[Boatanchors]Heath HP-20 versus HP-23

[Richard Post]

Phil's note on powering an AF-67 triggered a question for me.  I was 
given a Swan 175 monobander transceiver.  Its manual has instructions 
for modifying a Heath HP-20 for power supply.  Don't have an HP-20. 
Do have HP-23. The schematic for the HP-20 shows a transformer 
secondary AC voltage of 260 and the HP-23 series have a secondary AC 
voltage of 268 according to their schematics.  However, the HP-20 
schematic shows its DC out at 600 volts while the HP-23 shows 820 
volts.  Both use a voltage doubling circuit.  The HP-20 has a 
slightly larger (lower resistance) bleeder.  My question:  Is the 
HP-20 rated at load versus the HP-23 rated at no-load?  Multiplying 
both the AC outputs by 2.8284 results in 735 for the HP-20 and 758 
for the HP-23?

What am I missing in this picture?

Thinking of using the HP-23 for the Swan.

73,
Rich

Boatanchor Pix

<http://www.qsl.net/kb8tad>




At 7:35 PM +0000 6/22/04, Philip B Atchley wrote:
>Hi all,
>Elmac AF-67:  This transmitter also belongs to Don (W6LRG) and hasn't
>been put on the air since he acquired it, primarily due to lack of a
>suitable power supply.  He has an extra Heathkit HP-23A (he has lots of
>Heath stuff) that I'd considered trying to modify for use with the AF-67.
>  After lengthy consideration I don't think that's the way to go.  It
>would require a bucking transformer to lower the 750-800 Volts down to
>600 or less, THEN an additional transformer for the AF-67 filaments.  I
>will probably try to acquire either a Heathkit HP-20 (which has ideal
>Voltage rating for the AF-67) or the Elmac PS-2 supply , any condition
>and overhaul/repair as required.
>
>THEN, after getting the Elmac up and running I'll be a position to do
>actual comparison tests between the two transmitters for things like
>stability, key clicks, ease of tuning, audio etc.
>   
>73 from the "Beaconeers Lair",
>Phil, KO6BB
>