Quote:
Originally Posted by orbanp1
The 2 x 135V AC (RMS) voltage would give about 380V DC rectified filtered voltage with no load. So that 370V DC sounds about right. The question remains why would they call that 300V DC?
|
That's exactly what I was thinking! But I still cannot understand how the AF output ECL82 / 6BM8 survives. It has the full HT (370V) on its anode and the screen grid is fed from the +150V line through a 1k resistor (R106). The data sheet at
http://www.r-type.org/pdfs/ecl82.pdf suggests 272V for the anode and screen and a cathode resistor of 650 ohms - FT200 circuit Rk = 390 ohms (R101).
I have set the primary taps on the mains transformer for the maximum of 2 x 117V = 234V and feed this in via a variac, so I'm not over-running. However, it all seems to work and nothing is cooking - but I remain puzzled.
- Peter