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#bitx40help #bitx40
#bitx40help
#bitx40
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I am very new to homebrew electronics and was thrilled when I built a working Bitx40 right off the bat.? I did several mods and tested each one along the way.? I was feeling quite confident.? I upgraded to raduino_v1.28.1 and installed the Function Button, PTT, CW carrier all without issue.? As I am learning Morse I really wanted to add CW.? Something happened when adding RX-TX or the straight key and my radio no longer receives.? If I press the PTT button, it sounds like it is transmitting so my uneducated guess is that the Raduino is broken.? No display on LCD (Does light when PTT is pressed), no? tuning clicks no receive audio other than a hiss.? It really was the last step before I found a case for the radio.? I ordered a new kit, but I don¡¯t know exactly what I did to break the device.? I do know that I wired the RX-TX WITHOUT the ptt button.? The straight key I wired to the raduino and then to the main ground.? I am not 100% sure If I did both of these mods at the same time or not.? Can anyone show a picture or describe their RX-TX and Straight Key wiring?? I want to rebuild, but do not want to make the same mistake twice. |
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Brian,
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I'd guess the Arduino Nano died. Can you still upload new firmware to the Nano? The good news is that they cost as little as 3 dollars, and are socketed on the Raduino to be easily replaced (since mid 2018). Do you have a scope? You might check to see if CLK2 into the DDS1 connector has a proper VFO signal, should be around 4.8mhz. Alternately, listen for a 4.8mhz carrier on a nearby shortwave receiver. (Could be off by a couple hundred khz, depends on the operating freq saved to EEPROM.) If the 4.8mhz VFO is there, then the Nano is at least doing something. The wiring harnesses on the Bitx40 have a bunch of wires flying around loose. Some of those wires are quite dangerous, such as the loose wire from the Raduino that has 12v on it. If the end of such a wire touches the wrong thing, it can destroy the Nano (or something else). Best to either tape over the ends of those wires, or remove the wire from the connector by pressing the retaining clip at the connector with a sharp tool while tugging lightly at the wire. The Nano clones being so cheap, some simply fail due to poor quality control. For example, some of the Nano's work, but draw 10x the supply current that they should.? For a while. The wiring instructions and diagrams that Allard provides ? ?? are pretty good.? I don't think I could describe that wiring any better. Jerry, KE7ER On Wed, Apr 3, 2019 at 08:03 AM, <hockeydad42@...> wrote:
Something happened when adding RX-TX or the straight key and my radio no longer receives.? If I press the PTT button, it sounds like it is transmitting so my uneducated guess is that the Raduino is broken.? No display on LCD (Does light when PTT is pressed), no? tuning clicks no receive audio other than a hiss.? |
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Thanks for the reply Jerry!! I do not have a scope or really the in depth knowledge to use one.? I did try to upload the firmware back to the raduino and that was successful.I guess there is no harm in me trying to replace the arduino, I don't think I can break it any more than it already is.? I just wish I knew exactly what I did to cause the issue so I dont do it again.? would wiring the TX RX without the button have caused the problem?? I re wired that part with the button - Currently I have the black and brown wire from the PTT jack on the board going to the switch, then I have a black and brown wiring going to the outside pins of the transistor, the middle wire goes to a 4k7 resistor and to the raduino pin.? ?I was pretty happy that I pulled of the build without destorying it until the last step so I dont want to destroy another one LOL
Brian |
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Brian,
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Allard's suggested wiring for the TX-RX wiring looks pretty safe: It provides a way for the D7 pin from the Nano (mounted on the Raduino board)? to energize a relay coil.? Since D7 is isolated from everything else by a 4.7k resistor, even if that NPN transistor was destroyed to where 12v was shorted to the transistor base, the worst that the Nano would see is 12v/4.7k = 2.5ma, which the IO cell protection diodes inside the processor should be able to easily handle. You did at least have the 4.7k resistor wired up correctly, right? I suspect the dead Nano is unrelated to the TX-RX mod.? On a properly working Raduino (with the LCD display and Nano processor plugged into it), just plugging the Raduino's USB port into a USB