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Yep I think I did it. I applied reverse polarity to my BITX40 from HFSignals. The power to the board was connected but no power to the PA. (The connector I used had the positive connected to the outside and the negative to the central - was for an odd piece of test gear I used years ago). Anyway, correcting the connector results in no sign of life on the display. Reading through the posts, it would appear that I may well have bricked the raduino. Hence I would like to contact Mike Hagen to enquired about his improved raduino. So could Mike please contact me off list so we can discuss features, costs etc. And the irony is that components toprotect against reverse polarity are on order but have not yet arrived. vivimus atque discimus.

Looks the L and C formed a series resonant circuit at the transmitted frequency.

make that K1 Rec. pin3=0 volts sorry 73's de AC8XZ

From the photo, looks like a burned trace from C6 to L3.
From the Bitx40 schematic it's hard to imagine how that might have happened.

ok how about these readings; K1 Rec. pin1=0volts pin3=12volts pin5=12 volts pin =8 12 volts pin9=12 volts pin12=0volts pin14=0volts pin16=0 volts K1 Trans pin1=12 pin3=0volts pin5=12volts pin8=12volts pin9=0volts pin12=0volts pin14=0volts pin16=0 volts K3 Trans. pin1=0 volts pin3=0 volts pin5=0 volts pin8=12 volts pin9=0 volts pin12=0 volts pin12=0 volts pin14=0 volts pin16=0 volts KT1 Trans. pin1=0 volts pin3=0 volts pin5=0 volts pin8=12 volts pin9=0 volts pin12=0 volts pin14=0 volts pin16=0 volts KT2 Trans. pin1=0 volts pin3=0 volts pin5=0 volts pin8=12 volts pin9=0 volts pin12=0 volts pin14=0 volts pin16=0 volts KT3 Trans. pin1=0 volts pin3=0 volts pin5=0 volts pin8=12 volts pin9=0 volts pin12=0 volts pin14=0 volts pin16=0 volts. VOM Black to Antenna Ground Red to pin being tested. hope this is good readings 73's de AC8XZ

From the photo, looks like a burned trace from C6 to L3.
From the Bitx40 schematic it's hard to imagine how that might have happened

Do let us know what parts had to be replaced once you get this fixed.
And any guesses as to how it happened.
For me at least, truly a mystery.

Jerry, KE7ER

I use a 13.5 , 2 amp power source instead of 12 volts lead-acid battery, like in shown voltages chart.
Remeasured voltages are:
Q13: collector 13.34 v, base 4.21 v, emmitter 3.57 v
As i see they are practically the same as in voltage chart.

I am putting black lead of vom on ground (black wire of the power connection and red lead of vom on the pin I am measuring. Is this correct? The square pin 1is [] ok you said go clockwise counting so the pin under pin1 is next pin to count. Than at bottom of that row cross over to next row at bottom and that should be next pin to start counting. Am I correct. I will try today again to measure voltage again. Thanks for your help. 73抯 de AC8XZ

I have a trouble with BITX40 kit from HFSignals.
Receiver work great - i hear a lot of stations all over the world. But there are no transmission when pressing PTT.
I check currencies al described in instruction (both main board power and PA power connected):
In receive mode current is 136 mA
When press PTT - 330 mA
If saying HAAAAALO to microphone when PTT pressed - the current still 330 mA and not changed.
I try to adjust PA as described in instrunction - connect ammeter directly to PA power line. First step is adjust VR1 to PA currency 100 mA. It is ok. Second step - saying HAAAALO microphone - fail, PA currency still 100 mA and not changes. I try to change value of VR136 - PA currency changes a little.
Also i try to check microphone amplifier - i connect external LM386 amp board to negative pin of C122 capacitor. When pushing PTT and saying anything do microphone - hear me from external amplifier, it means that mic amp works ok.
At the next step i connect an external continuous wave oscillator worked at 7.100 Mhz to input of PA - left pin of C132. The PA currency raise to 1 A and there is a CW output in antenna. It means that PA works.
At the next i connect continuous wave oscillator worked at 7.100 Mhz to to the right end of C43. The PA currency raise to more than 1 A and there is a CW output in antenna. It means that preamp Q4 also works.
I have no ideas what to check more with my equipment - i have no oscilloscope, have only digital multimeter, frequency meter (up to 70 Mhz), and a continuous wave oscillator (up to 70 Mhz).