[Amps] ACOM 1500 1ATR4B errors

[wa3afs at nycap.rr.com]

My two and half year old ACOM 1500 started dropping back to standby mode with the 1ATR4B error 
(related to the vacumn tr relay) which became more and more often. 
I have placed the amp into an envelope (large) and it is now waiting for repair at HRO in Virginia. 
I have been driving the amp with the ICOM 7610 (delay default at 10ms, no buffer interface) for the 
past 11 months (before that was the ICOM 7600) and have the PALSTAR HF-AUTO tuner following 
the amp. 
My question for when I receive the repaired amp back is there anything (settings, etc) that would 
lessen my chances of this happening again? 
I generally run the ACOM 1500 at 900 watts or less (learned my lesson by blowing up a capacitor in 
the LDG-1000 Pro and killing an Ameritron remote antenna switch) . 160m through 6m SSB, CW, 
FT8, RTTY) 
73 
Bruce, WA3AFS

   AEC, Albany County 
    ASEC, Eastern NY 
    SKYWARN Regional Coordinator, NWS, Albany, NY
     Net Manager, ENY ARES/RACES Section Net