HMS 0700-3500-0001-0001: AMS Temperature and Humidity Sensor Error
LayerWalker is a participant in the Amazon Services LLC Associates Program. We may earn a commission when you buy through links on our site, at no extra cost to you.
HMS 0700-3500-0001-0001 means the temperature and humidity sensor inside the AMS has stopped reporting and Bambu suspects the chip. Nothing about your filament has changed: what you have lost is the measurement, not the storage. An external hygrometer in the unit restores the information for a few pounds.
This is one of the least urgent codes on the machine, and also one of the easiest to work around properly.
Where to buy
![Dry & Dry [1 Quart] Premium Orange Indicating Silica Gel Desiccant Beads (Industry Standard 3-5 mm) - Rechargeable Silica Gel Beads (2 LBS)](https://m.media-amazon.com/images/I/61y14L8nTDL._AC_SL1500_.jpg)
What the sensor was for
The AMS doubles as a dry box, and the sensor is how it tells you whether that is working. It does not dry anything by itself; it reports the conditions inside so you know when the desiccant is spent. Losing it means you are flying blind on a job the desiccant is still doing.
Replace the information, not the unit
A small battery hygrometer sitting inside the AMS gives you the same number the sensor used to. Aim for 20 % relative humidity or below for most materials. That single reading tells you when to recharge or replace the desiccant, which is the only decision the sensor was ever informing.
Check the desiccant while you are in there
Indicating silica gel changes colour when it is saturated, and spent desiccant in a sealed box is worse than none because it holds moisture against the filament. Recharge it in an oven or replace it. The broader approach to keeping filament dry is in filament dry boxes.
When drying is the actual problem
If prints have gone stringy and brittle, the filament is already wet and no amount of storage fixes it — it needs active drying. Options sized for this machine are in the best filament dryer for Bambu, and the general case is in filament dryers.
What HMS 0700-3500-0001-0001 is safe to ignore
The code does not affect feeding, switching, or print quality. Unlike the motor and odometry faults in this group it has no mechanical consequence at all, so it can wait for a service visit you were having anyway. Snapping filament, which damp storage does cause, is HMS 0700-2000-0002-0003.
HMS 0700-3500-0001-0001 FAQ
Can I keep printing?
Yes, with no restrictions. This is a reporting fault.
Is the sensor replaceable?
It is part of the AMS board, so the practical fix is a board or unit swap rather than a component.
Will a reading of zero damage anything?
No. The machine does not act on the humidity value beyond displaying it.
Does a DIY dry box help here?
It gives you a second, independent store for sensitive materials, which is a reasonable response — see DIY filament dryers.
LayerWalker
Print defect diagnosis, calibration procedures and parts that actually fit. Corrections welcome through the contact page.
