Hioki 3283 Clamp meter repair help request

[ntj77]

Hi, I purchased a used non working Hioki 3283 Clamp meter and trying to repair it. Now it is switching ON and measurements are possible except for the "FILTER" option, which is low pass filter especially for measuring VFD. There is no signal at all if I enable "FILTER" key, reading is 0.00.
Can someone please help with a schematic of the filter circuit or at least where to look on the PCB?

[bob91343]

Did you contact the company?  They will probably tell you to send it in but it's worth a try.