What Does Err1 Mean?
Reviewed by vending machine technicians · Last updated July 30, 2026
Quick Answer
Err1 = Tray home switch error — a product tray did not return to the closed position after vend cycle
Severity: Critical · System: Sensit Combo Vending Machine
⚠️ SAFETY WARNING — This code indicates a critical issue. Stop operation and diagnose before continuing.
CRITICAL — Machine Locked
Tray home switch error — a product tray did not return to the closed position after vend cycle
Equipment: AMS Sensit Combo Vending Machine
Step-by-Step Troubleshooting
- Open the machine door and visually check all trays — look for one that is not fully seated in the closed position
- Remove any product that may have fallen behind the tray and is preventing full closure
- Inspect the tray home switch (microswitch at the rear of each tray slot) for physical damage or misalignment
- If the error persists after clearing, run the tray home test from the AMS Sensit service diagnostics menu
Detailed Troubleshooting Procedure
- Power cycle the machine — turn off the main power switch for 30 seconds, then restart. This clears transient tray position errors from sensor glitches.
- Open the machine door and visually check all trays — look for one that is not fully seated in the closed position. Push each tray firmly until it clicks into the locked position.
- Remove any product that may have fallen behind the tray and is preventing full closure. Check behind and underneath each tray shelf for displaced items.
- Inspect the tray home switch (microswitch at the rear of each tray slot) for physical damage or misalignment. The switch actuator arm should move freely and click audibly.
- If the error persists after clearing, run the tray home test from the AMS Sensit service diagnostics menu. The display will show which tray is reporting a home switch error.
- Replace the faulty microswitch if the diagnostic points to a specific tray. The microswitch is held by one screw and has a simple spade connector — a 10-minute replacement.
Common Causes
- Product fallen behind the tray — a displaced item prevents the tray from closing fully, keeping the home switch open
- Damaged tray home microswitch — the switch actuator is bent or broken from repeated tray closures
- Misaligned tray guide rails — the tray slides out of alignment, missing the home switch actuator
- Tray not pushed in fully after restocking — the most common cause during routine service visits
Parts & Cost Guide
| Item | Details |
|---|---|
| Parts Needed | Tray home microswitch (AMS part #SW-AMS01) Tray guide rail clips (AMS part #RCL-010) Tray latch assembly (AMS part #LCH-020) |
| Estimated Repair Cost | $5–15 (DIY: microswitch replacement) · $100–200 (technician service call) |
| Expected Downtime | 5–10 minutes to reseat trays; 15–30 minutes for microswitch replacement |
About This Data
Error code definitions and troubleshooting steps compiled from AMS service manuals, field technician reports, and equipment documentation. This is an independent reference — not affiliated with or endorsed by AMS. Brand names are trademarks of their respective owners and used for identification only.
Published: 2026-07-05 · Always consult your equipment's official service manual and a qualified technician before performing repairs involving electrical or refrigeration systems.
⚠️ Safety: Vending machines operate on 115V AC and may contain pressurized refrigerant. Disconnect power before servicing. If unsure, contact a qualified technician.
Related Error Codes
Codes from the same brand, equipment type, or error code family:
Frequently Asked Questions
How serious is AMS error Err1?
Severity: RED. Tray home switch error — a product tray did not return to the closed position after vend cycle. This error locks the machine and requires immediate attention.
Can I fix AMS error Err1 myself?
Many AMS error codes can be resolved by following the troubleshooting steps on this page. Start with power cycling the machine. If the error persists after completing all steps, contact a qualified vending technician. Do not attempt repairs involving the refrigeration system or 115V electrical components unless you have appropriate training.
What parts do I need for AMS error Err1?
The required parts depend on the root cause identified during troubleshooting. Common parts include AMS Sensit vending tray home switch microswitch shelf position. Always diagnose the specific cause before ordering parts — the error code alone does not tell you which component has failed.
Is Err1 caused by a problem with the tray motor?
No — Err1 is specifically a home switch error, meaning the control board does not detect that the tray has returned to the closed position. The tray motor (which moves products forward on the Sensit combo) is a separate system. If the tray motor fails, you would see a different error code.
How do I identify which tray is causing Err1?
The AMS Sensit display will show the tray number when Err1 is active. You can also run the tray diagnostic in service mode — each tray's home switch status is displayed. The tray that shows 'OPEN' when it is physically closed has the faulty switch or obstruction.
Can I disable a problematic tray to keep the machine running?
Yes — in the AMS Sensit service menu, you can disable individual trays. Navigate to the tray configuration and set the problematic tray to 'DISABLED'. The machine will continue to vend from all other trays. This is a good temporary fix until you can replace the microswitch.
How do I prevent Err1 errors after restocking?
Always push each tray fully closed until it clicks. Verify the tray is locked by giving it a gentle pull — it should not slide out without lifting the latch. Check that no products are sticking out past the tray edge, as these can catch on the cabinet frame during closure. Train all restocking personnel on proper tray seating procedure.