Ir sensor wont detect bed

  • Well, I tried to print something but the print totally failed. Switched from Slic3r to Simplify3d. Test print came out ok but my large scale print failed causing the print to break the IR sensor of hot end mount. Mount is designed to break away to prevent damage to the board. Remounted IR sensor, when powered on it flashes 4 times like normal but will not detect anything underneath sensor. What could be wrong? Only had it for 4 months and always worked great. Have a new one on order but if something I could fix to get back up and running sooner. Thanks for any ideas.

  • administrators

    Is it the older sort with through-hole IR LEDS and photodiode, or the newer sort with SMD components?

    If it is the older sort, the IR components have probably been bent out of alignment. If it's the newer sort, one of the joints between the IR components and the PCB may have detached.

  • It is the newer version with surface mount ir components. I reflowed Solder as D2 was not making contact. But I found the resistor to D1 labeled 1001 (circled in Red) was pulling down to 22 mv from 768 mv compared to D2's (Circled in Blue) 78 mv pulled down to 468 mv. Am I right in thinking I need to replace that one resistor?Sorry I Couldnt figure out how to post an image so here is a link.!AvWJUI3FBcOruQTkl51MNKfi2eK8

  • administrators

    If you are using an oscilloscope to look at the signals, you should see the end of each of those resistors that is connected to the microcontroller switch between 0V and nearly 3.3V, and the end connected to the diode switch between 0V and about 1.2V.

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