During Calibration: 1. Check If K7 Contactor On AMX1A4 Panel Pulls In - Check for Welded Contacts 2. Check that No Wires Or Side Cover Insulation Interfere With K1 Thru K6 Contactors On AMX1A4 Panel 3. Check for Bad Crimp On Red Lead To AA Of Q3 On AMX1A4 Panel 4. Check for Defective Jumper Harness From J3 On 1 KHZ Inverter Driver Board To J7 On Filament kVp Board 5. HV Cathode Cable May Be Shorted 6. Filament kVp Board may be defective 7. 1 KHZ Inverter Driver Board may be defective 8. Check Spark Gaps On HV Transformer Tank For 0.010” 9. Check for Location Of Black & White Leads On Power Module SCR Q3 Block On AMX1A4 Panel 10. Power Module SCR Q3 Block may be defective 11. Check If EXP START CMND Is Shaky (This Is Like 439 error During Applications). EXP START And SCR HI/LO Are Single Pulses 12. “XRAY ON” Going Low = Bad Tap Relay Contact(s) 13. Bad Hand switch 14. Defective Rotor Control Board - Also Check Stator Rotor Lead(s) For Continuity 16. Bad XRT - (HI FIL LIMIT ERROR) With 439, 467, OR 469 Errors Alone - Usually At Higher kVp (kVp Waveform Will Be Low On The Front End, Even In Check-Sum Bypass Mode) 17. Bad High Voltage Transformer Tank 18. C5 Leaky Or Bad 19. 439 and 469 errors – Check ALL Leads That Exit The AMX1A4T1 Autotransformer — Look For Pinched Or Shorted Leads To Ground 20. Check Pin Spread On Both Ends Of Cathode Cable (Also Check for Proper Amount Of Grease In High Voltage Cable Wells) 21. Refer To ERROR 439 - Item 2. During Application 1. There May Be Oscillations Or Trash On The “XRAY ON” Signal (could be Bad Tap Relay Contact(s) 2. could be An XRT Spit Or Bad XRT 3. Possible CPU Board Failure 4. Hand Switch Or Coil Cord Failure 5. Check for weak (“soft”) batteries/cells. 6. Tap Relay Contact Bounce - Replace 1 KHZ Board 7. Side Cover Fish Paper Insulation Impacting Tap Relays When Cover Installed 8. Bad Handswitch 9. Bad Rotor Board 10. Check Stator Lead(s) Continuity 11. Also refer to Faults “During Calibration” Above Notes: 1) Verify that on Older Units that FMI-10231 Was Accomplished (Upgrading The Drive Control Board 46-232834G1-C/G1-D). 2) Random 200 Series Errors could be Caused By Loose Connections At K1 And K2 Drive Relays, Or Bad Motor Brushes (single brush assembly is orderable part # 2170759). Check for Curled Fish-paper Insulator On Rear Of The Cassette Draw That Might Be Cutting Into The Cable Assemblies. 3) Runs On Charger Board J2-5 To K215 And On Drive Amp Board J10 To K145 And J5 Or J6 To K145 Burned Open = Shorted Brake Assembly (refer to CQA 911200) 4) Stall LED(s) Lit On Drive Control Board -Try Re-Calibrating The Handle - Also could be Caused By Poor Ground Connections On AMX1A2TS1-4, 5, 6, Or 7 (located Behind LVLE power supply) 5) “RELEASE HANDLE” Message And Unit Stops (Intermittently) - F9 Fuse/Fuse-holder Stressed 6) AMX-4 Jerks Forward-Faster Than MAX Speed — +15VDC (LVLE power supply) Dropped To +9VDC. Replace early production LVLE power supply made by Power Design Inc. (known as part #46-270724G1 or T3497L), replace with part # 2366118. Refer to CQA 965947 7) Unit Drives at Slow Speed Initially (no error codes), And Eventually Gets Up To Proper Speed. SOLUTION: On Newer Style Base Assemblies, With The Newer Motor Mounting Assy. - Check for Drive Belt Tightness (The Motors Are NOT Spring-Loaded; They Are Tightened Down After The Proper Belt Tension Is Obtained.