power supply (or a host computer USB port) should power up the Raduino and put something on the display.? No other cables required, no need to connect anything from Raduino to the main Bitx40 board So I would debug this problem without the main Bitx40 board present.? >? No display on LCD (Does light when PTT is pressed),? This is weird.? The LCD should be lit and show characters on the display whether or not PTT is pressed. I suggest you use a voltmeter if you have one to look for 5v coming out of the big MC7805CT three?pin voltage regulator hanging off the side of the Raduino. The holes in each corner are a safe ground to attach the black lead of the voltmeter. Use the red lead of the voltmeter to measure the voltage of the right most pin when holding the board such that "MC7805CT" is rightside up.? Should be around 5 volts. Also curious that you can load firmware into the Nano, but the LCD display does not work. It does seem that the Nano is mostly working. If you get a new Nano, be sure to buy one that does not have the header pins already soldered in place. The Raduino needs to have those pins soldered to the other side of the Nano than normal people have it. Here's a possible source: ? ??? ?? A cheap voltmeter can be had at Harbor Freight if you don't already have one. Sometimes free with a purchase of something else, often a dollar or two on sale, regular price of maybe $5. If you get stumped, perhaps find a local amateur radio club.? Bring your meter and Bitx40 schematic, see if somebody there can be interested in looking the Raduino over with you.?? Jerry, KE7ER ? On Wed, Apr 3, 2019 at 09:01 AM, <hockeydad42@...> wrote:
Thanks for the reply Jerry!! I do not have a scope or really the in depth knowledge to use one.? I did try to upload the firmware back to the raduino and that was successful.I guess there is no harm in me trying to replace the arduino, I don't think I can break it any more than it already is.? I just wish I knew exactly what I did to cause the issue so I dont do it again.? would wiring the TX RX without the button have caused the problem?? I re wired that part with the button - Currently I have the black and brown wire from the PTT jack on the board going to the switch, then I have a black and brown wiring going to the outside pins of the transistor, the middle wire goes to a 4k7 resistor and to the raduino pin.? ?I was pretty happy that I pulled of the build without destorying it until the last step so I dont want to destroy another one LOL |
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When powering the Raduino from a USB port, that right side MC7805CT pin should be whatever
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the USB port is giving it, likely a quarter volt below 5v due to a protection diode on the Nano. When powering the Raduino from the main Bitx40 (or uBitx) board, we have 12v going? into the left side pin of the MC7805CT, and if that voltage regulator is doing its job then the right side pin will again be around 5v, but this time the power is not from the USB port. If you plug a powered USB cable into the Raduino while the Raduino is wired up? to an unpowered BItx40 (or uBitx), the MC7805CT will allow some of that USB power through to the radio, enough to allow the receiver to sort of work.? Hasn't created a problem yet, though the load on that USB power source can be significant. Especially if the rig then tries to transmit for some reason. A 1n400* series diode (1n4007 or similar) in series with the 12v lead from the Bitx40/uBitx into the Raduino would prevent this back-current when the Raduino's power is supplied from a USB port. Such a diode would also protect the Raduino in the event that the 12v power supply is reversed, and reduce the amount of power (slightly) that the MC7805CT must dissipate.? All good things. I would mount that new diode on the Raduino board itself, after cutting the obvious trace? between P3 pin 16 (on the end) and the MC7805CT pin 1 (on the left side). Jerry, KE7ER On Wed, Apr 3, 2019 at 11:23 AM, Jerry Gaffke wrote: Use the red lead of the voltmeter to measure the voltage of the right most pin |
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Thanks, yes I did use the 4k7 resistor on the Tx rx mod.? I will troubleshoot the nano a little more tonight.? If I just power it on with USB - What would normally be on the display?? I assume if nothing or it misbehaves, then it is for sure the nano.? i did try another LCD that I had with an old arduino Kit.? Same exact behavior also, no receiving so I was sure it wasnt just the LCD. Thanks for the link - I ordered a nano without pins attached from Amazon.? It is a shame I have 2 nano's at home with the traditional pin arrangement.? THANK YOU!!!!? What about the straight Keyer connected to the Nano with a 1k resistor and the other wire to main ground?? Could that have done something?
