高手帮忙分析下34401A报错ERR620

dgms17

高手帮忙分析下34401A报错ERR620，有什么思路去维修
AC rms zero failed This test configures to the 100 mV ac range
with the ac input grounded through A4K103. The internal residual
noise of the ac section is measured and checked against a limit of
–10 mV to 70 mV at the output of the rms-to-dc converter.

maitreya

A4K103是个继电器？失效或触点不良？