Put everything back to normal EXCEPT IC4 then check resistance, if all ok replace IC4 (with a new one) and check again. If ok try powering up - what do you get?

If the regulator ic is overheating to the degree you say, I would assume that there is a short circuit somewhere. Better to try and trace the fault with a DVM before ripping things apart. QRP labs web

I would start by removing the agc module and set up the mini as is without the module. If you are still having problems with alignment I would suggest you check ALL the connections on the toroids part

That reply is pants!

Not true, solder can appear on both sides of the pcb but may not be in contact with the component lead, especially the coil windings.

Looking at the solder side of the board I spotted a few solder shorts + lots of suspicious joints. it is always easier to blame faulty components rather than faulty work.

And a lot of things a modern digital scope can do that an old analogue one can’t.

What prompted you to rewind the toroids?

#qcxmini

On the QCX mini there were one or two people who found that the BNC connector did not sit right on the pcb. The best way to sort the sockets on this edge of the pcb is to put them in place but NOT yet

I think most on here who have built the 40m version, have used number of turns as shown in manual and found `NO `need to alter the number of turns. After alignment I was getting about 2.5 to 3 w outpu

did you set the three trimmers at half way? don’t forget these trimmers are multi turn and you may have to adjust them for quite a few turns until something happens on the display.

#40m

Taken from the mini build manual:’- A Class-E power amplifier is a wonderful thing. It has a very high efficiency, sometimes over 90%. This has several important benefits: a) Since not much power is d

The metal washer is NOT the heatsink, the washer only serves to hold down the transistors on the PCB copper with IS the actual heat sink.

Instead of all the hoohah about QCX mini overheating of BS170’s, if you are going to use modes that have 100% duty cycle, why not run the mini on 9v, the power drop at the finals will not be noticed o

Because under normal conditions it is not required. There are lots of protection circuits but are they worth the effort. If things are built correctly there is no need for protection circuitry. Most c

sorry my friend, a fuse will not save you in the initial stages of powering up your construction. It MAY protect things once everything passes all the initial startup tests. Semiconductor devices/ic’s

IF there is a short circuit that caused the voltage regulator to fail then the following electronics MAY still be ok. PA4Q says he has replaced IC1 but things still not working leads to an obvious con

800ma current limit is far too high, I would set the limit as low as possible raising it gradually as you watch the voltage. With a very low current limit the voltage will drop to a very low value, if

Time and time again, this has to be repeated, BEFORE any attempt at powering up ANY self assembled electronics, you should perform simple checks with an Ohmeter, both on the 12v input AND the regulato

The truth hurts sometimes. When building any kind of electronic kit requires the builder to have some knowledge of fault finding and reading a schematic, without these you are on a hiding to nothing.