Heathkit V4 VTVM
The 1949 Heathkit V4 VTVM restoration is complete. The 12ufd 150VDC filter capacitor has been replaced with a new 22ufd 160VDC filter capacitor. The old Selenium rectifier has been replaced with a new 1N4007 silicon diode. The old 0.01ufd 2KVDC and 1KVDC paper capacitors have been replaced with new 0.01ufd 3KVDC and 1KVDC capacitors. The dual “D” cell battery holder has been cleaned and new “D” cell batteries have been installed. The cabinet has been sanded to remove all original paint then a coat of Rustolium Professional primer paint applied and allowed to dry. A coat of Rustolium Granite paint was applied to the cabinet and allowed to dry. The handle was rubbed with steel wool and painted Rustolium Chrome paint. The DC CAL was performed followed by the 3VDC AC BAL adjustment. All switch wafers were cleaned with contact cleaner and blow dry with generous amounts of canned air to remove all residue cleaner. New front and rear mounting screws replaced the old discolored screws. New AC/Ohm probe was made and tested. The “DC Probe” is the Heathkit switchable probe used to measure DC voltage from a 6 volt lantern battery in the left picture. The AC/Ohm probes is used to display measurement of a 10K ohm wire wound resistor. The power indicator was replaced as the original indicator lamp holder failed.