What was found
DURING PREFLIGHT, DISPLAY UNITS 2,4 AND 5 INTERMITTENTLY WENT BLANK. DOWN POWERED ACFT FOR 10 MINS, POWERED ACFT. PERFORMED RTS ON ALL 3 VIA'S ALL TEST PASSED IAW MM 31-43-01-5. TSI ADDED TO REPLACED NR 1 VIA AND PERFORM ADJUSTMENT TEST ON ALL DU SWITCHING.