Problem with 6500 KPA500 kat500 power out only 300w

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  • Updated 7 months ago
I can only get 300w out using the above combination.
I've connected to TX1 on 6500 to the KPA500.
Changing max power above 35 - 40w drive doesn't make any difference!
Anyone any ideas where to look
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Ken Chandler

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Posted 8 months ago

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WX7Y

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sounds like you may have lost one of the Mosfet Power transistors in the AMP.
Best not to push it and blow the other one. 
May need a trip to the shop if you don't have a way to repair it.


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Ken Chandler

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Thanks, never thought of that, been running it with my K3 changed it to the 6500 today for the first time!!!
I thought I could be ALC holding it back but no alc on the flex!!
Ken
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bahillen

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Try the K3 again
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Ken Chandler

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Weird or what! Hooked my K3 back up 30w drive and I'm getting the full spec power output..
If anyone can help I'd be grateful if you can post!
Ken
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K3SF

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hi chandler

see what power the flex 6500 is actually putting out.
and
if the radio full duplex mode maybe an issue of receiver overload cutting back the power out from the flex.

i have seen this happen with my 6600M which has two scu.
and
yes, i know the 6500 only has one scu
but i
think it is function also of full duplex.

in my case the second scu was on another antenna and was going into overload and the radio cut back rf output to my kpa500....

i also thought i blew my amp until i realize my configuration caused the flex to cutback on rf output to protect the second scu.

Paul K3SF
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Erik Mellgren

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What mode are you using? I have a 6400 and the output is very sensitive to the setting of the DAX channel TX Gain. The Flex 6400 is using the DAX channel for digital modes AFSK when controlling from SmartSDR. Similar for the 6500?

Erik SM0JCA
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Greg - N8GD

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ATU turned ON and/or not in Bypass mode?  Some amps don't do well trying to tune their input with the ATU in the XCVR.
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bahillen

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Is it the same into a dummy load?

Could eliminate some possibilities.

I recall somewhere that ALC is not recommended with the flex.