求助34970A自检报错ERR606怎么解决

dgms17

我的34970A现在自检报错ERR606，看手册好像是ADC有问题，换过LM399，和LM399周边的8脚ADC转换芯片，现在不知道怎么下手了，请高手指点一下
606 Rundown gain out of range This test checks the nominal gain
between the integrating ADC and the A1U205 on-chip ADC. The
nominal gain is check to ± 10% tolerance.