Repair thermoelectric cooler

Discussion in 'Technical Repair' started by wayneh, Sep 23, 2014.

  1. sacha

    New Member

    Apr 25, 2017
    1
    1
    Many thanks for the detailed info, I fixed it!

    Mine shows the sympton of rapid blinking red led, and out of the two fan, one attempted to but could not start ( fan turns a little bit every other second), the other just have a busted bearing and would not turn. The two 200v capacitors are blown, juice running out here and there.

    Replaced all caps, replaced the two fans to one larger fan that was held on with tape, and it seems to work!

    Thanks again for sharing the info!
     
    wayneh likes this.
  2. MaCheFai

    New Member

    May 10, 2017
    11
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    Have a link?
     
  3. MaCheFai

    New Member

    May 10, 2017
    11
    1
    IMG_0281.JPG IMG_0282.JPG I have the fx-101 in a 4 fan wine enthusiast cooler with 2 boards. One side is fine, the other does not power the fans to cool. I tested the dead fans on the other board and they work fine. I tested the running fans on the bad board and they do not run. The board also has both the red and green lights fully active with no other apparent signs of failure.

    Any thoughts on how to get it back up and running?

    Also, is the fx-102 a direct replacement for the 101? They look a bit different. I found this and for the price, would get, but am worried it's not the correct replacement. http://www.yoycart.com/Product/521741561824/

    And here's a pic of my board:
     
  4. wayneh

    Thread Starter Expert

    Sep 9, 2010
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    Ummm... maybe replace the capacitors like everyone else?
    I can't answer that. My hunch is that yes, it can replace FX-101 but it's only a hunch.
     
  5. MaCheFai

    New Member

    May 10, 2017
    11
    1
    Thanks for the reply! The only reason I hesitated replacing all of the capacitors was because both lights on the board are solid, the front temperature gauge is working as well as is the light inside the refrigerator. It just seems to be isolated to the fans with no error codes? :/
     
  6. N11778

    Member

    Dec 4, 2015
    98
    27
    Here is a diagram that's close to the cooler i have.
    I got it off this site someplace can't remember where. Will post the diagram.
    looks like it should be easy to trouble shoot the fans using them for hints.
     
  7. wayneh

    Thread Starter Expert

    Sep 9, 2010
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    Any idea if your peltier units are working? Just curious - either way the shotgun approach of re-capping is still the only approach unless you can do board level diagnostics. I can't. If you have an oscilloscope and some experience with SMPS, you might have a chance.
     
  8. MaCheFai

    New Member

    May 10, 2017
    11
    1
    Don't believe so, but I cut the board out last night to replace the caps. So can't check until I get it back in.
     
  9. MaCheFai

    New Member

    May 10, 2017
    11
    1
    Replaced all of the caps, plugged it all back in and have both lights lit again, but no fans....beyond frustrated.

    Any other advice for trying to track my issue down?
     
  10. N11778

    Member

    Dec 4, 2015
    98
    27
    Did you look at post 86 the diagram it should be close to your board.
    and Is it cooling but the fans not running.
    check that out.
     
  11. MaCheFai

    New Member

    May 10, 2017
    11
    1
    Thanks for the reply. Unfortunately, reading those schematics is above my pay grade. I tried, but am not even sure where to begin with them.

    And no, it is not cooling either. Seems the peltiers and fans have no power. I know the fans work as I can hook them into the other board and they run fine. But when I hook up the running fans into this board, they do not run either.

    Any help is so very much appreciated!
     
  12. wayneh

    Thread Starter Expert

    Sep 9, 2010
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    That's frustrating for sure but we knew going in that this was possible. If you're weak on reading schematics and don't have test equipment, I can't recommend continuing unless you just want to for the challenge of it. I wish I could recommend something to try but I don't have the chops.

    Well maybe there's one thing. There may be a few larger transistors on heat sinks on the PCB. One of them might be dead. You could try removing and testing them. Or probing the voltages on their pins while it's powered.
     
  13. N11778

    Member

    Dec 4, 2015
    98
    27
    Yes one or both of the transistors could be bad mine went bad when the capacitors went bad. I replaced them with PHD13005 Transistors
     
    Last edited: May 18, 2017
  14. MaCheFai

    New Member

    May 10, 2017
    11
    1
  15. wayneh

    Thread Starter Expert

    Sep 9, 2010
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    Yes. The lights show that they have power. So some things on the board are working. It could be very little but you could extrapolate and say the 'low power' part of the circuit is working. But the power transistors that control the larger loads such as the fans and peltier are the last step that connects the small control signals on the PCB to the power source to drive those loads.

    Transistors aren't too hard to test but if you want to just go ahead and replace them, I'd read the part numbers first. There are probably many substitutes that will work – it's a poor design that depends on the unique properties of a transistor – but it's good to know the specs of the original part. Type (N versus P, BJT versus MOSFET), max working voltage and current rating are the main specs to start with.
     
  16. MaCheFai

    New Member

    May 10, 2017
    11
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  17. MaCheFai

    New Member

    May 10, 2017
    11
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    So I was finally able to track down the culprit! I had to take a couple of deep breaths and approach this problem from a new angle. I figured since the lights were solid, the issue had to be south of the lights and before the plugs to the fan. And since I'd already replaced all of the caps, it could likely only be one other thing, the damn fuse that's covered in heat shrink. So I peeled away the wrap and sure enough, it was fried. So I soldered a temp bridge, and viola, fans kicked on and peltiers got cold! I knew I shoulda checked that fuse early on, but since everyone had success with the cap replacement, I headed down that path and forgot about checking the fuse.

    Anyway, for those who have that second fuse, it's worth a quick check before replacing caps. Either way though, really appreciate everyone's help, I've learned a lot!
     
    wayneh likes this.
  18. N11778

    Member

    Dec 4, 2015
    98
    27
    you did not wast your time changing the caps, they are what blew the fuse.
    Mine blew the fuse too, but the bad caps toasted the transistor first then the fuse blew.
    anyway good job hanging in there.
     
    MaCheFai likes this.
  19. wayneh

    Thread Starter Expert

    Sep 9, 2010
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    Agreed. I think my fuse might have blown also. Can't recall.
    Anyway, nice job. It's not an expensive board but you feel like a million bucks when you fix one.
     
    MaCheFai likes this.
  20. MaCheFai

    New Member

    May 10, 2017
    11
    1
    Hey guys, one last question. Should I replace this fuse with a slow or fast blow fuse? I never knew there was a difference, but when trying to track down this fuse, I'm having a tough time. Anyone had luck finding it online? It's 5a 250v with leads
     
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