through the A input, that may have elevated the voltage high enough to damage the main IC. Unfortunately these meters do not usually have good input protection, thus anything can happen.

Good luck!
 

Thread Starter

exelancehero

Joined Aug 24, 2020
5
In your fourth photo, the thick track at the bottom left is completely vapourized - it did a good job to protect the fusistor F2. :rolleyes:

I am surprised that your meter can't measure anything on V/ohm input but, given that a lot of energy went through the A input, that may have elevated the voltage high enough to damage the main IC. Unfortunately these meters do not usually have good input protection, thus anything can happen.

Good luck!
Actually the track was blown but not ripped. I ripped it on accident :D. So you are saying that ic is dead probably. And i don't know how in the hell am i supposed to change that "black blob" type ics :p. So no luck on this meter then. Thanks for your help.
 

Thread Starter

exelancehero

Joined Aug 24, 2020
5
In your fourth photo, the thick track at the bottom left is completely vapourized - it did a good job to protect the fusistor F2. :rolleyes:

I am surprised that your meter can't measure anything on V/ohm input but, given that a lot of energy went through the A input, that may have elevated the voltage high enough to damage the main IC. Unfortunately these meters do not usually have good input protection, thus anything can happen.

Good luck!
Also it is very strange that it can only measure ac voltages. It has the blown track that was supposed to protect the ic, the fusistor, and that 2 diodes seen on the second photo next to the black lead. Weren't they enough to protect from this kind of abuse ?
 
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