On Thu, 16 Jul 2020 06:45:11 -0700, abrsvc wrote:

Without the schematic, based upon the symptoms described:

1) The "delay" portion is working as expected 2) The delayed signal
amplitude is smaller than expected. This would suggest that there is
likely an op-amp down stream that is not working correctly or at all.
Look for a TC072 or perhaps a 4558 IC that is faulty post the MN chips.

Dan

Or high ESR coupling cap?