[Elecraft] KPA500 faults

[Rick Bates, NK7I]

As I recall, when I got one of the first KPA500 kits available, it was 
also important to note the HV under load... I'd have to dig through 
ancient notes to see what the allowed window should be... or it may be 
in the manual.

That points to the usable power of the house supply circuit; more so in 
old wiring that might not be adequate for such a load (you don't share 
that circuit with a microwave oven).

Mine was borderline, sagged to the low end of that range, on the middle 
post (in a newish home).  When moved to another tap to increase the 
voltage; was still in the 'ok' range for unloaded voltage (it CAN be too 
high).

A little testing and experimentation is needed in setup of the amp; and 
at any new location.

Mine didn't fault in the sag, my goal was a cleaner output with the 
higher voltage while keeping in that window.

73,
Rick NK7I



On 3/2/2022 10:39 PM, Jim Brown wrote:
> On 3/2/2022 9:38 PM, Dr. William J. Schmidt wrote:
>> I have a KPA500 that faults on low (60 VDC) voltage.
>
> Hi Bill,
>
> It MIGHT be faulting because the HV is too low. It's an un-regulated 
> supply, so if line voltage is low, HV will be low. There's a jumper to 
> re-tap the power transformer, accessible with the top off, details in 
> the manual. We used to run into that when running two K3/KPA500 
> stations on the same 2kVA Honda on county expeditions for 7QP and CQP.
>
> 73, Jim K9YC