Voltage issues (smr4mkii)

filter board is fully assembled, and i’m about to attach the lcd screen on the control board, which is when i tested the boards together. as far as i could tell, the shruthi did not ‘turn on’–no led’s lit up. thinking it might’ve been the power supply i purchased (9v), i used the voltmeter to test it, and got a reading of 13.5V. (elsewhere on the forum, users have stated the only effect of using a higher-voltage power supply is heated voltage regulators.) lastly, when testing the filter board’s voltage (at the points recommended at step 5, “power supply testing”), i got readings of -0.6v at the red points and -3.6v at the green points. lastly, on the control board, i followed the pictures not the instructions, and soldered the ICs directly to the board, without the sockets.

i’ve triple-checked the boards…the solder looks fine. why won’t it turn on? and why am i getting strange readings, that are both negative?

thanks folks

Maybe you switched the voltage regulators?

Is your power supply center pin positive?

sorry for the delayed response. voltage reg’s are okay, and yes the power supply is center-positive. i assume the led’s wont light due to a break in the circuit somewhere…just wondering if there’s anyway of testing the board(s) before the gruelling process of solder-sucking both boards. any and all ideas are welcome. thanks

Could you post a picture of your filterboard? Both sides?