[Yaesu] FT1000MP Mk V constant high SWR

[Martin Sole]

Hi,

I have an FT1000MP Mk V on the bench here with an odd problem.

ATU off
Ant 1 or 2, no difference

Max power in RTTY or FM with MOX approx 50 watts and SWR showing between 
2 and 3 to 1, bouncing around a bit.

Good solid 50 ohm load on the ant connector and confirmed correct choice.

I see the fwd/rfl coupler on the LPF module and the output is an RCA 
connector that goes to the ANT jack of the tuner main unit. Through a 2 
pole relay to select tuner in or out and then a U15J tx PIN diode and 
from there to the 2 relays that select ant A or B.

Pulling the RCA at the tuner main and sending this directly to a dummy 
load power meter shows 200 watts and 1:1 confirming the problem is on 
the tuner main board.

My guess is D6452 the U15J PIN diode. Are these a known failure item? 
How is availability, options?

Martin, HS0ZED