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Hi,

I'm scratch building my SMD uBITX V6 on two 100x100mm PCB ?Some info can help me a lot

to verify every part of the circuit. In every one of the same 4 amplifiers,

what is the gain I can expect? Sending 10mVpp rf on the base of the first transistor,

what signal will I have on the emitter of the third one?

I've used what seems the very same TFT touch screen display on Fahran web site, but it refuse to work

at 5Vcc, other similar circuits use resistors or CD4050 as level translators.

If I use 3.3Vcc display works, but not touch screen, probably damaged by 5V: possible?

CEC file.hex for 16x2 display seems to work for 12MHz, not 11.059: help!!
I'm using an ATMEGA328, not an Arduino: this save space.....
Hope some builder and expert can exchange infos

Thank you

Paolo

Here are the two 100x100mm PCBs

there is a bridge on the bottom side of tft to short circuit the small 7803 if we do not want to use 5Vcc but 3.3Vcc, but?
internal IC seems to like 3.3V , at least the ones on my TFT. It seems the very same as the one on

Paolo

Hi Paolo,
Your TFT display issue is not exactly clear.? The I/O levels of the display need to match the I/O levels from your ATMEGA328.? You can run the ATMEGA328 at 5V or also at 3.3V.
I assume you are running a 5V ATMEGA with no level shifters like what is done on the HF Sigs uBITX v6.
In this case, you need to run the display's board VCC at 5V and bypass the 3.3V regulator by placing a short/jumper at J1.
With overvoltage on the IC, it functions at 5V I/O levels.? (That comes at the cost of higher power consumption, more heat and shortened lifetime due to higher voltage and temperature.)
(the other case where you bypass the regulator is when you wire VCC to 3.3V for 3.3V operation, i.e. your system doesn't have a 5V source)

VCC	J1	I/O
3.3	short	3.3
5	short	5
5	open	3.3

The display board you have appears to be the correct one.
If you tried the display board configured in a 3.3V configuration with 5 V I/O levels on the ATMEGA, you _may_ have broken the touch sense IC.? But a 'not working' touch screen could also be a calibration issue.? Run the touch screen calibration.

I'm running 3.3V I/O levels on my v6.
/g/BITX20/message/101562

links from my? voltage conversion notes.

Regards,
Gary

Thank you Gary, now everything works @5Vcc ( but no more touch screen, of course!)

I can probably save energy at 3.3V, but I use the 5351 board from Cina,

working @5V. There is always something to learn, for example?

not all BAT54 are the same.....I need BAT54SL, not a common BAT 54,

or 54A or 54C, and of course I buyed the wrong ones... :-)))))

C81 on emitter of Q90 must be 100nF, and not 470pF as indicated on V6.

Still a lot of fun, also at 68 y.o.

paolo

?

My homebuilt uBITX works on 7MHz without problems, I can listen?

with a 5 meters wire on the floor . I can also generate? SSB, up to 36Vpp

( 9Wpp), still to verify quality. But when I go on 14MHz it seems to loose sensibility,?

audio volume goes very low: what can be the problem? Capacitors on input low pass filter

( and all capacitors used) are verified with LCR meter before soldering, all components are absolutely new never used before.

Any help appreciated

Paolo

After using an? ATMEGA328 with 16x2 display withot problems, now I'm testing Arduino with? an expensive Nextion 2.8". No problem to load Arduino with XLoader, and no problem to load file.tft inside SD card,?but I too have the error message : file version is too low. It does not seem a problem of SD card, because from same card I can load other .tft files? without problems. It really seems .tft is? created with an old version of editor , non accepted by a? new Nextion display.?With file.HMI Nextion editor gives me an error message : Error:Page:pqrcode The remaining memory is not enough to run ...... I'm unable to find a solution: help needed!!!!!!

Paolo

?

Hello Paul,

I solved the size issue by removing the QR code screen. ?Since I could backup and restore the settings using the Memory Manager program, it seemed redundant. ?That allowed the program to fit into the display memory.?

I hope this helps.?

73
Evan
AC9TU

Evan , with your help the problem is solved.

I strongly suggest yuor file to scratch builders with same problem

Thank you !

Paolo