smr-4 power suply test fail 5.64V -4.94V 0.1V
  • I am in Step 4 of the SMR-4 assembling. The test is OK but all the blue points are at 0.01V, all the red points at 5.64V, and all the green points at -4.94V.
    I am using a 9V power suply.

    It is OK to have 5.64V? Can I continue soldering?
  • No, you’re going to damage the MCU if you do that! It looks like the 7805 is not operating properly. What is the voltage you get straight out of the power supply?

  • 12.12V
  • Supply voltage is high enough, OK.

    It looks like the 7805 is damaged. I found in the forum that someone had the same problem and solved it by replacing the 7805.

  • OK. I'll try to find a 7805 in a store here!. (I live in a little town of Spain).
    Thanks for the help.
  • I just got this from a friend.

    SGS 6438P

    Do you think it would be compatible?
    I can just try it and see...
  • Looks good.

  • I put the new 7805 and now it works ok. -4.93V 4.99V 0.01V.
    Thanks for the help!