+ Post New Thread
Results 1 to 4 of 4
  1. #1
    Newbie level 2
    Points: 20, Level: 1

    Join Date
    Jun 2019
    Posts
    2
    Helped
    0 / 0
    Points
    20
    Level
    1

    Failed MOSFET in switch mode power supply for an audio mixer

    Hi

    I have a failed MDF4N65B 4 amp mosfet in a SMPS powering a Mackie ProFX12 v2 audio mixer that seemed to fail when there was a power cut even though the SMPS looks like it has more than adequate mains spike protection and no other damaged components that I can tell/see, all caps look good but will test before new mosfet install, however I suspect the device is under rated for it's purpose.

    My question is: Should I use the same 4 amp mosfet and adapt better cooling or upgrade it if possible with the MDF7N65B which is a 7 amp device?

    If the 7 amp mosfet could be used as an upgrade would the running temperature of the 7 amp mosfet be lower than the 4 amp mosfet? The reason I ask is that the mixer has to work in higher temperatures than normal here in Spain so it would benefit from a lower temperature device.

    From the specs of the 7 amp mosfet it looks very similar apart from the turn on and turn off times or am I missing the bigger picture here?

    I would appreciate any help and thank you in advance!

    Please see attached PDF's

    •   AltAdvertisement

        
       

  2. #2
    Advanced Member level 1
    Points: 2,659, Level: 12

    Join Date
    Aug 2016
    Posts
    470
    Helped
    72 / 72
    Points
    2,659
    Level
    12

    Re: Failed MOSFET in switch mode power supply for an audio mixer

    Hi,

    The information provided is so little. Please tell us more about the SMPS and also how it was selected for powering the mixer.

    It seems like it was bought off the shelf. In order to provide adequate information easily I would say you should post links to documentations for both the SMPS and the mixer.
    -------------
    --Akanimo.


    1 members found this post helpful.

    •   AltAdvertisement

        
       

  3. #3
    Newbie level 2
    Points: 20, Level: 1

    Join Date
    Jun 2019
    Posts
    2
    Helped
    0 / 0
    Points
    20
    Level
    1

    Re: Failed MOSFET in switch mode power supply for an audio mixer

    Quote Originally Posted by Akanimo View Post
    Hi,

    The information provided is so little. Please tell us more about the SMPS and also how it was selected for powering the mixer.

    It seems like it was bought off the shelf. In order to provide adequate information easily I would say you should post links to documentations for both the SMPS and the mixer.
    Hi Akanimo
    Yes it was is a Mackie ProFXv2 Mixer

    Please find pictures of the unit plus power supply removed from unit.Click image for larger version. 

Name:	ProFX12v2 MOSFET side.JPG 
Views:	6 
Size:	44.6 KB 
ID:	153987Click image for larger version. 

Name:	ProFX12v2 PCB side.JPG 
Views:	4 
Size:	133.1 KB 
ID:	153988Click image for larger version. 

Name:	ProFX12v2 Top side.JPG 
Views:	5 
Size:	112.8 KB 
ID:	153989Click image for larger version. 

Name:	ProFXv2 gut shot.jpg 
Views:	2 
Size:	468.2 KB 
ID:	153990Click image for larger version. 

Name:	ProFXv2 Front shot.jpg 
Views:	2 
Size:	453.4 KB 
ID:	153991



    •   AltAdvertisement

        
       

  4. #4
    Advanced Member level 5
    Points: 10,038, Level: 23

    Join Date
    Aug 2015
    Posts
    1,638
    Helped
    593 / 593
    Points
    10,038
    Level
    23

    Re: Failed MOSFET in switch mode power supply for an audio mixer

    more heatsinking - or a fan ( perhaps small internal one ) are good ideas ....



--[[ ]]--