[Boatanchors] Bendix High Voltage Supply - Switcheroo
David Stinson
arc5 at ix.netcom.com
Sat Oct 9 17:16:30 EDT 2021
I'm (very) slowly working on a Bendix Skipper 135 marine
AM transceiver, circa 1960s. Primary power is 12 VDC,
It has a receiver full of PNP germanium transistors, of which
I had spares. A few caps and some replaced transistors
and it's working fine on Rcv.
The transmitter uses tube crystal oscillator / PA, powered
by a simple transistorized multivibrator/transformer/
voltage doubler. The power transistors are PNP germaniums
and, like many power germaniums at this late date, they
are leaky. Power supply will only do about half the required
B+ voltages (caps and diodes replaced, no unusual load on
the B+ busses).
Here's the deal- Power PNP germaniums which aren't leaky
are getting hard to find, but NPN Silicon are common as sand
(see what I did there? :-D ) Maybe 2N3055?
I'm thinking I can swap the Collectors and Emitters, move
R34, the Base bias resistor from the Negative buss to the
Positive buss, then play with R34's value until I get reliable
start and minimal dissipation. Diagram attached.
Comments? Ideas?
TNX OM ES 73 DE Dave AB5S
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