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the board . . . If you are going to save the part, just clip the leads and unsolder the part one lead at a time. >

Thanks Stan. Let me clarify a couple points. Correction of my statement: At the drain of Q109 is the PWM'd square wave that alternates between 11.9 and 10v. On the other side of the filter at the

If you are worried about series inductance of resistors, best to build a 50 ohm dummy load of all parallel resistors.? ?Not a series combination of two sets of two 50 ohm resistors in

This might need clarification for some: Lifting one end of a resistor or cap or diode can rip the opposite pad off the board. That will ruin your day. Usually easy enough to repair by running a wire

I have to correct. Checking my repair records I found one case with a broken IC403, not clear why broken. 73 Ludwig

Donald, you are right. It#s good to tell this. I'm doing this only for some SMT packages e.g. small diodes (SOD323), small transistors (SOT23) and some tantalum capacitors (yellow). All of these have

Hi Keith, Have you tried any of the suggestions on the QCX troubleshooting page? https://qrp-labs.com/qcx/qcxtrouble There is also a YouTube video by Hans on the

Adding Chris's BAT41 and 0.1uF cap to read the peak voltage with a DVM is a good idea, will work great for a QMX. Han's 20W dummy load does the same, but uses a 1n4004 diode, good for 400 Volts,

Hi Ronald Many thanks for your reply. I have tried adjusting all the low pass filter windings and have taken 0ne turn off each toroid. At first I could only get 1 watt out and after adjusting the

Joerg, you have mail. 73 Ludwig

The groups.io forum clips any email addresses so they don't get harvested by purveyors of spam. Say it in words if you wish to make it public, such as "j doe at Gmail dot com" Know that the email

Email: mordan42@... ( mordan42@... ) Apologies

Please add me to group buy for v2 when it's solidified. Mordan42@.... thanks!!!! 73 de AD5MO

Daniel, Without the SMPS boards, I measure a resistance of only 250 ohms on the mainboard between PWR_HOLD and GND. PWR_HOLD is connected only to pin 53 of the processor. I therefore conclude that

This one has a QRP focus. https://www.qrparci.org/resource/FDIM81.pdf Ed AB8DF

Hello, Yesterday I make a QSO with the internal mic. I see we need another external mic. But it's possible to remove internal mic (I mean "desolder"), but install another good mic at this same

Paul, NA5N, has a good summary here. https://www.rmham.org/wp-content/uploads/2023/03/4_NA5N_Solar-Propagation-Companion.pdf

Joerg, No, that doesn't sound good, but as long as the main processor is good, it's worth fixing. If you can identify the failures. It looks as if the failure on the 5V PS took out the 3.3 V supply

My dummy load uses 4 x 51R 2W SMD resistors connected in series parallel, then 2k5 to 2 x 100R to give a dummy load come 40dB attenuator.? It also has a BAT41 Schottky diode and 0.1 uF capacitor to

Hi, I'm using a gaming headset with build in mic. I found that the mic wasn't sensitive enough as I had to set the mic gain on my QMX so high that it started to produce undesirable background