HMS 07FE-8000-0001-0006: TH Board Disconnected
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HMS 07FE-8000-0001-0006 means the TH board disconnected during the extruder switching process, and asks you to check whether the connecting cable is loose. The timing is the clue: it happens while something is moving, so it is a connection that opens under movement.
A cable that measures perfect on the bench can still break contact at one point in the travel. That is the fault you are hunting.
Where to buy
Anchor the loom so it stops flexing
Adhesive cable tie mounts let you fix the run where it should not move and leave slack where it must. Most intermittent toolhead faults are a loom that is being worked at one point instead of bending along its length.
Ground yourself before touching the board
An anti-static wrist strap costs very little and the board it protects does not. Static damage does not announce itself: it shows up a fortnight later as the same intermittent fault you thought you had fixed.
Give the cable a path of its own
A drag chain carries the cable through the travel at a controlled radius instead of letting it rub and fold. On a machine where the toolhead moves constantly, that is the difference between a cable that lasts years and one that lasts months.
Then reproduce it deliberately
Run the switch repeatedly while gently flexing the suspect section by hand. A fault you can trigger on demand is a fault you have located.
How HMS 07FE-8000-0001-0006 differs from a dead sensor
A permanently absent signal is HMS 07FE-8000-0001-0002. This code is a connection that works until it is moved.
When the motor loses its connection too
The switching motor reports HMS 07FE-8100-0001-0001 for the same class of problem. Method is in troubleshooting and the platform in the Bambu Lab H2D.
HMS 07FE-8000-0001-0006 FAQ
Why only during switching?
Because that is when the connection is being flexed.
Should I just reseat it?
Start there. If it returns, the cable is damaged.
Is a drag chain necessary?
Not required, but it is what stops this recurring.
Can I test it with a meter?
Only if you flex the cable while you measure.
Small connectors cause most of these messages. HMS 0700-9400-0001-0001 means the AMS heater temperature sensor is malfunctioning, and it names poor connector contact first because that is the common cause.
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