A Battery Replacement And Maintenance On An Electronic Scale
A restaurant manager brought this scale for repair. He said it works only when the AC line is connected and the display is flickering. It does not charge and when the AC line is disconnected it goes into shut down.
This is the model number and as seen it measures up to 150KG. The customer uses his scale to weight meat and it was urgently needed.
I have worked on this kind of scales before and usually the problem is the main battery; usually it is shorted out causing the display to flicker and of course the charging is not done the way it should be.
It is a heavy duty scale so it is time to open and get it fixed.
When powering on the device it shows the AC light but the display is flicking and I could not get that on camera. It measures fine; it is the charging and the flickering is what was bothering the customer.
Four screws on the back were taken off and I was able to see the inside of this scale.
I measured the voltage going to the battery and it was not steady at all indicating either a shorted battery or bad power supply. The customer supplied a new power supply so I headed directly to that battery and de soldered it off.
The moment these wires were soldered off the battery, the flickering stopped and was showing a normal display.
That is the battery found inside the scale and one of the ways to test it out (other than voltage testing) is shaking the battery and sure enough I heard something rattling inside which is an indicator the battery was dry and needed replacement.
Before replacing the new battery, I checked the main line that goes to the battery and this what I got; Almost 12 DC and that is what needed so soldered the new battery in.( it was a little bit hard to find a replacement but finally found one).
I put everything back together and tested the scaled it was fine. I weight almost 100 kilos so I am ok with that…LOL
Any way I called the customer for pick up and the he was happy that it was repaired that soon.
This article was prepared for you by Waleed Rishmawi, one of our ‘Master Authors’ and currently working in the Bethlehem area of Palestine repairing electrical and electronic equipment.
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Note: You can check his previous article on How To Fix An Electrical Outlet With Surge Protector Built In Repaired