Sound Skulptor forums

Build help and troubleshooting => MC624 Monitor Controller => Topic started by: mcdavis on October 26, 2024, 02:06:54 AM

Title: high offset on u2/u5
Post by: mcdavis on October 26, 2024, 02:06:54 AM

the other two opamps zero'd fine, u2 shows around 14.8mv and u5 shows about 12.2mv without any more travel on the pot.

What should I look at?

also input 3 and 4 buttons, when one is pressed both LED's light up, but I can hear relays activating for each one individually. I don't actually care that much about the light assuming it works right.

Any input would be great.

Title: Re: high offset on u2/u5
Post by: JPK on October 26, 2024, 04:38:42 PM

u2 shows around 14.8mv and u5 shows about 12.2mv
This may be the meter cable causing the IC's to oscillate. Try metering on TP6 (instead of TP2) and TP8 (instead of TP4) with the volume maxed.

also input 3 and 4 buttons, when one is pressed both LED's light up
You must have a short somewhere on U14 between pin5 and pin6. It can also be on connectors CN34a / CN34b (last 2 pins on the right)

Title: Re: high offset on u2/u5
Post by: mcdavis on October 26, 2024, 06:40:42 PM

I think you were right about the offset, I checked later and everything seemed fine and I was able to zero them out.

I still check for shorts on the IC/pins thank you!