Re: installed QMX Rev 2 diode mod, now it is deaf
And now it works, rf filter sweeps keep changing.
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Re: installed QMX Rev 2 diode mod, now it is deaf
Now my swr sweeps show flat lines at 10. No power out when tuning in diagnostics. Swr protection trips. Dummy load attached.
Yikes. I really broke something.
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Re: installed QMX Rev 2 diode mod, now it is deaf
I did a recheck of L401. Everything seems good. QMX was A+ 100% beofrw i attempted the diode mod.
The issues on 20m and 30m are new, after diode mod attempt.
73 K9PZ
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Yes, Stefan, that is a short! ... JZ
On Tue, Jan 16, 2024 at 5:11?PM Stefan U. Hegner < db4st@...> wrote: Hi John,
Am 16.01.24 um 22:31 schrieb John Z:
> Stefan, that transistor appears to have suffered a gate-drain short.
> You can probably confirm that with an ohmmeter.
I'm measuring 120 Ohms ... that's close enogh to a short for me.
Thanks for the confim. Part is orderd. Hopefully I can report a "solved"
next weekend.
Mni Tnx & Vy73
Stefan.
--
Stefan U. Hegner? ? <db4st@...>
? ? ? ? ? ? ? ?* * *
DB4ST --- German Ham Radio Station
D-32584 L?hne ----- Locator JO42IE
? ? ? ? ? ? ? ?* * *
GPG-Key | C3CC 23A4 FBA8 622B 48AE
F-Print | 4F19 D0EE E39E ABDC 2BCE
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Re: Both QDX units lost ability to transmit?
The slider was all the way up .......... Long pause........
Then checked the volume in the sound manager..........
Longer pause.........
And the winner is .............. The volume controls on the computer sound manager!!!!
Yes Ladies and Gentlemen, I did not look at the obvious problem and there it was all the time!!
Thanks..... And when we meet at the next event you can shake my hand and tell me you knew it all the time.... You were just trying to help me mature a little in the craft??????
Have a great evening and thanks again till your better paid
73
James?
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Re: installed QMX Rev 2 diode mod, now it is deaf
Next, recheck the solder joints at L401. There may be some unremoved enamel remaining on the wires...JZ
On Tue, Jan 16, 2024 at 5:00?PM k9pz < kd9okx@...> wrote: Thank you again.
It was very difficult to install, i think there was insufficient clearance with the case causing the damage.
I was able to goober enough solder on to L503 to regain continuity. 80,60,and 40m are all back in spec.
Tx is stable.
Audio and rf sweeps on 20 and 30m are still terrible.
73 K9PZ
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Hi John, Am 16.01.24 um 22:31 schrieb John Z: Stefan, that transistor appears to have suffered a gate-drain short. You can probably confirm that with an ohmmeter. I'm measuring 120 Ohms ... that's close enogh to a short for me. Thanks for the confim. Part is orderd. Hopefully I can report a "solved" next weekend. Mni Tnx & Vy73 Stefan. -- Stefan U. Hegner <db4st@...> * * * DB4ST --- German Ham Radio Station D-32584 L?hne ----- Locator JO42IE * * * GPG-Key | C3CC 23A4 FBA8 622B 48AE F-Print | 4F19 D0EE E39E ABDC 2BCE
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Re: installed QMX Rev 2 diode mod, now it is deaf
Thank you again.
It was very difficult to install, i think there was insufficient clearance with the case causing the damage.
I was able to goober enough solder on to L503 to regain continuity. 80,60,and 40m are all back in spec.
Tx is stable.
Audio and rf sweeps on 20 and 30m are still terrible.
73 K9PZ
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Stefan, that transistor appears to have suffered a gate-drain short. You can probably confirm that with an ohmmeter.
JZ KJ4A
On Tue, Jan 16, 2024 at 4:20?PM Stefan U. Hegner < db4st@...> wrote: Hi Folks,
Am 15.01.24 um 22:00 schrieb Stefan U. Hegner:
>> [...] test that Q508 is turned on while receiving.? The source and
>> drain should be close to zero volts.
>
> Not so sure on this one: Drain 0.64V, Source 0.07V, Gate 0.69V - no
> matter what band I select. - Is this maybe the suspect? Strange, as
> there was no re-soldering in that vicinity.
>
> [...]
>
> But my interpretation would be a fried Q508 ... so change one BSS123
> MOSFET.
>
> Please confirm this diagnosis
>
As 0.64V at the drain is not close to 0V, I suspect the Q508 ... but I'd
appreciate some confirmation on my interpretation, if that is possible,
before ordering parts and heating up the soldering iron ... Thank you so
much.
Vy 73 & mni tnx
Stefan.
--
Stefan U. Hegner? ? <db4st@...>
? ? ? ? ? ? ? ?* * *
DB4ST --- German Ham Radio Station
D-32584 L?hne ----- Locator JO42IE
? ? ? ? ? ? ? ?* * *
GPG-Key | C3CC 23A4 FBA8 622B 48AE
F-Print | 4F19 D0EE E39E ABDC 2BCE
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Re: QSX: I'd like to purchase a fully assembled & tested QSX
My two QMXs are on the waiting list...YIPPEE !!!
