Author Topic: Trying to repair a Bosh PPW3120/01 Weight Scale  (Read 2285 times)

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Offline ChrisGreece52

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Trying to repair a Bosh PPW3120/01 Weight Scale
« on: August 25, 2014, 03:08:19 pm »
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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« Last Edit: August 25, 2014, 03:28:55 pm by ChrisGreece52 »
 

Offline mij59

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Re: Trying to repair a Bosh PPW3120/01 Weight Scale
« Reply #1 on: August 25, 2014, 04:38:32 pm »
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.
 

Offline ChrisGreece52

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Re: Trying to repair a Bosh PPW3120/01 Weight Scale
« Reply #2 on: August 25, 2014, 04:59:44 pm »
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
 

Offline German_EE

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Re: Trying to repair a Bosh PPW3120/01 Weight Scale
« Reply #3 on: August 25, 2014, 05:15:51 pm »
Make sure that the battery contacts are nice and clean. Scales like this are often used in bathrooms and the dampness tarnishes the contacts.
Should you find yourself in a chronically leaking boat, energy devoted to changing vessels is likely to be more productive than energy devoted to patching leaks.

Warren Buffett
 

Offline ChrisGreece52

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Re: Trying to repair a Bosh PPW3120/01 Weight Scale
« Reply #4 on: August 25, 2014, 05:21:59 pm »
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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Offline mij59

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Re: Trying to repair a Bosh PPW3120/01 Weight Scale
« Reply #5 on: August 25, 2014, 05:59:11 pm »
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.
 

Offline ChrisGreece52

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Re: Trying to repair a Bosh PPW3120/01 Weight Scale
« Reply #6 on: August 26, 2014, 02:57:50 pm »
Mij59 i have to tell you a huge thanks :D.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 :P
 


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