Trying to repair a Bosh PPW3120/01 Weight Scale

[ChrisGreece52]

Hello guys.As weird as it sounds i am trying to repair a weight scale.
The problem:
The scale usually turns on when pressure is being applied to its 4 legs.
But when i apply pressure it wont show anything on the little lcd.
I tried to change the 2 CR2032 batteries with no result.
The repair process so far :

• I am just a beginner.I just play with circuit boards i have not studied on electronics yet and my  experience does not cover the repair section of electronics.

The cons of the repair :

• The main processor is covered by this black thingy (pictures bellow)
  New at repairs
  

The pros of the repair:

• My house needs a weight scale and this is about 60 USD new (40 euro)

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[mij59]

Hi,

Maybe the scale powers on by actuating a switch, the switch could be faulty.
Check for mechanical issues, lose wire etc.
Got a multimeter ?
Post some photo's of interior of the scale.

[ChrisGreece52]

Ill check the switches and since i dont have a multimeter to use the continuity test function ill have to see if the switch lights an led up ...
As for the wires ill remove the metal plate and then check just to be sure there is no damaged wires beneath it.
Also photos will be up soon

[German_EE]

Make sure that the battery contacts are nice and clean. Scales like this are often used in bathrooms and the dampness tarnishes the contacts.

[ChrisGreece52]

Checked the battery contacts nothing there the looked like brand new i also tried scraping the metal with tweezers just to be sure it would make good contact.
Also no loose / cut or damaged wires that i can see of.
The switches on the other hand seem a bit complex... they are not your regular tactile button switch anatomy i have some pictures bellow.
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[mij59]

Checked the battery contacts nothing there the looked like brand new i also tried scraping the metal with tweezers just to be sure it would make good contact.
Also no loose / cut or damaged wires that i can see of.
The switches on the other hand seem a bit complex... they are not your regular tactile button switch anatomy i have some pictures bellow.
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On the white part of the foot is a metal ring, it could be part of the switch.
Check the board on the right of the main board seems to be some gunk on it, also check the switch on the board.

[ChrisGreece52]

Mij59 i have to tell you a huge thanks .Not only you but all the guys here helped me a bunch.
The problem was at the main board where you noticed the gunk on there.That may was a broken solder connection i tried reflowing the solder using a bit of flux then cleaning the board using an alcohol pad.
So thanks to everyone here for your help.
Time to learn my weight now