72,
Bill, N4QA/4
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Re: installed QMX Rev 2 diode mod, now it is deaf
Brandon, I recommend you install an SMD diode SOD323 style. 1N4148 or 1N4448. The leaded glass diode is difficult to install w/o breaking something. The leads are too strong. Good luck...JZ KJ4A
On Tue, Jan 16, 2024 at 4:19?PM k9pz < kd9okx@...> wrote: No continuity. Thanks JZ. I'm new to this surface mount stuff. I can see it now. Will try to find a replacement. Hopefully thats all i broke.
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Hi Folks, Am 15.01.24 um 22:00 schrieb Stefan U. Hegner: [...] test that Q508 is turned on while receiving.? The source and drain should be close to zero volts. Not so sure on this one: Drain 0.64V, Source 0.07V, Gate 0.69V - no matter what band I select. - Is this maybe the suspect? Strange, as there was no re-soldering in that vicinity.
[...]
But my interpretation would be a fried Q508 ... so change one BSS123 MOSFET.
Please confirm this diagnosis
As 0.64V at the drain is not close to 0V, I suspect the Q508 ... but I'd appreciate some confirmation on my interpretation, if that is possible, before ordering parts and heating up the soldering iron ... Thank you so much. Vy 73 & mni tnx Stefan. -- Stefan U. Hegner <db4st@...> * * * DB4ST --- German Ham Radio Station D-32584 L?hne ----- Locator JO42IE * * * GPG-Key | C3CC 23A4 FBA8 622B 48AE F-Print | 4F19 D0EE E39E ABDC 2BCE
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Re: installed QMX Rev 2 diode mod, now it is deaf
No continuity. Thanks JZ. I'm new to this surface mount stuff. I can see it now. Will try to find a replacement. Hopefully thats all i broke.
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Re: installed QMX Rev 2 diode mod, now it is deaf
Check L503 for continuity. It may have been damaged.
JZ KJ4A
On Tue, Jan 16, 2024 at 3:46?PM k9pz < kd9okx@...> wrote: I installed the diode and two days later started experiencing the audio issues others have been reporting.
The audio sweeps on 20m and 30m are erratic and 70db down. The sweeps on 80, 60, and 40m retain the correct shape but are about 50db down.
Power out is unstable on 20m via diagnostics, fluctuates between 3.5 and 4.5w.
I uninstalled the diode and nothing changed.
If i touch the windings on L401 audio improves on 40m.
I really screwed it up good this time!
Any tips would be greatly appreciated, i will see what else i can dig up.
Thanks
73 Brandon K9PZ
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installed QMX Rev 2 diode mod, now it is deaf
I installed the diode and two days later started experiencing the audio issues others have been reporting.
The audio sweeps on 20m and 30m are erratic and 70db down. The sweeps on 80, 60, and 40m retain the correct shape but are about 50db down.
Power out is unstable on 20m via diagnostics, fluctuates between 3.5 and 4.5w.
I uninstalled the diode and nothing changed.
If i touch the windings on L401 audio improves on 40m.
I really screwed it up good this time!
Any tips would be greatly appreciated, i will see what else i can dig up.
Thanks
73 Brandon K9PZ
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Appears that my Email address didn't make it on my for Sale stuff. Ed Pflueger AB4IQ ab4iq@...?
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Has anyone got a photo of the bottom of the PCB with the pins in question at which to make the CAT connections? I am not able to locate any and I'm hesitant to risk blowing up my QXC(s) before knowing exactly where to tap these - and seeing them indicated on a photo or diagram, and not the wiring diagrams that are out there, I mean actual wires soldered on a successful mod.
Thanks, Rob, KC4NYK
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I have the following QRP Lab kits for Sale.? Winter is here and need to sale what I have built.? If interested you can reach me off line at ab4iq@.... 1.? QMX Low Band (12 Volt) with case? ? ? ? ? ? ? ? ? ? ? ? ? $135 Shipped 2.? 40 Meter QCX Mini with AGC and TXCO and case? $125 Shipped 3.? 40 Meter Mini with AGC and Case? ? ? ? ? ? ? ? ? ? ? ? ? ? ?$119 Shipped 4.? 40 Meter QCX+ with AGC, TXCO and case? ? ? ? ? ? ? ?$125 Shipped 5.? 30 Meter Original QCX with TXCO and Case.? ? ? ? ? ? $80? Shipped 6.? NorCal 40B.? does not have the bells and whistles like the QRP Labs but works from 7.000 Mhz. to 7050 Mhz. CW straight paddle $125 Shipped I Accept PayPal Friends and Family, Personal Check, Money Order? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ??
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Re: Both QDX units lost ability to transmit?
On 16/01/2024 18:57, KB9NBL wrote: but no transmit power. James, Possible that you accidently caused the WSJT-X power slider to drop? 73 Alan G4ZFQ
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Both QDX units lost ability to transmit?
Greeting,
Have been using this set up for 6 months on this computer. no problem except the dreaded Hamlib issue that I resolved.
I have 2 QDX units Low 5 band and High Mono version. Using a tuner at all times for 1.1 SWR.
Using Linux Mint, Virginia
Using WSJT-X 2.6.1
Issue:
?Sudden loss of transmit power during QSO with high band mono on the 13th of January. Receiving, but not transmitting.
Restarted WSJT-X thinking.... Hiccup.... Still receive, but no transmit power.
Tried QDX low band and same issue.
When I went into putty to check .....They both transmit fine as expected into my QRP O' Meter.
Anyone else run into this??
Any help is greatly appreciated
James?
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KB9NBL
Bill, N4QA/QRP
Rob - KC4NYK