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When just powering up the Raduino without the Bitx40, the LCD should show something that looks intelligent.
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Could be a setup screen, could show the freq at which it is trying to receive, could be trying to transmit. But will be readable characters and numbers if it's working, not a blank LCD. What it does depends on your particular firmware, and may depend on where some IO pin happens to float to. The CW-Carrier mod involves driving the Bitx40 modulator through a series 4.7k resistor from the Nano's D6. That doesn't look dangerous to me either, for the same reasons that the TX-RX mod looks safe. All of Allard's Bitx40 mods should be plenty safe if performed as instructed, many have been built. Most blown Bitx40's were due to an unused wire scraping across a part, or accidentally grounding the IRF510 heatsink, or reversed power supply leads, or too high of a power supply voltage.? (I would not go over 12.5v on the Bitx40) A single cold solder joint between the Nano and the LCD display could do this. Inspect the Raduino especially, also the Nano and display, with good light and strong reading glasses. A cold solder joint would explain why it worked before, and now it does not for apparently no reason. You might try pressing and wiggling boards and connectors on the Raduino while somebody else repeatedly powers up the Raduino through the USB port. The Raduino probably tries to write something to the LCD at reset (power up), then hangs around waiting for you to tell it to do something.? So the LCD may only get written to at power up, and it's not enough to just push connectors around while it is already powered up. Jerry, KE7ER On Wed, Apr 3, 2019 at 01:57 PM, <hockeydad42@...> wrote:
Thanks, yes I did use the 4k7 resistor on the Tx rx mod.? I will troubleshoot the nano a little more tonight.? If I just power it on with USB - What would normally be on the display?? I assume if nothing or it misbehaves, then it is for sure the nano.? i did try another LCD that I had with an old arduino Kit.? Same exact behavior also, no receiving so I was sure it wasnt just the LCD. Thanks for the link - I ordered a nano without pins attached from Amazon.? It is a shame I have 2 nano's at home with the traditional pin arrangement.? THANK YOU!!!!? What about the straight Keyer connected to the Nano with a 1k resistor and the other wire to main ground?? Could that have done something? |
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Troubleshooting just got a little more interesting.? I connected Raduino to PC and it behaved like it was suggested here.? For some reason the LCD brighness was set at 100%,? I connected it back to the bitx40 board witht he same behavior.? I tried running it with a USB cable powering Arduino and it all looked normal , but no receiving.? I connected the usb AND the power from the board and it seems to work.? I am not sure what I need to do now.? But I am much further than I was, though still far away from understnding what happened.
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> I connected it back to the bitx40 board witht he same behavior. Be specific.? I'll? assume it was behaving badly, with nothing on the LCD. > I tried running it with a USB cable powering Arduino and it all looked normal, but no receiving.?,? So what's "normal"?? I assume the LCD now shows the receive frequency, but you can't hear any stations > I connected the usb AND the power from the board and it seems to work. Exactly what works?? Do you now hear stations? If you have the Raduino properly wired up to the Bitx40 and the LCD only comes alive when you also cable up the USB port, that means the Raduino is not getting powered from the BItx40. First thing, I'd turn off power, verify that there is a good ground connection between the Bitx40 board and the Raduino?by measuring zero ohms between the ground planes on those two boards. Could be that 12v is not going from Bitx40 to Raduino due to a wiring or connector problem. Could be that the 12v is not getting regulated down to 5v by the 3 pin 7805 regulator. Check for both of these by measuring voltages at the 7805 pins as described in my previous post. I'm guessing the trouble is in how you implemented step 3 of the wire up instructions:?? ? ? where it says:
Troubleshooting just got a little more interesting.? I connected Raduino to PC and it behaved like it was suggested here.? For some reason the LCD brighness was set at 100%,? I connected it back to the bitx40 board witht he same behavior.? I tried running it with a USB cable powering Arduino and it all looked normal , but no receiving.? I connected the usb AND the power from the board and it seems to work.? I am not sure what I need to do now.? But I am much further than I was, though still far away from understnding what happened. |
