[Amps] Command HF 1250

[Hugh Phillips K7XM]

I have a Command HF 1250.

I'm trying to locate D21.

(1) When Keying the amp I see high Grid Current.
(2) F2, 1 amp fuse on control board OPENS.
(3) I see slight NEGATIVE plate current.
(4) I think D21 is shorted.
(5) Where is D21 located???
This isn't the easiest amp I've worked on.
I can't understand why they didn't high more components inside more enclosures.

Thanks In Advance.
73,
Hugh
K7XM