I replace the PS FETS,amp powers up and play good audio.
With no speaker connected i see 1.132mv on the output terminal.With
speaker connected it goes away.Wondering if that is normal for this amp.
The output section has no work done in it.
D14 connects between the Primary ground and the RCA ground. If this was open and causing the DC offset, the offset should have gone away when you connected a properly grounded signal source.
If this amp is not yours, tell the owner that the diode was likely burned when 12v contacted the RCA shields. This could have damaged the shield ground in the head unit as well.