
Bill Validator Diagnostic Flow
VendnetUSA 3013 / 3014 / 3015 / 3020 / 3021 / 3022 / 3023 / 3024 / 3025 / 3026
Bill Validator Diagnostic Flow
This process guides you through checking the bill validator to determine why it might not be accepting currency, starting with simple physical checks and moving toward connectivity verification.
- Validator harness connector shows signs of melting or burning: Stop immediately. Disconnect machine power. Escalate to licensed technician.
- If the issue persists after these steps, please contact a qualified technician, as further diagnosis of the validator unit or control board requires specialized expertise.
- If any electrical supply or wiring inspection is needed, a qualified technician must perform the work.
Checklist
Guided Diagnostic Steps
Work from low-risk checks toward technician-level inspection only when evidence supports it.
You can read or print the route now. The first checkbox click opens the service contact gate.
- 1
Shine a flashlight into the validator slot and bezel opening to check...
operator-intermediateunpluggedShine a flashlight into the validator slot and bezel opening to check for visible obstructions.
Stop conditions- If the issue persists after these steps, please contact a qualified technician, as further diagnosis of the validator unit or control board requires specialized expertise.
- If any electrical supply or wiring inspection is needed, a qualified technician must perform the work.
Expected: Initial condition is documented before deeper diagnosis.
Evidence to note: note
- 2
Verify the main harness connecting the validator unit to the control...
operator-intermediateunpluggedVerify the main harness connecting the validator unit to the control board is fully seated.
Stop conditions- If the issue persists after these steps, please contact a qualified technician, as further diagnosis of the validator unit or control board requires specialized expertise.
- If any electrical supply or wiring inspection is needed, a qualified technician must perform the work.
Expected: Initial condition is documented before deeper diagnosis.
Evidence to note: note
- 3
Shine a flashlight into the validator slot and bezel opening
operator-intermediateunpluggedShine a flashlight into the validator slot and bezel opening
Stop conditions- If the issue persists after these steps, please contact a qualified technician, as further diagnosis of the validator unit or control board requires specialized expertise.
- If any electrical supply or wiring inspection is needed, a qualified technician must perform the work.
Expected: Result is documented before continuing the route.
Evidence to note: note
- 4
If a bill or foreign object is visible, carefully remove it using fin...
operator-intermediateunpluggedIf a bill or foreign object is visible, carefully remove it using fingers or needle-nose pliers
Stop conditions- If the issue persists after these steps, please contact a qualified technician, as further diagnosis of the validator unit or control board requires specialized expertise.
- If any electrical supply or wiring inspection is needed, a qualified technician must perform the work.
Expected: Result is documented before continuing the route.
Evidence to note: note
- 5
Do not use sharp metal tools that could damage the belts
operator-intermediateunpluggedDo not use sharp metal tools that could damage the belts
Stop conditions- If the issue persists after these steps, please contact a qualified technician, as further diagnosis of the validator unit or control board requires specialized expertise.
- If any electrical supply or wiring inspection is needed, a qualified technician must perform the work.
Expected: Result is documented before continuing the route.
Evidence to note: note
- 6
Access the control panel area
operator-intermediateunpluggedAccess the control panel area
Stop conditions- If the issue persists after these steps, please contact a qualified technician, as further diagnosis of the validator unit or control board requires specialized expertise.
- If any electrical supply or wiring inspection is needed, a qualified technician must perform the work.
Expected: Result is documented before continuing the route.
Evidence to note: note
- 7
Locate the main harness connecting the validator unit to the control...
operator-intermediateunpluggedLocate the main harness connecting the validator unit to the control board
Stop conditions- If the issue persists after these steps, please contact a qualified technician, as further diagnosis of the validator unit or control board requires specialized expertise.
- If any electrical supply or wiring inspection is needed, a qualified technician must perform the work.
Expected: Result is documented before continuing the route.
Evidence to note: note
- 8
Verify the connector is fully seated
operator-intermediateunpluggedVerify the connector is fully seated
Stop conditions- If the issue persists after these steps, please contact a qualified technician, as further diagnosis of the validator unit or control board requires specialized expertise.
- If any electrical supply or wiring inspection is needed, a qualified technician must perform the work.
Expected: Result is documented before continuing the route.
Evidence to note: note
- 9
Disconnect the harness, inspect pins for damage, and firmly reconnect
operator-intermediateunpluggedDisconnect the harness, inspect pins for damage, and firmly reconnect
Stop conditions- If the issue persists after these steps, please contact a qualified technician, as further diagnosis of the validator unit or control board requires specialized expertise.
- If any electrical supply or wiring inspection is needed, a qualified technician must perform the work.
Expected: Result is documented before continuing the route.
Evidence to note: note
- 10
Restore power to the machine if it was unplugged. Insert a crisp, un...
operator-intermediateunpluggedRestore power to the machine if it was unplugged. Insert a crisp, un torn bill of a standard denomination to test the validator.
Stop conditions- If the issue persists after these steps, please contact a qualified technician, as further diagnosis of the validator unit or control board requires specialized expertise.
- If any electrical supply or wiring inspection is needed, a qualified technician must perform the work.
Expected: Result is documented before continuing the route.
Evidence to note: note
Tools for this route
Location Help
Where to find this
Use this as orientation before touching the machine. It is location help, not a repair instruction.

Start at the front door payment column; match the display, keypad, coin, bill, or card device to the symptom before opening deeper panels.
- Accepts and processes cash (bills) into the machine.
- Mars Validator unit
- Validator harness
- Validator bezel (frame)
cabinet glass front
wiring harness
bill validatorParts status
Exact public parts list not verified yet. Use this route to identify the system before ordering.
Candidate areas for part verification
