[Heathkit] HP-23(*) differences.

[Robert & Linda McGraw (K4TAX)]

Keep in mind that the HP-23 series of supplies used a full wave voltage 
doubler circuit.  The condition of the filter caps will have significant 
effect on the load/no load voltage.  Sounds like it's time for a cap change 
in the older one of the supplies.

73
Bob, K4TAX


----- Original Message ----- 
From: "Kenneth G Gordon" <kgordon2006 at verizon.net>
To: <yash at aol.com>
Cc: <Heathkit at mailman.qth.net>
Sent: Tuesday, May 08, 2007 3:45 PM
Subject: Re: [Heathkit] HP-23(*) differences.


> On 8 May 2007 at 15:47, yash at aol.com wrote:
>
>>
>> Gorden
>> I have never seen any differances in any hp supply. the 23 and the 23a
>> had 6 v winding the latter b and c didn't. they were all rated at 820
>> vdc no load and 700vdc at 250 ma. load. your supply sounds normal
>> .Unless your hi voltage current draw is higher for some reason... then
>> the hv might decrease just a bit more under the heavier load. good
>> luck dale wt4t
>
> I used the same rig with the two different power supplies: the SB-
> 102, which has a meter position to read the HV.
>
> With the older PS, that meter reads noticeably UNDER 800 VDC,
> no load, and CONSIDERABLY under 800 VDC at even 1/2 load (50
> watts output).
>
> With the NEWER PS, the meter reads slightly over 800 VDC, no
> load, and very slightly UNDER 800 VDC at full load, of around 100
> watts output.
>
> There IS a difference in the PSs, since everything else is identical:
> same rig, same load, same frequency, same tubes, same etc. The
> only thing being different is the PS.
>
> Both PSs operate at normal temperatures.
>
> Ken Gordon W7EKB
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