Tektronix 422 Repair/HV Troubleshooting

“Totally unexpected find” is the excuse for this one. I was shopping for tubes and saw this one in the aisle next to the tubes, covered in mud.

Anyways, the second excuse for acquiring one more oscilloscope is – it is small, cute, and tiny, Comparison with Tek 211 here.

211

The entire exercise is documented here in a video.

 

Some of the items/pics explained in the video are here.

1. Power supply unit – can not be turned on by itself due to an AC interlock in the indicator unit. You can bypass it by directly plugging power to the transformer

Interlock-JumperInterlock

 

2. HV oscillator – Oscillator/Driver in power supply and HV transformer / rest of the circuitry to drive the CRT is inside the indicator unit.

HV-MultiVib

3. Two types of VR Tubes are in use, in addition to Zeners.

a) In HV regulation GV4S- 1400, for 1400 V reference. This is a ruggedized HV regulator tube.

HV-REg

b) In the indicator unit regulator, ZZ1000, 81 V reference.

Indicator-Regulator

 

 

 

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