The potential causes for the garbled characters displayed by the electronic scale encompass:

1. Inadequate battery contact: Poor battery contact may result in unstable signals. A blade can be employed to delicately shift the opening in the middle of the battery socket to augment the battery's contact area.

2. Connector problems: Detachment of the connector or the dislodging of solder joints can impede data transmission. Endeavors could be made to tighten the connector or undertake repairs.

3. Load cells issues: The sensor being exposed to heavy pressure or impact can lead to excessive linearity and the manifestation of garbled characters, demanding professional maintenance.

4. Mainboard problems: Corrosion or other forms of damage to the mainboard can also give rise to garbled characters, necessitating professional inspection and repair.