John,
I think it may be the other way around, actually.
The reference voltage for the 5,5V smps control loop is the 3.3V smps output.
If the 3.3V output goes too high, the 5.5V smps will do so as well.
JZ
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On Tue, Oct 17, 2023 at 9:21?AM John N0TA <reillyjf@...> wrote:
I received two new power supply boards from QRP Labs yesterday, and QMX appears to be working. I initially had the Q103/104 problem, and never managed to successfully repair the boards.
What I don't understand is how the failure of the 5v board causes the failure of the 3.3v board. Be extremely interested if someone could explain that.
I submitted a ticket to QRP Labs and several updates, but never got a response from them. Guess receiving the boards was response enough!
- John, N0TA
