Sorry, Raduino feed by 10 ohms, not 100 - d'oh!

1. >12V to the BITX main board is likely to fry the LM386. They were designed to run as output with 9V battery power, and 12V capability was plenty overhead margin for that.
2. A good hefty reservoir (say 1000uF) on main board supply is pretty much mandatory. I feed this point with a 27-ohm resistor (gleaned? with the1000uF from a defunct PC power supply). The typically 130-170mA draw? of BITX and Arduino gives a few Volts drop, so even 15V to that is safe. Feed the PA Power from this point too - any hum or hash here won't affect power out too much.
3. A further reservoir (say 100uF) is recommended for the Raduino, fed by 100 ohms from main board supply. This decoupling will contribute significantly to reducing 'tuning clicks'.
4. RV1 fully CCW cuts the IRF off. They typically start drawing from about midway, and at that point it's touchy so care is needed to set ~100mA idle. If you've got a separate supply (say it's set >12V) I'd recommend its use for *this* (makes for a convenient current-measuring/monitoring point too).
5, RV136 fully CCW is max. drive. If you can't get full output at that setting, then you need a mic pre-amp. A simple 1-transistor stage should be sufficient, but you can go as fancy as you like ... :) My no-name PC headset's mic needs this. Yours might need a level/volume control - most Hams will have a scrap preset pot in the junk-box.

My BITX40 kit has fought me all the way, and despair is setting in. First assembly was 'al fresco', with long leads just stripped enough to solder where necessary or use clip leads. There was activity of a sort, but horrendous hash! OK, I thought, better clean up the wiring a bit.
Antenna BNC recommended less than 3" from board - done.
Speaker (and mic) - pairs twisted - a no-brainer, already done - check.
Volume and Tuning pots - better shield them. OK, that'll need Molex surgery. OK for the younger eyes and nimbler fingers, my efforts not up to par. Tuning pot soldered to the pins via some ex-CD audio lead (twin-ax). Similar Raduino output to DDS pins. Volume pot similarly twin-ax'd but left a bit of wire on the Molex plug to connect. Whew! Done. Molex less than 100% stable, move 'em a bit they crackle.
Decoupling power supplies improved things a little, largely subduing tuning clicks from the Raduino.
Still horrendous static, but glimpses of an occasional carrier. AM on 40? That'd be a rarity! Commercial intruders? no band-chart, HF's terra incognita to me. What's up here?
Brought in (read:unearthed) my trusty old Leader SG-11 sig.gen, verified by sweep I'm hearing somewhere just above 7MHz, and sensitive enough to clearly detect on low output setting, control turned to minimum and output lead shorted - case-leakage radiation. Good enough for me, why no voices? There's a fair amount of wire about gutter-height, a guesswork OCF - should be hearing mid-ZL at least.
Farmed in a NiCd battery from a long-unused drill, while that was being charged the static reduced enough to discern faint 'donald-duck' voices. Is the BFO on the proper (high) side of the filter? No way to tell, professional assistance required. Long time away from nearest active Club (ZL2KO), and having nearly shaken of the seasonal Cold I'm destined for Rest-home 'respite', so it'll have to wait.

thanks John....not sure what I was thinking.? I'll just pair some up for the voltage. 2 caps in parallel, then put those in series with another parallel set will give me 100pF/200v. The parts are small enough not look to ugly ;)

it is both Double and Triple checked NO short !
I do not belive cw-sidetone mods can give that problem since I have tried with another speaker !
speaker plug was removed yesterday evening when I tested with earphone PIN 5 on LM386 gives audio but connect to speaker plug gives no audio, and only part between this 2 points is C111

Looks like RF got into your arduino board.

I suspect your RF termination is not proper even though you stated you are using a dummy load.
I was doing the same but had RF all over, found later that the braid of the BNC to load was frayed.
After I replaced it all problems vanished!

At 15/07/2017, you wrote:

Let me back up again:

My kit came with something like 1.0 or 1.1 already installed on the nano. Right out of the box my Bitx would receive fine but not transmit. While I was waiting to try and resolve the transmit issue I uploaded 1.18 to the nano and used the radio on receive for a few days while I asked some questions. Someone mentioned that the RV1 and R136 would increase the output if turned to the left rather than turned to the right. I had only been moving them from what appeared to be near the center position to the right. So I put a dummy load/power meter on it the other night and instead of using the 12v 1.5a wall wort supply that I had been using I switched to my Samlex 13.8v power supply. I turned to power on to the power supply. Plugged the radio in and turned the radio on. I keyed up and was watching my power meter and speaking into the mic to see if adjusting either pot would give me some kind of output. While I was doing that I just hapoened to look at the display and noticed that it w

as still lot up buy I had black squares across the top row of the display and no longer any text. I powered the radio back down and up again and the display stayed that way. So I thought maybe something happened and the Arduino lost its mind. I unplugged the radio from the power supply and decided to see if I could upload to the Arduino. I could not. I unsoldered the Arduino tonight and noticed that C17 looks like it had disintegrated from the board. So I have some new Arduino coming on Sunday.

namaste, Sarma raj

Your suggestion may be good, but the first thing told to a ham should be look in old pieces of equipment for something.
Or go to a hamfest and see what 's there. Or the junkbox. (It doesn't take long to get one of those). The real problem is finding something...Hi.

The second thing is to take two 50v caps of 200 pf, and put them in series. That would give 100 pf at 100v. It works. And probably the voltage
rating is not too critical at QRP levels anyway. The important thing is to use npo caps (rather than X7V or something similar).

I am sure I can find something for Paul (like a 100 pf. SM cap), but unfortunately not right now as my shack is in a mess with re-tiling, re-painting and such...
It would be a simple matter to find something, slip it into a padded envelope, and send it on. I am sure one of us here in W land can do that...


john
AD5YE

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I always wanted one of those. I called for about an hour but with some random AM stations and some other 1KWers I stopped after a while.

?Just wish my CQ times were better, I am dealing with some bad RFI 12 hours a day and kids goto bed soon after the RFI stops for the day.

?

Will be on again tomorrow night around 7:30 pm est

?

Let me back up again:

My kit came with something like 1.0 or 1.1 already installed on the nano. Right out of the box my Bitx would receive fine but not transmit. While I was waiting to try and resolve the transmit issue I uploaded 1.18 to the nano and used the radio on receive for a few days while I asked some questions. Someone mentioned that the RV1 and R136 would increase the output if turned to the left rather than turned to the right. I had only been moving them from what appeared to be near the center position to the right. So I put a dummy load/power meter on it the other night and instead of using the 12v 1.5a wall wort supply that I had been using I switched to my Samlex 13.8v power supply. I turned to power on to the power supply. Plugged the radio in and turned the radio on. ?I keyed up and was watching my power meter and speaking into the mic to see if adjusting either pot would give me some kind of output. While I was doing that I just hapoened to look at the display and noticed that it was still lot up buy I had black squares across the top row of the display and no longer any text. I powered the radio back down and up again and the display stayed that way. So I thought maybe something happened and the Arduino lost its mind. I unplugged the radio from the power supply and decided to see if I could upload to the Arduino. I could not. I unsoldered the Arduino tonight and noticed that C17 looks like it had disintegrated from the board. So I have some new Arduino coming on Sunday.?

Unlikely C111 but you may have a short in your speaker jack/socket or wiring.

Raj

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I believe I did that before I downloaded 1.18 into the nano. I'm guessing that if I didn't install those drivers I wouldn't have been able to download?