Anybody effected, see if this helps? https://groups.io/g/QRPLabs/message/22418 I suspect Han's has being sidetracked to have rewritten that section into the build manuals so

I had problems with my second kit, I couldn.t make any adjustment on the last 2 adjustment steps, turns out R27 was defective, when I plugged in the headphones and turned R27 I either had tone or

James W4JED, if it's not too late, before you discover it the hard way... The kit designer has implemented a gotcha to discourage unauthorised copies of the QCX being built.

Thanks Hans for clearing up the module's behavior when 'out of circuit.' As I alluded to in the other thread I mistakenly created, the module is currently working and my U3S has been running overnight

All correct, Daniel FYI the standard Si5351A-B-GTR does nothing on power-up, no clock outputs. It requires programming via I2C to make it do anything. Custom versions are possible, which have default

Al, The "Subject" line is the topic. Add to it, or change it produces a new topic. (Unless there is a way to add something without changing the topic?) 73 Alan G4ZFQ

I was about to ask about whether the tuning for the 60m QCX was channelized, as I couldn't find anything in the group message archives. Then I thought to look at the Assembly manual. It indicates that

No one else has had low readings on the bpd peaking step? ...begining to make me think I have something seriously wrong.

sorry, I hate it when it starts a new topic!

It's working again!!! I reheated connections, header pins, removed rosin and gave it another close inspection and plugged it back into my U3S. And, to paraphrase a Huey Lewis & News song, ".....the

Al, Sorry. Missed your earlier post which said you were seeing the Flash Screen on bootup without the synth. David

I've given the board a close review and there's not much I can tell with the board out of circuit. My oscilloscope (Tek T922) does show high frequency signal on the crystal pins so I'll assume it's

Just to be clear: The change that I am proposing would 'copy' the current "11 Band LPF" addition that is documented and used on the U3S today (11-band U3). 11-band U3 hans summers qrp-labs.com The

If the synth module is not even plugged in you still get text -- "QRP Labs U3S ver 3.12 etc....."until an error message is shown.

If I'm not mistaken, the lcd display is initialized before the mcu even speaks to the synth over i2c. So the two rows should disappear (and probably display text) before the i2c synth stuff begins. So

I ordered the display suggested above by Alan - W3AL. Fixed the problem. Thanks Alan. 73 de Andy W4KIL

Thanks Daniel, I'll look into it. Are you saying if the 27MHz crystal is not oscillating it will not prevent the synth module from keeping the U3S from initializing? (Is that a double negative? :-)

The 27MHz crystal has nothing to do with the mcu, so the boxes tells you that the lcd is not initialized. It requires a certain sequence from the mcu to start up and clear. One pin is shared between

Basic problem with the request is that it doesn't contain a suggestion on how the hardware should work. I'ts certainly not impossible, just that it has no simple solution that doesn't have the risk of

Hi Eamon The correct diagnosis of the problem and the correct solution is described here http://qrp-labs.com/qcx/qcxmods.html#pwrup (change inductor position). The capacitor helps attenuate any