Meat Plow wrote in message
...
On Wed, 28 Oct 2009 10:30:08 -0000, "N_Cook" wrote:

According to owner , bought it off company rep a few years ago and is
export
version prototype.
Blew a fuse a few weeks back , runs still ,after fuse change (self heeled
cap?) but excessive hum.
450V rating ps electros but I measure 488V on the HT rail and varying ac
(4
to 5 volt ac measured via 1uF, 1500V polyprop), perhaps seriesed-up, but
3
in there, I've not taken apart yet.
The neon lit mains switch looks more like a light bulb , runs too hot to
keep your finger on, I suspect droppers for USA mains inside. No serial
number on the chassis. Have yet to test the valves but I suspect probably
ok, any advice on dealing with the HT/caps issue? What is the HT rail
supposed to be for USA issue ones ? Any schematic for the pa / ps
anywhere ?


The HT would depend on what tubes were in the output. The mains switch
illumination is derived from where?

I've seen HT from 400 to 700 volts depending on the tube and
manufacturer but if you have 450v caps your HT should be what minus 10
to 15% of the 450v caps..

What are the tube heater voltages?

Testing the valves at the moment , next time I power up I will use a variac
set for 210V or so and try and work out the 0/110/210/230 settings