HMS 0700-0200-0002-0002: Filament Odometer Has No Signal
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HMS 0700-0200-0002-0002 means the AMS odometer has no signal and the odometer connector may have poor contact. The odometer counts filament as it passes, so without it the AMS cannot track how much has been used or whether it is moving at all.
An odometer is an optical sensor watching a slotted wheel. It produces a stream of pulses, and either the pulses arrive or they do not.
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Look at the signal itself
A handheld oscilloscope shows you the pulse train while you turn the wheel by hand. That is the one measurement that settles it: pulses present means the sensor works and the fault is downstream.
Understand the part by having one
A slotted optical sensor module is the same kind of device for a few pounds. Having one lets you see what a healthy output looks like before you judge the one in the machine.
Probe without three hands
Test hook clips grip a pin and stay there while you turn the wheel and watch the screen. Holding a probe against a 2 mm pad with one hand is how pads get shorted together.
Then work the connector
Unplug and reseat it, then wiggle it gently while watching the trace. A signal that appears and vanishes under light pressure is the poor contact the message names.
How HMS 0700-0200-0002-0002 differs from a sensor fault
A sensor that reports nonsense rather than nothing is a different class of problem, as with HMS 0700-3500-0001-0002. No signal means silence.
What else lives on that loom
The heater sensor reports HMS 0700-9400-0001-0001 when it loses contact. The layout is described in the AMS hub guide and the system in printers with an AMS.
HMS 0700-0200-0002-0002 FAQ
What does the odometer measure?
Filament travel, by counting pulses from a slotted wheel.
Can I print without it?
Often, but length tracking and some safety checks stop.
Do I need a scope?
It is the fastest honest answer. A meter will not see pulses.
Could debris be the cause?
Yes. Dust in the slot blocks the beam as surely as a broken wire.
Position signals are their own class of fault. HMS 0700-4000-0002-0002 means the filament buffer position signal is wrong, and an analogue reading usually goes wrong smoothly rather than all at once.
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