I know that the schematic is hard to read but can someone please let me know if the op-amp voltages I am getting are correct. This MXR Stereo Chorus is the version with a transformer and a MN3008. Your help would be appreciated. Thanks.
U1: RC4558
pin 1: 6.34
pin 2: 6.34
pin 3: 6.34
pin 4: 0.00
pin 5: 5.87
pin 6: 6.32
pin 7: 6.32
pin 8: 12.12
U2: MC1458
pin 1: 6.35
pin 2: 6.35
pin 3: 6.35
pin 4: 0.00
pin 5: 6.35
pin 6: 6.35
pin 7: 6.35
pin 8: 12.12
U3: RC4558
pin 1: 5.83
pin 2: 5.83
pin 3: 5.83
pin 4: 0.00
pin 5: 5.83
pin 6: 5.83
pin 7: 5.83
pin 8: 12.12
U4: RC4558
pin 1: 2.3
pin 2: 6.34
pin 3: 6.34
pin 4: 0.00
pin 5: 6.34
pin 6: 6.34
pin 7: 11.38
pin 8: 12.12
U5: RC4558
pin 1: 3.4
pin 2: 3.4
pin 3: 3.4
pin 4: 0.00
pin 5: 8.7
pin 6: 8.7
pin 7: 8.7
pin 8: 12.12
(https://i.postimg.cc/zVbHD9QB/mxr-stereochorus-schematic.jpg) (https://postimg.cc/zVbHD9QB)
U4 doesn't look too happy.
When I remove U4 and check the voltages again, the other op-amp voltages are around 6.3 volts. I thought maybe U4 was bad but I replaced it with a new op-amp and it didn't make a difference.
+1 agree with Scruffie. U4 doesn't look happy. If things look better with it out, I'd start hunting for a short or a solder whisker or a bit of muck between two connections on the chip socket or the components around it. One thing that often works for me is to turn the power off and then drag a small flathead screwdriver between the pins that aren't supposed to be connected.
HTH,
Tom
I checked all of the components around U4 and they all look good. I will check for shorts or connections that aren't supposed to be there.
I checked all of the traces and solder joints. I didn't see any unwanted solder bridges or bad traces. I decided to change the dip switch settings and now the pedal is working. Thanks for the help.
Ryan