Re: 454 screen brightness issues?


Albert Otten
 

Hi Jack,

Where should I be looking for those DC restorers, in the -1920v?
The 454 has no DC restorers. The HV transformer has separate windings for the grid and the cathode circuit. The rectified voltage for the grid can be reduced somewhat by the grid bias pot R1447 (in the divider chain with R1442-R1446) and is stacked on the voltage supplied by the Z-axis amplifier.
When you follow Mike's suggestion and use a pdf of the manual, you will note that the waveform at TP1349 is almost invisible. The blue picture in the paper manual is also very faint. The voltage switches between the 2 written values 17.7 V and 6.75 V.

Albert

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