Surround Sound Decoder with Digital Delay (May 1999):
There are a few minor misprints in the schematics for this project: C31 should be a 6.8nF, not 6.8uF as shown, R9 is 10M, not 1M, and pin numbers 1 and 15 of IC4 are transposed -- output Q5 is really pin 1, and reset is pin 15. The parts list and overlay are correct.
There are also two resistors shown as R37 on the schematics -- The one that connects to the junction of D8 and D23 should be R38, as shown in the overlay diagram and parts list.
Finally, The parts list shows D5 as a 1N4148 signal diode. This should be a 1N4004 as shown on the schematic and overlay diagrams, although a 1N4148 will actually work just as well in this situation.