[AMPS] Heath HL-2200

[Rich Measures]

>Heath HL-2200...  I am in search of a comprehensive source for
>
>modifications on the HL-2200.  Specifically I am interested in
>
>a mod for limiting in-rush current..  any help is appreciated.
>
If you measure the 3-500Z filament inrush current with an oscilloscope, 
you may find that the inrush current is well within Eimac's rating of 29 
maximum inrush amperes.  However, if you start the HL-2200 on the SSB 
tap, the on/off may not last very long.  A fix is to install a step-start 
circuit.  There's one in *Amplifiers* at:
http://www.vcnet.com/measures
The stock RF relay in the 2200 is too slow to keep up with modern radios, 
however, it makes a good step-start relay.  For faster RF switching, see 
Figure 7, or the 1/94 QST article "The Nearly Perfect Amplifier".  
Rich---

R. L. Measures, 805-386-3734, AG6K   


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