Digital Section not working

[kom]

Hello,

I just completed my X0Xb0x but unfortunately it does not work. There is just a humming sound on the headphone. No LEDs light up, no reaction on turning/pressing switches. So far, I found out that there is only 1.29 Volts on pin 40 on the cpu. when I disconnect J3 from the mainboard there is 5Volts on PIN 3 and 4 of J3. Voltage on J4 is correct, even if J3 is connected to mainboard.

Any suggestions are appreciated.

Thanks
kom

[MMM]

If the CPU is socketed please remove it and measure again the voltage between the appropriate points of the socket (pin 40 and pin 20).

[kom]

Hi MMM,

thanks for your reply.
After spending two hours of investigating the issue, I found out that I put in IC6 resp. the corresponding IC socket backwards. Just turned IC6 around and now it works as expected. I also had an issue with white noise which was caused by a cold solder joint on a transistor. Now my xoxbox produces the sound we all love and I am very happy with it.

Best regards,
kom

[MMM]

Good to hear that things are working now. Have a lot of fun with your xoxbox!