[Elecraft] K3 F6 Fault coupled with KPA1500 power input fault

[RICK SCHMIEDT]

Thanks for your input Dick. I do have all those items set up in my K3 and it and the amp have been running fine for many years. On the KPA1500 GroupsIO page, someone who had this problem suggested that the protection diodes on the input circuit to the KPA may be bad.  He fixed it by buying new diodes and putting them in.  I also checked out the amp using low power (5W) from the K3 and the KPA still goes into input over-power mode (fault 60) with no sign of any power surge from the K3, so I’m thinking the problem is in the KPA1500. The K3 seems to run fine barefoot and when the amp is in bypass mode.  Now I’d love to find a circuit diagram and part numbers for the amp so I can trace what’s going on myself. Any other suggestions?
Sent from my iPhone

> On Jan 7, 2025, at 1:27 AM, Dick Dievendorff <dick at elecraft.com> wrote:
> 
> I’d verify that the K3 menu item PWR SET is PER BAND and the KPA1500 menu item RADIO TYPE is K3.  Verify that the AUX cable connects K3 to amp.
> 
> Then on each band, put the amp in OPER, turn the K3 power way down, then key down and advance K3 power level until the amp power is right.  
> 
> The K3 should have two separate stored power levels for each band, one  each for amp in OPER and STBY.  My K3 changes power from 100 to about 25 watts when I change the KPA1500 from STBY to OPER.
> 
> It sounds like your K3 is putting out 100 watts with the amp in OPER.  That’s way too much.  20 to 30 is closer.  It’ll vary band to band.
> 
> 
> 73 de Dick, K6KR
> 
>> On Jan 6, 2025, at 14:56, RICK SCHMIEDT <schmiera at bellsouth.net> wrote:
>> 
>> Hey all,
>> I have a 7000 serial number K3 that has performed flawlessly over the last 10 years.  But during the ARRL RTTY Roundup, my KPA1500 faulted with the message:
>> Fault: Power input 102 Watts.  Then I noticed that there was a Fault 6 that flashed by on the K3 screen.  It now does this on all bands and into a dummy load.  It doesn’t seem to happen when the low power amp in the K3 is used (less than 13 Watts).
>> 
>> Without the amp in line, the K3 seems to work normally and the output power stays where it should.  I know this topic has been covered before, but I’m not finding a solution.  Can anyone point me in the right direction?  I have not contacted the Home Ship yet.
>> 
>> Thanks,
>> Rick
>> W4GE
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