PCB for a wine fridge

Discussion in 'General Electronics Chat' started by lowbo69, Mar 16, 2013.

  1. lowbo69

    Thread Starter New Member

    Mar 16, 2013
    1
    0
    Hi Folks,
    I've recently purchased a 2nd hand wine fridge on the premiss I can get it working again!
    It was not cooling properly and is a thermoelectric cooling system.
    On investigation it seemed the rear pcb was not powering any fans or the thermo plate. When turned on the fans started up then stopped.
    So I picked up a new pcb from the manufacturers hoping this would do the trick.
    I also purchased a new cooling plate to ensure a colder fridge.
    When set up the rear fans did not work. unplugging the thermo plate allows the rear fans to work. On the board the red power light dims once all 3 fans are plugged into the board. When the thermoplate is attached the rear fans stop working? Seems to be lack of power through the board?
    Being inquisitive I put in place the old board again to see what happened when plugged in. Again the same issues were present on this board even though I assumed it was dead. The red power light comes on and the green (ground??) light is on until any peripherals are attached. This is the case with the new board as well? Now i'm unsure as to whether both boards are faulty or something else is going on, as I'm a novice with electronics I'm baffled.

    I have swapped the internal thermostat switch and light pcb for another one I have on another fridge, which is exactly the same model and working fine.
    This made no difference to the board functioning.

    I have left the fridge in situ with all components plugged in hoping the rear fans kick in at a certain temp to cool the heatsink, but the fridge went a few degrees colder and that was it. It should be in the range of 16-19° but sits at 25. The thermo plate is on the correct way so not the issue.

    The board consists of power socket, earth goes to the fridge body, sockets for 3 fans, heatsink connection thermoplate connection and connection for internal thermostat and light.
    Please see attached pic. This is the old board and so I've attached spade connectors to allow me to test it again. The new board is exactly the same layout but includes male spade connectors for the thermoplate.

    Any assistance would be welcome as I'm totally stumped and the only other thing I could do is remove the board from the working fridge and test it with the connections on the non working fridge, but I'm not sure I want to pull apart a working fridge:)

    Hope this explanation isn't too confusing!!

    Look forward to any ideas.
     
  2. KJ6EAD

    Senior Member

    Apr 30, 2011
    1,425
    363
    If the fans don't spin freely (unpowered) when flicked with a finger or small probe, they will draw too much current and cause the power supply to shut down.
     
  3. nigelwright7557

    Senior Member

    May 10, 2008
    487
    71
    If it is of any age then fans wear out and electrolytics dry out.
     
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