View Single Post
  #2   Report Post  
Old September 24th 08, 04:17 AM posted to rec.radio.amateur.boatanchors
Grumpy The Mule Grumpy The Mule is offline
external usenet poster
 
First recorded activity by RadioBanter: Sep 2008
Posts: 87
Default type 139 chinese receiver pwr slp question



An OB3 voltage regulator tube and a resistor will provide
90V from 120V. So would a 90V zener diode or string of
lower voltage zener diodes in series and a resistor.

The 1.5V could be produced with a series string of silicon
rectifiers and a resistor (maybe two or three. It depends
on their forward conduction voltage.) The power lost in the
resistor(s) for this output voltage will be at least 35W.

For the 90V it's not a bad way to approach it. For the 1.5V
it's kind of crappy but it will work if the power supply can
provide enough power and you like the smell of hot resistors.

You might find the filament circuit in this design useful
and the 105V output could be turned down to 90V.

http://www.dwave.net/~twomules/vtpwr.pdf

If you eventually decide to build a dedicated off-line supply
for the radio this may help.

http://www.dwave.net/~twomules/smps.html


vy73


"Jade's Tech Services" wrote in
:

Hi all;
I have the receiver working well with batteries, 90vdc for plates,
and
1.5v for filaments, ..90v doesnt draw much I, but the I from the 1.5v
batts is 300ma.
I have acquired an acopian 120 volt dc power supply,
I would like to connect the output to a circuit, (hopefully
something
simple)
that will give me 90v and 1.5 v.
any help greatly appreciated, I do have a good junkbox with
resistors ,
the
old power types and 2 watt jobs,
tnx Jim kw3u
I figure why reinvent the wheel when I can be lazy and ask the experts
here.