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v4 pop-fix on a v3 board #ubitx

Nigel G4ZAL
 

I added the v4 pop-fix to my v3 board by placing components directly onto the v3 board.
Start by drilling a small hole (0.7mm in my case) to the right of R70 so as to be able to fix the 2N7000 transistor.  Pin 2 of the 2N7000 is soldered on the underside of the board (ground).
Scrape a little varnish from the tracks and tin ready to fix the 2N7000.
I added some Kapton tape to stop any shorting of components.




Add the remainder of the components and run a bit of enameled wire to the trace near the raduino headers to pickup the T/R line.






Ignore the cutouts on the front of the board, I had to hack away a little to clear the 3.5mm sockets on my case (I had to add a small length of enameled wire on the underside as I had hacked through a board trace).

So far, so good with no problems to report.

Nigel.

Nigel G4ZAL
 

Forgot to mention, I also swapped out R70 from 100 ohms to 1K.

Nigel.

Don Meyerhoff
 

Good stuff. Just put one together myself. A little separate breadboard which I used a small portion so as to have room for another mod or two. Installing the Nextion 3.2 tomorrow. Love the ability to mod and work with it. Great value for the money.

73

Don Meyerhoff
WA2SWX

On Tue, Jul 3, 2018, 8:19 AM Nigel G4ZAL <nigel@...> wrote:
Forgot to mention, I also swapped out R70 from 100 ohms to 1K.

Nigel.

Mark M
 

Nice clean mod, Nigel...a lot neater than the way I did it.

Does the CW sidetone still work? When I did it it killed the sidetone. I used M1 instead and that fixed that issue. I think there was some discussion about it in another thread. I left R70 alone.

Mark AA7TA

Michael Shreeve
 

Looks easy enough. But, I'm wondering just how good the audio is on the V4 board with the new 3 transistor audio amp. Is it worth having ? So Few new V4 boards out there. I know of one not far from me and I'm waiting for his critic (ND6T)  If so, there is a schematic available , with a board pattern, and perhaps he sells boards. This board has the pop fix, audio amp, and a page is available, its here  http://vu2kyz.blogspot.com/ . It also has an lm386 for use with Ians software so you have a working S meter. I remember the lm386 as a audio output amplifier of some kind, used years ago, I'll have to look it up. 

Nigel G4ZAL
 

@Mark, not sure on sidetone as I haven't checked and I understood swapping out the R70 resistor rectified the sidetone problem?

My shack/man cave is now partly cleaned out ready for a mains wiring and network cabling fit out so the uBitx is sidelined for now...

@Michael, I have no idea on the v4 board audio and this topic is regarding the v3 board and retro-fit of the 'pop-fix'.