Tektronix 2246A faint readout


Jon Harrison-Hughes
 

Hi all,

Having repaired the power supply I've now powered the 'scope up. I've measured the calibration signal on all 4 channels, the buttons and switches all seem to work and the self tests pass.

However I seem to have an issue with brightness on the display, particularly with the readouts

1) The traces only appear if the A intensity is turned towards fully clockwise, readable but not exactly burning the phosphor! (self test shows this pot can be adjusted between FF and 00)
2) If the readout pot is turned fully clockwise the readout can be seen very faintly, much fainter than the traces
3) Pressing beam find blanks the display completely

Any hints and tips on where I should start with this issue ?

Thanks,

Jon

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