Re: Finished to build but LCD noise.
开云体育Please Jack,
send us the schematic of the modified PSU.
?
73 Carlos
CX8ABF
? Sent: Saturday, July 29, 2017 11:44 AM
Subject: Re: [BITX20] Finished to build but LCD
noise. ?
I had the same noise problem with my
TFT display. Because of all the add-on boards that Dennis is working on, I
needed additional takeoff points for +/-12V (mainly for BITX40, PA, and Dennis'
boards) and +/- 8V (the TFT and my DDS). My original design for the PS
introduced a ground loop into the circuit and updating the display created an
ugly "whoosing" sound. (Hey! What do I know? I'm a software guy.) Under the
guidance of Al Peter, AC8GY, I redid the PS (see picture) to eliminate the
ground loop. The power comes into the pins on the left, and the yellow pins at
the top of the board are +12V feeds (black is GND), the middle yellow pins are
+8V for my PCB (less stress on the Mega), and the bottom single set is for the
PA. The lone yellow pin near the top right feeds into pin A14 on the Mega to
monitor the supply voltage (which might be a battery) on the display. Now there
is no interference when tuning.
Jack, W8TEE
From: Mvs Sarma <mvssarma@...> To: [email protected] Sent: Saturday, July 29, 2017 5:22 AM Subject: Re: [BITX20] Finished to build but LCD noise. ?
the power supply going to
raduino has to be filtered at -close to raduino? by say 100uF and?
0.1? disc cap or MLC cap.
? ?
On
Sat, Jul 29, 2017 at 1:52 PM, <qrper72@...> wrote:
-- Regards Sarma ?
|
CX8ABF Carlos Molina