This Hickok TV-7 D/U tube tester was taking dust untill I had time to restore it. Although the top cover was missing, it is in good condition. As a start I replaced the power cable and cleaned the front plate including all the knobs and sockets.
Hickok TV-7 D/U with serial no. 365
R102, R103 and R104 (47Ω/1Watt (5%)) – These Carbon resistors are located on the Grid, Plate and Screen rotary switches. Since it is very tight around the switches gently cut them loose and leave enough wire in place to connect the replacement.
C102 (0.1µF/600Volt) – replaced with 100nF/600Volt WIMA MKP capacitor.
C103 (100uF/15Volt) – replaced with Philips 100uF/50Volts electrolytic capacitor.
CR101 (Copper Oxid) – replaced with two 1N4007.
The original two wire power cable was replaced with a more secure three wire version. (connect the ground wire to the front plate)
All contacts of the rotary switches and tube sockets should be cleaned. It is also recommended to take apart R127 (2x 150Ω/15Watt) in order to clean and lubricate it (vaseline).
A complete calibration of the Hickok TV-7 D/U was done following the original instructions step by step. It will cost some time and effort but it will pay off. I did a final check with a set of calibration tubes from Jac Music, the result was perfect!
Hickok TV-7 D/U completely restored and calibrated
If you have questions or comments just contact me.