What was found
AFTER PUSHBACK R IRS ALIGN EICAS AND DISCRETE LIGHT ILLUMINATED. PERFORMED QUICK ALIGN AND STATUS DID NOT CHANGE. AIIRCRAFT RETURNED TO GATE. MAINTENANCE GROUNDED AIRCRAFT. TRIED NEW CENTER IRU, NO HELP. WAPPED RIGHT & CENTER SYMBOL GENERATOR, NO HELP. ALL UNITS BACK TO ORIGINAL POSITIONS. REPLACED RIGHT IRS INST. SOURCE SELECT SWITCH, S12, PER B SWPM 20-84-15, REMOVED AND REPLACED RELAY K510 (ADIRU SELECT R) AND RELAY K137 ( IRS DC PWR DISCONNECT) NO FIX. REMOVED AND REPLACED IRMP IAW AMM 34-21-02 OPS CHECK GOOD. REMOVED AND REPLACED R IRU IAW B 767 AMM 34-21-01 OPS CHECK GOOD THIS CLEARED THE DI , PLACARDS REMOVED NO REACTIVATION PROCEDURES APPLY A/C DOWNGRADED CAT I. AIRCRAFT RETURNED TO SERVICE