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Re: #qmx QMX and waste heat from the finals #qmx


 

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Wayne,

There is just a hole through the plate to hold it in place and a foot that you can't see almost at the left hand edge under the plate the same as the one that is visible on the right hand side. It was made from a piece of aluminum molding that happened to have those two feet in the right place. I may try to put a piece of it under the finals on the QMX, but without the feet, as I'm sure there isn't enough room for the extra height of the feet.

I also added the diode across L14 so hopefully it will be as bullet proof as I can make it and baring operator "destructive" testing should last a long time.

Here's the reference from John Z to the diode "fix" in case you are interested.

The diode simply is in parallel with the 47uH inductor L14, with the
orientation shown in the photo provided by Paul W9AC. Cathode towards
the power supply connection, anode to the transformer center tap.
Any of the diodes he mentioned ?(1N4448, 1N4148, 1N914) will do a fine
job of absorbing the end-of-transmission voltage spike it produces.
I have used a 1N914.

/g/QRPLabs/message/105256

73,
Cliff, AE5ZA



On Aug 30, 2023, at 09:35, Wayne Greene <wayne.greene489@...> wrote:

Hey, Cliff. How did you mount the plate under your finals?

Wayne KB4DSF

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