Mates bread maker stopped working so I had a look inside and saw this burned resistor.

I’m guessing the heat changed the colors a bit so wondering if anyone has experience in reading cooked resistor values.

I removed it from the PCB and measured it at 403 Ohms.

Thanks for any help.

  • Saigonauticon@voltage.vn
    link
    fedilink
    English
    arrow-up
    0
    ·
    1 year ago

    Well, arguably keeping the resistor the same value would result in a somewhat known state, and changing it would put it in an unknown state. The unknown state could be better or worse. I can’t see enough to know what the circuit does to say.

    What you could do instead, is set the resistor to the same value, but rated for higher thermal dissipation. Then measure how hot it gets to identify if the real problem is somewhere else. Another part might burn/explode instead though, so I’d consider carefully how to proceed, and probably wear goggles + have a fire extinguisher in the room.

    My main concern is by ‘fixing’ it with a resistor with higher thermal dissipation, I’ve created a fire hazard because that dissipated heat now has to ‘go somewhere’, which may be the plastic case. A thermal camera is handy to see if some part of the board gets unacceptably hot during normal operation.

    • WaltzingKea@lemmy.nzOP
      link
      fedilink
      English
      arrow-up
      0
      ·
      1 year ago

      The case is basically fully metal, just a bit of plastic inside for mounting the PCB to and a few other bits of plastic outside. Plus there is a temperature fuse in the case also.

      From the resistor size (11.5 x 4.5mm) I think it would have been a 2W resistor when comparing to sizes on Digikey. I made a 500 Ohm 2W resistor from 8 1/4W 1K resistors then put a larger resistor in parallel to that to bring it down, measured it to 489 Ohms.

      I’m going to run it a few times then open it up again to see if there is any new damage to the board before returning it.