If one of the MOSFETS? ?**shorts**? the entire system fails to operate because it shorts out the power supply, may blow fuses, and you cannot establish the needed voltage on the system due to the short circuit from?+v to ground through the shorted mosfet.
The problem you are having is very different and Im quite?curious what you find as the cause!
I had a similar faiure once (no short, just loss of power) with still tiny bit of output (approx 20db down).? ?Problm was plastic movement of SOLDER which ended up with poor connection for one of the final MOSFETs? ? Re soldered, worked fine!
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If you are in there, and can get access to Aluminum nitride insulators, I would consider replacing the mica with the alum nitride which have much better thermal conductivity.? ?Might keep the junction considerable cooler by making the heat sink considerably HOOTTER.??
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Of course, could have fried the mosfet.? ? The latter has only happened to me once and it resulted in a shorted mosfet -- comletely shorted
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Good luck!
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While in there, it is up to you whether to add back in the TVS diodes.? ?They are incredibly tiny.....? Ashhar thinks they are unnecessary with the V3 ciruitry.
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I do not think that you can put in the IRF520 beause the V3 circuitry is not designed to drive the much higher input capacitance of the IRF520
Looks like the images didn't render properly in the first message, so here's a repost:
We're all set to start shipping out the zBitx units in batches starting next week and customers?should?receive your tracking number once their unit is ready to ship out.
Meanwhile, we wanted to introduce the zBitx and offer you an insight into the making of the zBitx so that you can appreciate the work and effort that goes into manufacturing these radios.
?
Here is a short video of the zBitx in action:?
?
?
We'd like to share some updates from the zBitx assembly line at our facility in Hyderabad, India.
?
Once the boards arrived, the team started with the assembly. They put together all through hole parts such as the coils, connectors, regulators, headers, etc.
These boards were then handed to the next team who soldered the IRF MOSFETS and mounted them to the back panel, that serves as the heatsink.?
?
While this was in progress, another team started work on the display board and soldered on the display, Raspberry Pico, encoder, connectors, and speaker.
?
?
Once the display boards were completed and integrated with the RF board, they went through a round of mechanical and electrical inspection.? Once this was done, the boards were ready for the enclosure.
?
?
?
?
?
After testing, the radios were packed along with the test report and kept ready for dispatch.
?
The dimensions of the radio are 139x84x37mm and weighs about 385 grams without the 18650 batteries and about 485 grams with batteries.
?
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?
?
?
Since there was a lot of confusion about the 18650 batteries for the zBitx, here is a photo of the batteries we used during testing. They do not come with tabs and are flat topped. Please note, batteries aren't included in the package.
Podpora vysokofrekven?ního signálu p?es <support=[email protected]> schrieb am Fr. 28. ?nor 2025 um 10:23:
V?ichni jsme p?ipraveni za?ít dodávat jednotky zBitx v dávkách od p?í?tího t?dne a zákazníci by měli obdr?et va?e sledovací ?íslo, jakmile bude jejich jednotka p?ipravena k odeslání.
Mezitím jsme vám chtěli p?edstavit zBitx a nabídnout vám pohled na v?robu zBitx, abyste mohli ocenit práci a úsilí, které je do v?roby těchto rádií vlo?eno.
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Zde je krátké video zBitxu v akci:
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https://youtu.be/3NSLHjw3Egg Rádi bychom se s vámi podělili o některé novinky z montá?ní linky zBitx v na?em závodě v indickém Hyderabadu.
Jakmile desky dorazily, t?m se pustil do montá?e. Spojují v?echny díly s pr?chozími otvory, jako jsou cívky, konektory, regulátory, headery atd.
Tyto desky byly poté p?edány dal?ímu t?mu, kter? p?ipájel IRF MOSFETy a namontoval je na zadní panel, kter? slou?í jako chladi?.
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Zatímco to probíhalo, jin? t?m za?al pracovat na zobrazovací desce a p?ipájel displej, Raspberry Pico, kodér, konektory a reproduktor.
