Re: Went Dead

Ralph Mowery
 

While they cost close to $ 5 each  you may want to look at replacing the outputs with some RD16HHF1.  One good thing is the tab is at ground so you can bolt it directly to a heat sink.  You will have to cross two of the leads as the pinout is slightly different.  I did this and put a very large heat sink on mine to handle the extra heat from doing other mods to get the power up on some of the bands.

de ku4pt


On Sat, Jun 16, 2018 at 12:09 PM, Bill Watkins <kf7yxs@...> wrote:
Absolutely right about using a new plan and your’s and other’s suggestions!

Have to think through the new heat sink . .  Maybe leave wspr to qrp labs qcx for now; purposely built for that.  I have a qrp labs US3 on the bench. Those two will do all the wspr I need. I’ll leave the ubitx for cw and phone. 

 Have to get it transmitting again first.  Will definitely pay attention to the list guidance for replacing the mosfet. 

Was definitely good feeling to have that qrp chat on it right out of the box. Really like this radio. Fan already installed in the new enclosure. It’s a computer type; probably not enough. 

Bill




On Jun 16, 2018, at 08:40, Doug W <dougwilner@...> wrote:

If you are using WSJT-X for WSPR there is a tx% setting.  At 100% it sends every time cycle, lower less.  I still wouldn't tx WSPR without a plan to remove the heat but a lower tx% will also give the MOSFETS a much needed break.

If you need some tips for removing the IRF510's from the board search this list it happens often enough.
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