[Heathkit] can't figure the s meter circuit on receive

[wt4t at reagan.com]

                 Working on a HW-12a, Have the receiver up and running somewhat ok now. The meter responds to set grid current,fine,all the meter adjustments work as they should ,but when back in receive mode the s meter is dead. Looking at the schematic I just don't see how the s meter drops out on receive. other than the R-93 to the first rf amp .just don't see where to go. Any one explain the s-meter and circuit to me .
thanks for any help
73
dale wt4t