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I've made progress but it still isn't working right. I rewired T1 and reinstalled it. That fixed the loud tone but I caused more problems. I lifted a trace off the board from pin 4 of T1. It appears

There's some great advice in this thread and replacing IC6-9 sounds like a worthwhile mod, but I'm having a bit of trouble sourcing the TS922 in a DIP8 package.? They seem to have been discontinued

Great job on this video again Juddie with that CW switch plunger.? I did the same with mine, but I made my own plunger mod similar to yours.? I am interested now, in your "tilt up" stand that I can

I do not know if it helps, but I have encountered all sorts of resets ,frequency shift and blocking LCD with VFO signal generator transformed into TX WSPR in 28 and 14 Mhz. Now I'm feeding the three

Hi Alan, Academic?? ALL failures are an opportunity to learn and make a product more robust. I am surprised no one has talked about bringing up the power in steps? Measuring things as we go up to full

Hi Glenn, I'm in defence of all Hans views as well. /g/QRPLabs/message/26421 (I keep pointing out his statement that he has never experienced a failure of any prototypes and beyond to

Oops, sorry.? I meant Jim, not Ted? :-) 72 de Gary W0ITT

Ted - I had a similar experience.? Be sure you are using a stereo plug in the key jack.? The QCX *requires* one.? If you put in a mono plug it just keys the transmitter, and the tone you hear may

In defense of Hans, I don't recall seeing a brag about QCX able to handle infinite-SWR conditions. (ie: antenna short or open-circuit). ?I can see a dangerous scenario.... if you're using an

Hello Allison and Hans Many thanks for the detailed reply, I will take on board both yours and Hans' advice, much appreciated! Friday, August 24, 2018

The practice test was negative. My mistake: My tuner tunes to antenna voltage, no control of adaptation to the PA. This caused the PA to overload, causing the MPS2907 to burn. Repair ok. Change tuner

Alan, I don't know how Hans had no trouble although it could be that most QCX do survive abuse. Maybe only a few actually have problems? The design here

The LDG Z-100Plus requires only 0.1 watt to tune according to LDG and is rated for 125 watts which leads me to think that it has lower losses than some of the "QRP" tuners with much lower ratings.

Never a truer word said in jest, transistors being the fastest fuses on three legs..... Q1-3 & Q6 blown while protected by a F1A fuse, It does put things in perspective what a task it appears to be?

No, a more robust device will reequire a stronger driver device and likely a? revised DC feed.? ?The class E has fairly narrow bounds before it gets to a bad state.?? To protect it use a

So, in the midst of this discussion, if my finals blow is there a “drop in” replacement with similar characteristics but that will withstand considerably more abuse? 72, Charles - NK8O

Am 01.09.2018 um 20:07 schrieb Richard Harris via Groups.Io: Hi Richard, Thats a good idea. T1 should do it too with 3dB att - 2,5W. Using a 6db attenuator may cause the problem, that the tuner stops

That might confirm the saying that semiconductors blow fast in order to protect fuses from blowing... 73 Alan G4ZFQ

Len, I don't know why but the fuse settings do not seem to agree with Hans /g/QRPLabs/message/24845 73 alan G4ZFQ

The T1 is reported to tune with as little as 0.5 watts, and 2-5 watts recommended. Mine will tune even with repeated dashes. I haven’t run into problems with the QCX-20, but I am using an antenna