#QMX #Volatage #Transmit #Volatage #Transmit #qmx
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I have QRP-Labs build QMX mid-band Rev.4 f/w v_027 which is blowing finals. So far two sets, third set in.
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Transmitter Voltage is showing in RED to start with.
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Here are diagnostics screens
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After pressing "P", screen changes to this
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And after pressing "T" screen changes to this
?
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Off course all into dummy load.
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Calling few CQs into dummy load, I can see that finals get very warm and familiar smell is being emitted.
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As I said two sets of BS170 have been already smoked. Any pointers what to check.
Display SWR reading seem correct as well as output power.
?
Please help.
--------------------------------- 73 de Marek SP9TKW |
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In diagnostic mode the transmitter voltage should be very low, like .4 volts until you press T. It is red in the first image because it is way too high. The modulator transistor is either shorted or being forced on by some circuit fault.
Tony
AD0VC
From: [email protected] <[email protected]> on behalf of Marek SP9TKW via groups.io <sp9tkw@...>
Sent: Sunday, May 4, 2025 2:09 PM To: [email protected] <[email protected]> Subject: [QRPLabs] #QMX #Volatage #Transmit ?
I have QRP-Labs build QMX mid-band Rev.4 f/w v_027 which is blowing finals. So far two sets, third set in.
?
Transmitter Voltage is showing in RED to start with.
?
Here are diagnostics screens
?
?
After pressing "P", screen changes to this
?
And after pressing "T" screen changes to this
?
?
Off course all into dummy load.
?
Calling few CQs into dummy load, I can see that finals get very warm and familiar smell is being emitted.
?
As I said two sets of BS170 have been already smoked. Any pointers what to check.
Display SWR reading seem correct as well as output power.
?
Please help.
---------------------------------
73 de Marek SP9TKW |
Marek SP9TKW