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Jakmile byly zobrazovací desky dokon?eny a integrovány s RF deskou, pro?ly kolem mechanické a elektrické kontroly. Jakmile to bylo hotovo, desky byly p?ipraveny k ohradě.
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?
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Po testování byly vysíla?ky zabaleny spolu s protokolem o zkou?ce a p?ipraveny k odeslání.
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Rozměry rádia jsou 139x84x37mm a vá?í cca 385 gram? bez baterií 18650 a cca 485 gram? s bateriemi.
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Vzhledem k tomu, ?e ohledně baterií 18650 pro zBitx bylo mnoho nejasností, zde je fotografie baterií, které jsme pou?ili během testování. Nejsou dodávány s poutky a mají ploch? vr?ek. Vezměte prosím na vědomí, ?e baterie nejsou sou?ástí balení.
Help. ?I received the following email. It appears suspicious to me. It’s addressed to the group and not to me individually. I won’t push the “buttons” until I know for sure it’s not a Trojan horse or virus. Let me what you think. Thanks.?
On Feb 28, 2025, at 2:07?AM, 马玉麟 via groups.io <patrickylma@...> wrote:
?
? ? Important Update for Your Web-mail Account ? ??
?Dear Valued User,
We are pleased to notify you that your most recent?Web-mail E-Statement?is now available. This statement contains comprehensive details regarding your account activity, settings, and preferences. We kindly
urge you to review this information periodically to ensure the continued security and accuracy of your account.
We strongly recommend that you take a moment to carefully examine your update. This will enable you to stay informed of any recent changes and confirm that your account is configured according to your preferences.
?
Notice:As required, please click the button link below to download your invoice. If you are using a phone, please switch to a PC or laptop to view the invoice, as it is optimized for viewing on these devices.
Thank you for being a valued ?Web-mail user. We sincerely appreciate your prompt attention to this matter.
On Jan 8, 2025, at 06:41, David T-- VE3TOS via groups.io <digiital@...> wrote:
something like this would kill a few birds with one stone.
Yeah. So I bought the 9V version of that: I hope it’s really ok to give the radio 9V. Maybe that’s the upper end of the range it can support? And then maybe it would be ok to use LiFePO4 cells with that step-up circuit. It arrived, and I can confirm that the contacts are open, so they would work fine with flat-tops; and they’d better be 65mm long: 70 would be too long to fit (unless perhaps mashing the contacts down really flat).
Looks like I’ll have to design a 3D-printed case for it to mount on the radio. That’s fine.
I didn’t buy batteries yet, because it’s still ambiguous whether the radio’s included battery holder is better for button-top or flat-top cells, isn’t it? But the picture on the update that was just sent (the only picture I can see in that update!) is showing flat-top ones. "Aspire 2900mAh" seem to be intended for vaping, to such a degree that all the web sites are asking for confirmation that I’m 18 and then not showing tech specs very well.
From what I read so far, if you want LiPo, Panasonic NCR18650BD seem to be one of the best values: 3180 mAh, new safer chemistry first released in 2020, tested for surviving a lot of charge cycles, and Panasonic generally makes some of the best quality batteries (speaking of which: I bet the radio could alternatively run off 6 Eneloops in series, but that would be bulky). Anybody have any better recommendations?
Yes, the problem is the same on all bands. I think that the problem resulted from overheating (the heatsink was quite hot after long operation in FT8 on low bands). I think that after replacing the IRF510 (I have one pair delivered together with sBitx, and I have ordered a batch of them manufactured by Vishay), I'll attach the 12V fan to the heatsink.
Are you facing the same problem on other bands as well? Can you check the power out on 80,40, and 10 M? If the problem is persistent on all bands, you might have to have a look at the driver and the PA section.
IRF510's are quite rugged and you can use two unmatched IRFs from the same batch if matching them isn't an option.
