Patient couch control troubleshooting — KGTSM / KGTSP / slide servo amplifier faults
Use this page when the patient couch's control electronics are the suspect — the couch won't go UP or DOWN, vertical movement works locally but the console reports a remote-control error, or the couch-top horizontal (slide) drive throws a servo alarm or a KGTSM SLIDE message. It walks each symptom from the printed check to the fix, preserving every voltage, connector, LED, and alarm number named i
Tools & parts
| Item | Part number | Qty |
|---|---|---|
| UP line circuit protector (CP5) | n/a in source | |
| Circuit protector, slide/horizontal drive supply (CP51) | n/a in source | |
| Terminal board, gantry (TB380) | n/a in source | |
| Terminal board, gantry input (TB1) | n/a in source | |
| Fuses, gantry (F116, F117, F118) | n/a in source | |
| Fuse, KGTSP (F6) | n/a in source | |
| Contactor (MC112) | n/a in source | |
| 24-VDC power supply, gantry (PS111) | n/a in source | |
| 24-VDC power supply, gantry (PS380) | n/a in source | |
| Tilt overrun switch | n/a in source | |
| KGTSM PWB (gantry control) | n/a in source | |
| KGTSP PWB | n/a in source |
Safety
Hazard: This checklist is worked with the gantry and patient couch under power, and several steps deliberately command UP/DOWN vertical motion or couch-top horizontal (slide) motion while you measure voltages, watch LEDs, or read feedback pulses
Consequence: unintended/unexpected couch or couch-top motion during the check can pinch or crush hands, tools, or clothing caught in the travel path, rollers, belt, or clutch/brake area
Avoidance: before starting work, confirm that the gantry and the patient couch are NOT interlocked; keep hands, tools, and clothing clear of the couch travel path, belt, and clutch/brake area before commanding any UP/DOWN or slide motion for a check
Hazard: Nearly every check in this table is a live-circuit electrical measurement: 200 VAC at CP5/CNN1/TB380/TB1 and at the slide servo amplifier's three-phase CN POWER input, and 24 VDC at the clutch/brake terminal board and KGTSP CN504
Consequence: electric shock
Avoidance: treat every voltage check in this table as live-circuit work; verify isolation/PPE per the Gantry/Couch Control volume before opening an electrical enclosure or probing a connector
Hazard: Setting the couch top to FREE status (alarm 16 / alarm 24 diagnosis) disengages the clutch/brake so the couch top can be moved by hand
Consequence: an unrestrained couch top can move unexpectedly and pinch hands or strike nearby equipment or personnel
Avoidance: clear the travel path and control the couch top by hand while it is in FREE status; do not leave it unattended in this state
Full step-by-step for Patient couch control troubleshooting — KGTSM / KGTSP / slide servo amplifier faults
All 76 steps are documented in the FSELIB Activion16 (TSX-031A) service manual — re-authored, web-first, with the real figures from the source.
Open the full procedureRelated Couch/Table guides
Source: 2D201-112EN*D §3.9.6 Patient couch control troubleshooting — §3.9.6.1 Vertical movement system, §3.9.6.2 Couch horizontal movement (pp.322-328). Preview re-authored by FSELIB — the full procedure with figures and steps is in the paid service manual.