Making Measurements 2
Keysight U1251B and U1252B User’s and Service Guide 75
Charge terminal alert
The meter sounds an alert beep when the   terminal detects a voltage level 
of more than 5 V and the rotary switch is not set to the corresponding 
 location. The primary display indicates a flashing “Ch.Err” until the lead is 
removed from the   input terminal. Refer to Figure 2-17 below. 
Figure 2-17 Charge terminal alert