We're all set to start shipping out the zBitx units in batches starting next week and customers?should?receive your tracking number once their unit is ready to ship out.
Meanwhile, we wanted to introduce the zBitx and offer you an insight into the making of the zBitx so that you can appreciate the work and effort that goes into manufacturing these radios.
?
Here is a short video of the zBitx in action:?
?
?
We'd like to share some updates from the zBitx assembly line at our facility in Hyderabad, India.
Once the boards arrived, the team started with the assembly. They put together all through hole parts such as the coils, connectors, regulators, headers, etc.
These boards were then handed to the next team who soldered the IRF MOSFETS and mounted them to the back panel, that serves as the heatsink.?
?
While this was in progress, another team started work on the display board and soldered on the display, Raspberry Pico, encoder, connectors, and speaker.
?
?
Once the display boards were completed and integrated with the RF board, they went through a round of mechanical and electrical inspection.? Once this was done, the boards were ready for the enclosure.
?
?
?
?
?
?
After testing, the radios were packed along with the test report and kept ready for dispatch.
?
The dimensions of the radio are 139x84x37mm and weighs about 385 grams without the 18650 batteries and about 485 grams with batteries.
?
?
?
?
?
Since there was a lot of confusion about the 18650 batteries for the zBitx, here is a photo of the batteries we used during testing. They do not come with tabs and are flat topped. Please note, batteries aren't included in the package.
I should have clarified, I am feeling frustrated that after everything was ready two months ago, we have been unable to ship it at all. Hopefully now that the production line is fully working, we shall be able to ship all the orders and take new orders to ship ex-stock too.
you are not Big nor small! You are great!? This was a massive challenge! What you have proposed to do, the close to 400 orders, the overcoming Of setbacks, and being able to build, configure and troubleshoot all units, from a never seen, never heard before transceiver. 400 orders!!??
After a month of perfect operation in FT8 mode, my sBitx v3 has stopped producing the output RF signal. I hoped it might be a software issue, like described here: .
Unfortunately, no correction in the software configuration restores the correct operation.
The status of my radio is as follows:
Reception works perfectly. The malfunction didn’t affect the receiver.
When I start transmitting in CW mode, the current consumption increases from 0.35A to 1.05A at DRIVE=100 or 0.84A at DRIVE=50. The peak-to-peak voltage at 14.068 MHz is ca. 11V for DRIVE=100 and 272 mV for DRIVE=50 (measured with 50 Ohm 40dB attenuator as a dummy load, and multiplied by 100)
The sBitx meter displays 0W and SWR=1.0
When working, the radio was used with the antenna matched via ATU-10-0A tuner with SWR up to 2.
The symptoms suggest that I have fried the transistors in the final stage due to too intensive usage in an FT8 mode.? Am I right?
Should I pair the replacement IRF510N transistors according to their threshold voltage when replacing them?
Is it possible to use IRF520 (with higher maximum ID) instead of IRF510?
I should have clarified, I am feeling frustrated that after everything was ready two months ago, we have been unable to ship it at all.
Hopefully now that the production line is fully working, we shall be able to ship all the orders and take new orders to ship ex-stock too.
? ? Important Update for Your Web-mail Account ? ??
?Dear Valued User,
We are pleased to notify you that your most recent?Web-mail E-Statement?is now available. This statement contains comprehensive details regarding your account activity, settings, and preferences. We kindly urge you to review this information periodically to ensure the continued security and accuracy of your account.
We strongly recommend that you take a moment to carefully examine your update. This will enable you to stay informed of any recent changes and confirm that your account is configured according to your preferences.
?
Notice:As required, please click the button link below to download your invoice. If you are using a phone, please switch to a PC or laptop to view the invoice, as it is optimized for viewing on these devices.
Thank you for being a valued ?Web-mail user. We sincerely appreciate your prompt attention to this matter.
WK4DS
Lev
DL4ZAQ_Peter
tzsantos CR7BOG