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?I goofed slightly when I connected a ten turn pot for my Raduino. ?Got two wires reversed, so I have to swap em ?Not really a problem, because I merely tacked the wire ends to the lugs on the pot. ?It does work as it is, but going by the display, in reverse, and maybe a bit touchy. ?LOL ?Wayne WA2YNE ?Even us old timers can make errors. |
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Lots of good info here for me to absorb.? Thank you Jerry for helping me get this far.? Let me clarify what I have learned so far
With the raduino and the Function button, PTT, Straight Key, CW Tx RX and Carrier modifications wired appropriately with the recommended resistors and transistor,? when the bitx is powered on no characters appear on the LCD and there is no receiving of signals or stations.? The LCD in this scenario is dark, unless I press PTT, then it lights up and I hear an audible power click from the bitx40 board - which I believe is normal on transmit. If I unplug the power wires from the center of the Bitx40 board that run to the Arduiino AND plug a powered USB cable to the Arduino, the LCD and the Arduino functions, meaning I can tune and see freq changes, i can use the function button etc.? There are NO stations or signals received. IF and only if I plug both the powered USB to the Arduino AND the power wires to the BITX40 board, the radio functions, and I mean all functionality.? Receiving signals and stations, function button USB, LSB, CW etc.? The straight key also seems to function - when pressed I hear the beep and TX is locked so you cant use ptt when using CW.? Also with USB and board power plugged in the annoying clicking during frequency tuning is completely gone and received audio is louder.?? I will go through the rest of your suggestions, I just wanted to clarify where everything was as of now.? Again - THANK YOU for the help! It is a power related issue to the arduino, but it seems there is power enough to light up the LCD when PTT is pressed. |
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Brian,
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The regulator is a big 3 pin TO220 part hanging off the side of the Raduino. The display and the Arduino Nano clone plug into the Raduino. These 3 previous posts are all talking about how to go about looking at that regulator: From post? ?/g/BITX20/message/67507 The LCD should be lit and show characters on the display whether or not PTT is pressed. I suggest you use a voltmeter if you have one to look for 5v coming out of the big MC7805CT three?pin voltage regulator hanging off the side of the Raduino. The holes in each corner are a safe ground to attach the black lead of the voltmeter. Use the red lead of the voltmeter to measure the voltage of the right most pin when holding the board such that "MC7805CT" is rightside up.? Should be around 5 volts. From post??/g/BITX20/message/67509 When powering the Raduino from a USB port, that right side MC7805CT pin should be whatever the USB port is giving it, likely a quarter volt below 5v due to a protection diode on the Nano. When powering the Raduino from the main Bitx40 (or uBitx) board, we have 12v going? into the left side pin of the MC7805CT, and if that voltage regulator is doing its job then the right side pin will again be around 5v, but this time the power is not from the USB port. /g/BITX20/message/67524 If you have the Raduino properly wired up to the Bitx40 and the LCD only comes alive when you also cable up the USB port, that means the Raduino is not getting powered from the BItx40. First thing, I'd turn off power, verify that there is a good ground connection between the Bitx40 board? and the Raduino?by measuring zero ohms between the ground planes on those two boards. Could be that 12v is not going from Bitx40 to Raduino due to a wiring or connector problem. Could be that the 12v is not getting regulated down to 5v by the 3 pin 7805 regulator. Check for both of these by measuring voltages at the 7805 pins as described in my previous post. I'm guessing the trouble is in how you implemented step 3 of the wire up instructions:?? ? ?? where it says:
On Thu, Apr 4, 2019 at 08:32 AM, <hockeydad42@...> wrote:
Ok thanks I will check that, but first I have to identify the 5v reg. :).? If I had to guess I would say it is on the board connected to the arduino and not on the arduino itself correct? |
Vic WA4THR
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