[Heathkit] HP-23(*) differences.

[Kenneth G. Gordon]

Well, another problem I have discovered: I have two HP-23(*) 
power supplies, both completely rebuilt with all new diodes and 
filter caps.

One model is an early model of HP-23 (no suffix) while the second 
one is an HP-23B, two models later.

I installed a DPDT-Center-off toggle switch in the HP-23 to enable 
easy switching from 250 to 300 VDC for the LV as is done in the 
HP-23B and others, and have used it for over a year with my HW-
101 and have experienced no problems whatever.

However, I have always felt that the HV was low in the HP-23, 
despite the fact that it runs cool and works fine in every other way.

Recently, while restoring a basket-case SB-102 to operation, I 
discovered that the HP-23B's HV output is around 800 VDC, even 
under load, while the HP-23's HV output is below 800 VDC at no-
load, and drops to around 725 VDC under full-load. The difference 
is almost 100 VDC.

Does anyone know whether or not Heathkit uprated the power 
transformers in their later model HP-23(*)? It sure looks like it to 
me!

Ken Gordon W7EKB