What was found
NR 1 ENGINE START VALVE INDICATING WITH START LEVERS OFF. GROUNDED-YES. REF B737-800 WDM 80-11-11-1 - AT NR 1 ENGINE START VALVE CONNECTOR DP1202 PIN 2, FOUND 22V DC WITH NR 1 ENGINE START SW "OFF" AND WITH NR 1 ENGINE START VALVE C/B OPEN. CONFIRMED SAME 22V DC PRESENT AT S266 ENGINE NR 1 START SW CONTACT 1B, REF WDM 49-52-31-2 AND WDM 49-62-11-103. WHEN APU FIRE SW POWER C/B (C1544) WAS OPENED, 22VDC WAS NO LONGER PRESENT AT S266 CONTACT 1B AND REMAINED GONE AFTER C/B WAS RESET. CYCLED APU FIRE SW AND RECHECKED. VOLTAGE WAS NO LONGER PRESENT AT S266 OR DP1202. PERFORMED APU FIRE DETECTION OPERATIONS TEST, PER B737-800 AMM 26-15-00-710-801, ALL TESTS PASS. MANUALLY OPERATED NR 1 ENGINE START VALVE, FOUND START VALVE BINDING AND DIFFICULT TO CLOSE MANUALLY. R & R NR 1 ENGINE START VALVE, REF B737-800 AMM 80-11-03. VALVE LEAK AND OPERATIONS TEST GOOD. STARTED NR 1 ENGINE, STARTED AND OPERATED NORMALLY.