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I'm stymied....
After building my kit I very quickly put it on Ft8 to check it out. It received apparently ok. With pskrporter I saw my transmissions registered all over north America. I then plugged in a head set and heard Nothing. Tried a second headset still nothing. Switched the CW keyer to practice mode, no audio. If I use a cw key and put a power meter on when I key the paddle I get about 4 watts out.
There is a click when I power up and power down, but when on receive or during CW practice mode there is just no audio what so ever.? I've looked over the board with a loupe at least 20 times. My soldering isn't professional but I don't see any missing smd parts, broken smd parts, or really bad solder joints. I've attacked an image incase someone knows an obvious location to look.? Any help in where I could look next for trouble shooting would be greatly appreciated.? 73, Don KC9ZMY |
Well I have tried all the suggestions, quadruple checked the solder joints. There is NO sound other then the initial click at power up. It will work fine on Ft8. With FLdigi I can decode CW. The Device successfully Will transmit CW and decode CW both with the Key and on the air. Just nothing out of the head phone jack. I purchased another kit and am going to build it and then compare and contrast the two. If anyone has any other suggestions I'd love to try them.?
? Don..? |
?Don
If you would like to try signal tracing Here is a? very nice PC soundcard oscilloscope for win XP and above As you know surface mount components are packed tight Be careful probing I use a hat pin, small sharp point so not to skip off component es short to another,? plastic knob so personal contact does not introduce noise or 60 Hz junk https://www.zeitnitz.eu/scope_en It is also dual channel with a spectrum analyzer and sweep generator? And Free 72 73 John N3AAZ |
possibly either a duff jack socket or duff phones..
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On 2 Sep 2023 at 7:34, Donald Gover wrote:
Well I have tried all the suggestions, quadruple checked the solder joints. There is NO sound other then the initial click at power up. It will work fine on Ft8. With FLdigi I can decode CW. The Device successfully Will transmit CW and decode CW both with the Key and on the air. Just nothing out of the head phone jack. I purchased another kit and am going to build it and then compare and contrast the two. If anyone has any other suggestions I'd love to try them. Don.. |
Don, The audio amplifier for the headphone jack is IC404. You should check it for proper bias voltages. I didn't see if you wired the radio for 9v or 12v, but you should find a little less than half that voltage on pins 1,2,3,5,6&7 of IC404. That voltage is supplied by a resistive voltage divider made up of R423 and R424. If those voltages are good, then you will need to inject an audio signal into the inputs (it's a stereo amp connection) pins 2 and 6 and look for them to come out on the left and right channels. If that test is good, then you may have an issue with the D/A converter IC401or the RC filter circuit between it and IC 404. Refer to the schematic and parts layout diagram for the above parts. Good luck ... Ron On Sun, Sep 3, 2023 at 5:33?AM K9NUD-Steve <k9nud@...> wrote: I overheated my headphone jack on the initial assembly. I swapped it with the PTT jack to get up and running. It's not uncommon, these little jacks can't handle much heat. |
Don,
the condition of your QMX reflects exactly what I'm getting.? I've built several qrp-labs kids but never had a sound issue. I just wondering if we are unlucky and have a duff board. on a side issue my BNC connector was so stiff that today when I unplugged the coax cable it pulled the innards of the board bnc. connector with it breaking of the pin making it basically non repairable. I'm gonna replace it with an ama connector as I believe Hans has provided for both types of connectors.? Paul DJ0CU G4ADF? |
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Ok, I have searched and cannot find out what an ama connector is. Can you please explain?
I have wired my whole shack with RG-6 Quad Shield using type F connectors. Yes, do understand it is 75 ohm, but have solved that problem. Have 75 ohm SWR bridges to start with. Was restricted to VHF/UHF for a few years and came upon a good supply of Quad Shield.
Just like uhf cable and sattalite, the Quad Shield beat the regular plain coax. I've got it now, so I have to use connector adaptors on all my current rigs.
73, Billy
From: [email protected] <[email protected]> on behalf of Paul Harrison via groups.io <dj0cu@...>
Sent: Sunday, September 3, 2023 10:32 To: [email protected] <[email protected]> Subject: Re: [QRPLabs] I'm stymied.... ?
Don,
the condition of your QMX reflects exactly what I'm getting.? I've built several qrp-labs kids but never had a sound issue. I just wondering if we are unlucky and have a duff board. on a side issue my BNC connector was so stiff that today when I unplugged the coax cable it pulled the innards of the board bnc. connector with it breaking of the pin making it basically non repairable. I'm gonna replace it with an ama connector as I believe Hans has provided for both types of connectors.? Paul DJ0CU G4ADF? -- N5SE Billy Wayne Moore 7066 Shady Knoll Ln Willis, TX 77318-6324 Phone: 936-537-2975??? |
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Rick (NF6G),
SMA, that I understand. All of my low powered interconnects use SMA. Quite successfully I might add.
Thanks very much, Billy (N5SE)
From: [email protected] <[email protected]> on behalf of Rick NF6G via groups.io <rdante@...>
Sent: Sunday, September 3, 2023 11:19 To: [email protected] <[email protected]> Subject: Re: [QRPLabs] I'm stymied.... ?
Billy, I believe what Paul was referring to is an SMA connector.
-- N5SE Billy Wayne Moore 7066 Shady Knoll Ln Willis, TX 77318-6324 Phone: 936-537-2975??? |
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