Aaron,
Attached is the PDF instructions for the AGC.
There are several options for the BCI here:
I have used the kits that are no longer sold.? Most of the kits for the uBitx series have been discontinued.? The sbitx is a better solution offered by HFSignals.
73
Evan
AC9TU
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Re: Nextion to fit v6 case?
To the best of my knowledge and experience, all 2.8" Nextion displays have the same mounting holes.? They need to be filed or Dremmeled out to fit the screw holes and posts on the V6.? The difference is the required tft file.
Mark, AJ6CU has a GitHub site with a collection of software and display files:
73
Evan
AC9TU
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Oh and I'm also in need of a broadcast filter. I never had any problems and I built a EFHW and now local radio stations are nearly overwhelming the uBITX V6, so again I would appreciate it if anyone knows someplace that sells a broadcast filter or even a set of instructions where I can build my own.? -- '72
Aaron?
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A couple of months back I ordered and received the uBITX AGC kit from INKITS.? I went to the INKITS website and tried to find the instructions for the kit and could not find them. I then tried to send a email but the email address listed on the INKITS website appears to be no good.? Does anyone happen to have the instructions for this kit that that can share with me?? -- '72
Aaron?
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Re: Nextion to fit v6 case?
Yes the 2.8 inch Nextion fits in the stock v6 case.? Please be aware that the holes in the case and the holes on the Nextion display do not align up properly. Two holes on one side of the Nextion display lines up with two holes on the case so you end up with just 2 holes supporting the Nextion display. It really isn't a big deal.? Having just the 2 holes got under my skin in appearance only, So I took a small round file and slightly enlarged the other holes in the Nextion PCB and now I'm able to use all four mounting screws.? I have no experience with the enhanced version though.? -- '72
Aaron?
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Is the 2.8 inch Nextion the one that fits the v6 case? Recomended part number for enhanced version?
73 John N4HNO
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Re: Where is the wsjtx_log.adi file?
#sBitx
Try the Import button. It will ask to save the adi file. Save to a location and you are done.
Bejoy, VU3BOJ
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Re: UBitx v6 - no transmit power
Nick,
I am glad that we could help.? Have fun with the uBitx!
73
Evan
AC9TU
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Re: UBitx v6 - no transmit power
Congrats Nick!
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On 11/05/2024 2:54 PM, nickredmayne via groups.io wrote: It lives!
Reflowed, rather than replaced, R60. Restored R1 (though your comments noted). Checked resistance - now in order.
At the same time, reflowed mic cable both ends, and removed redundant speaker from mic.
Turned on, pressed PTT, red led illuminated, and needle flickered up to 7 or 8 Watts with a loud 'Yes!'
However, attaching an antenna and tuning around 40m I couldn't hear any activity... strange... and then the aurora alerts started to ping in on my phone.
Gave a shout on 20m and made QSOs up to German/Danish border.
Thanks very much for your patience and that of Raj and others, guiding me through the diagnosis. I think the resolution wasn't entirely logical- my unreasoned methodology - but the result is very satisfying.
(Now to fit an AGC circuit...)
Best,
N
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Re: UBitx v6 - no transmit power
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Re: UBitx v6 - no transmit power
It lives!
Reflowed, rather than replaced, R60. Restored R1 (though your comments noted). Checked resistance - now in order.
At the same time, reflowed mic cable both ends, and removed redundant speaker from mic.
Turned on, pressed PTT, red led illuminated, and needle flickered up to 7 or 8 Watts with a loud 'Yes!'
However, attaching an antenna and tuning around 40m I couldn't hear any activity... strange... and then the aurora alerts started to ping in on my phone.
Gave a shout on 20m and made QSOs up to German/Danish border.?
Thanks very much for your patience and that of Raj and others, guiding me through the diagnosis. I think the resolution wasn't entirely logical- my unreasoned methodology - but the result is very satisfying.?
(Now to fit an AGC circuit...)
Best,
N
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You are right that the moment when the tuner tunes and the swr is high, that's when the final stage kills you. It's no coincidence that I always say to use a current-limiting power supply and, if possible, an antenna that does not require an antenna tuner.? This is how the repair remains in the event of an error.
