Suitable replacement components

Discussion in 'The Projects Forum' started by tcawley29, Mar 8, 2013.

  1. tcawley29

    Thread Starter Member

    Jan 23, 2013
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    Hi,
    I have two components that are dead on my treadmill controller board. TVS2 and Q8 are the dead components and Q8 didn't have a part number on it. TVS2 had a very blurry part number on it which may have been something like: NPL135 OFL135. I'm not sure as it was hard to read. Looking at the attached diagram could anyone please recommend replacement parts for me, or even better yet, maybe provide a link to the parts on ebay.
    TVS2 looked like an In rush current limiter and Q8 looked like a transistor.
    Thanks
    Tommy
     
  2. praondevou

    AAC Fanatic!

    Jul 9, 2011
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    Please post a photo of the two components and the PCB they come from.
    Is "TVS2" printed on the PCB? Would be a strange place to put in a TVS.

    R114 doesn't make sense either. Is that supposed to be 4.1kΩ?
     
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  3. tcawley29

    Thread Starter Member

    Jan 23, 2013
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    Yes R114 is called a 5W 4.1KMT.

    Here is TVS2
     
  4. tcawley29

    Thread Starter Member

    Jan 23, 2013
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    Here is Q8 - The transistor. The diode beside it is fine
     
  5. tcawley29

    Thread Starter Member

    Jan 23, 2013
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    Here is the entire front of the board
     
  6. praondevou

    AAC Fanatic!

    Jul 9, 2011
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    This is an NTC. It serves as an Inrush current limiter. Check you diagram again, I would say it is mounted across the relay contact.

    Someone has to look up the correct value.

    Is there no marking left on the transistor?
     
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  7. tcawley29

    Thread Starter Member

    Jan 23, 2013
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    Yes the TSV is mounted across a relay pin. Its not my diagram. Its one someone found on the web which is ment to be like my board, which it seems to be.
    I have no idea how to find its value.
    Nope. The writing on most of the components must have been wiped off.
    I just wish I knew what to replace them with so that I could use my treadmill again
     
  8. praondevou

    AAC Fanatic!

    Jul 9, 2011
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    Just saw, you already had another thread about the same problem. There are other components burned, apparently.
    You will have to draw the schematic by yourself.
     
  9. tcawley29

    Thread Starter Member

    Jan 23, 2013
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    Was just the TSV and the Transistor that were burned. I also replaced a diode which had shorted out.
    I wouldn't be able to draw one of these diagrams in 100 years unfortunately as I havn't a clue about them.
    Thanks
     
  10. praondevou

    AAC Fanatic!

    Jul 9, 2011
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    IF this schematic is about correct then Q8 is probably a n-FET, since the common pinout is GDS (gate, drain, source).

    That's why they maybe put it in the minus return path, so they can use the minus as reference.

    You could try something like this: http://www.vishay.com/docs/91054/91054.pdf

    But it seems yours is fully isolated, so either use a isolating pad or a Fullpak.

    See the attached picture , there are a lot of parts on digikey.

    Search for :
    MOSFET

    Then filter for:
    through hole
    max voltage 400V upwards
    maximum drain current: 7A upwards
    TO220 FP or Fullpak
     
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  11. tcawley29

    Thread Starter Member

    Jan 23, 2013
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    Thanks a million. Please God it works out :)
    Tommy
     
  12. tcawley29

    Thread Starter Member

    Jan 23, 2013
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    Okay, so I got the mosfet/transistor you recommended and installed it. The treadmill is still a no go. I measured the output power of the main transformer where it meets the board. It is supplying 236 volts ac. I then measured the dc voltage across the bridge rectification with four diodes and was only getting a reading of around 3.3-3.7 volts. I could be wrong here but shouldn't that be a much higher value. Please help as I feel I am so close to having this working. Here is the wiring diagram another member supplied.
    Thanks,
    Thomas
     
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