Ku7i at WORLDNET.ATT.NET
Tue Feb 29 20:21:13 EST 2000
I have a power supply out of my Northern Radio Company N542 KW HF amp. The
amp runs a pair of 3-500Zs (not for sale). The power supply (which is for
sale) is designed to be bolted into a 19" rack. It uses 120 vac input only.
The output is about 4200 volts at 1/2 amp or so. The xmfr output is abt 3900
volts which goes into a dc filter choke which looks like it is rated at
around a half amp. There are four oil filled caps which are 4uF 2500vdc
units, probably series-paralleled. The unit is energized by applying 24vdc
or 12vdc to the primary power relay. I do not know for sure if it is a 12 or
24 volt coil since it energizes on 12 volts just fine. The output is a
Millen HV connector (just one for the B+, B- must be chassis ground). The
topside chassis is full of thick dust/light grime. Not bad. With a high
pressure air hose most of it would clean off. The underside looks perfect.
It also uses two 25k ohm 225 watt bleeder resistors. I have no scat for this
but it is a very very simple design that could easily be traced out by hand
and drawn out from reverse. It DOES work. I tested it on my big amp that
runs a pair of 3-500Zs and with 1350 watts out of the amp the power supply
dropped to abt 3000 volts. Not super good regulation but considering 120 vac
line not really bad either. The choke is not resonated. If you did resonate
it the regulation would improve significantly.
Also has a fused line cord with a fuse on each side. There is a 8 pin octal
socket on the rear of the chassis for relay power and I think there might be
120 volts to one of the pins. I removed the two leads that go to the pri
power relay so I could verify operation. Otherwise it is totally stock. This
power supply is 100% complete and ready to use. No metering at all. The
front panel is totally blank except for the two fuses. The front panel looks
fair, about a 6 or 7 out of 10. It would not be hard to remove the panel and
repaint it. If you need a good 4000 volt supply at 1/2 amp to do amplifier
work then maybe this is a good candidate. It is kind of handy having it
wired for 120 vac since it is "portable" at abt 75 pounds.
Price is $215 shipped lower 48. Will double box and insure via UPS ground.
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