--
Gyula HA3HZ
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Good info JJ, that's exactly what I needed. While the mosfets where in the board it looked like there was a short between pins, but it kinda drained like a capacitor. So I pulled one off the board and saw ~150ohm between drain and gate and 2Mohm
between source and gate.? Replaced both of them being careful to keep the tiny diode on the wire so I could maintain polarity.? Everything is back to the way it was!??
No idea what killed them, swr is never higher than 1.5 except for the brief moment when the tuner kicks in when switching bands.? Guess I better buy another set or two of spares!?
Now that I'm set to test if it is more stable, it's a massive CME weekend, all the bands are dead.? So I'll try again when that passes.
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Assuming you only have a multimeter, you can try this..
Shorted Pin Check
- Set your multimeter to the continuity or diode test mode.
- Check for shorts between each pair of pins (Gate-Drain, Gate-Source, Drain-Source).
- There should be no continuity between any of the pairs. A beep or low resistance reading indicates a short circuit, and likely a damaged MOSFET.
Resistance Check
- Set the multimeter to resistance mode.
- Connect the multimeter leads to the Drain and Source pins.
- Without applying any voltage to the Gate, the MOSFET should be "OFF", showing high resistance (ideally, it should appear as an open circuit).
?
-JJ
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That is not plastic, that is a mica sheet. It electrically insulates the transistor body (which is connected to the drain at 12v) from the heatsink while providing thermal conductivity to drain away heat from the transistors. It must be there otherwise the transistors will short the power supply to the ground, releasing magic smoke and sadness. - f
Aluminum nitride is a better choice for insulators than mica.? The AlN has better heat transfer, and it is almost the same as the aluminum heatsink.? Look for them in normal online places like eBay, AliExpress, or Mouser.? Look for sheets or predrilled forms for TO-220 transistors.? The way the finals are mounted in the sbitx allows for undrilled sheets.
73
Evan
AC9TU
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Well I'm really glad I asked. I would have tossed it right out! I'm assuming heat is what killed my finals, as swr never goes above 1.5 except for a brief moment when my tuner is doing it's thing.? So I'll pick up some AlN on my next trip to
digikey, thanks for the tip!?
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Aluminum nitride is a better choice for insulators than mica.? The AlN has better heat transfer, and it is almost the same as the aluminum heatsink.? Look for them in normal online places like eBay, AliExpress, or Mouser.? Look for sheets or predrilled
forms for TO-220 transistors.? The way the finals are mounted in the sbitx allows for undrilled sheets.
73
Evan
AC9TU
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Aluminum nitride is a better choice for insulators than mica.? The AlN has better heat transfer, and it is almost the same as the aluminum heatsink.? Look for them in normal online places like eBay, AliExpress, or Mouser.? Look for sheets or predrilled forms for TO-220 transistors.? The way the finals are mounted in the sbitx allows for undrilled sheets.
73
Evan
AC9TU
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Status update: I have the bare pcbs and encoders. Just waiting for the connectors to show up early next week so I can do a quick test to make sure I didn't mess up. I'm setting up an Etsy store, as this is an entry into hopefully more radio
things (working on low cost band pass filters). Stay tuned, if all goes well mid to late next week they should be ready.
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Yeah I would like the opportunity to order a board as well.??
--
'72
Aaron?
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Yeah I would like the opportunity to order a board as well.?? -- '72
Aaron?
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Depending on circuit design and pin layout, it is often necessary to insulate the flat back metallic side of transistors from ground. This used to be done with thin sheets of mica with heat sink compound. Now many applications will use manufactured insulators such as silicon, or such. The idea is to transfer heat, but not be electrically connected. I would say that if the insulators were found in place, install the new transistors with them in place. I would verify isolation with an ohm meter also. Otherwise,? you may get unwanted smoke escaping from other components.
Scotty WD4PYT?
On Fri, May 10, 2024, 7:36 PM Jeff Duce via <jefe_de_estado= [email protected]> wrote: Is there supposed to be a piece of plastic between the IRF510s and the heatsink? (The smaller oval shaped piece.)
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I believe so, mine has that as well -- '72
Aaron?
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Aaron K5ATG
Raj vu2zap
HA3HZ
Scotty R