Got this old Simpson 260 5p Volt-Ohm-Milliammeters fro free. Was curious that it has high voltage range up to 5000V ! Now I want to make sure it works and see if I can measure some high voltage circuits !
So lets do teardown and troubleshooting !

Specs

Simpson 260 Series 5P Specifications

DC VOLTAGE

Ranges 250mV, 1V, 2.5V, 10V ,25V, 50V, 250V, 500V, 1000V
Accuracy 2% of full scale * Sensitivity 20K per volt

AC VOLTAGE

Ranges 2.5V, 10V, 25V, 50V, 250V, 500V, 1000V
3% of full scale * Sensitivity 5K per volt
Rated Circuit-To-Ground Voltage 1000V (AC or DC) max.

DECIBEL

5 Ranges -20 to +50dB * Reference 0dB= 1mW into 600Ω

DC CURRENT

Ranges 50μA, 1mA, 10mA, l00mA, 500mA, 10A
Accuracy 1.5% full scale 5OμA, 2.0% of full scale, all other
Voltage Drop: (Nominal) 250mV on 50μA , 1mA; 255mV on 10mA , 10A; 300mV on 100mA, 500mV on 500mA

RESISTANCE

Ranges Rx 1, Rx 100, Rx 10K
Accuracy 2.5° of arc on Rx1, 2.0° of arc on other
Maximum Indication 0-2KΩ, 0-200Ω, 0-20MΩ