The Sinometer HP9810 is an automotive tester and digital multimeter combined in one. For automotive testing, you can use it to measure dwell angle and RPM up to 10,000.
Faults: or open or short circuits of input voltage limit dividers.
To repair, I give a number of photographs of the input circuits of the Sinometer HP9810 instrument.
Sinometer Instruments products, including digital multimeters, are represented in more than fifty countries around the world. Products of various categories of the company are known under various trademarks, for example, a multimeter Mastech, Complee, Sinometer, Sunsand, etc.