Originally Posted by littlerepairshop
The 5AR4 seems to be only pulling 590V instead of 640V, and the screens of the 6L6's are seeing 209V instead of 265V, while the grids have -107V instead of -52V.
What was your voltage reference for those measurements? On the schematic you will notice that 0V is labeled as the voltage on the cathodes of the 6L6 tubes. In other words after the rectifier and 6L6 plates, all voltages listed are relative to the 6L6 cathodes, because the grid and screen voltages are biased up by the voltage on the cathodes (which voltage is user adjustable).
For an accurate (relative to the schematic) reading of those voltages quoted you need to measure with pos meter probe on the point you want to measure and neg meter probe on the 6L6 cathodes.
Now, you may still determine the HV supply isnít working correctly, but you must do the measurements with proper voltage reference first before coming to that conclusion.