[Elecraft] KX1 LOST TX NEED HELP PLEASE

[Don Wilhelm]

Mike,

Q6 Emitter should be grounded and should have no RF voltage on it.
If you have the collector and emitter swapped (collector is the center 
lead) even then, that is not enough RF voltage on either the collector 
or the base.

Start at the source of Q1 where you should have about 160mV rms or more.
The collector of Q4 and the base of Q5 should have about 800mV rms.
The collector of Q5 (T1 lead 1) should have about 5 volts rms.
The base of Q6 should have about 3.2 volts rms.
The collector if Q6 should have about 20 volts RMS.

Make sure the DC voltages are reasonable first (see the schematic).
Do NOT transmit without a heatsink on Q6 (insulate the tab with the 
thermal pad.

73,
Don W3FPR

On 5/6/2017 11:43 AM, michael warrington wrote:
> KX1 STILL NO TX! Help Please.
> Still can't work out where my TX fault is, I have a tiny amount of RF at the antenna out.
> 
> A Few measurements made using an RF probe and dc voltmeter
> At T1      Pin1  5 volts
>                  Pin2  0 volts
>                  Pin3 0 volts
>                  Pin4 1.9 volts
> 
> Q6          Base 1.9 volts
>                  Collector 0 volts
>                  Emitter 1.8 volts
> DC voltages seem about right, tried lots of stuff remove rewind T1 replaced q4 q5 q6.
> Anyone who can help guide me where to look with the RF probe to narrow the problem down a bit,
> I don't seem to have enough knowledge to move forward.