Re: Finished to build but LCD noise.
开云体育Thanks Jack
73 Carlos
? Sent: Saturday, July 29, 2017 12:05 PM
Subject: Re: [BITX20] Finished to build but LCD
noise. ?
I'll try to get that done
this weekend and then post it.
Jack, W8TEE
From: CX8ABF Carlos Molina <cx8abf@...> To: [email protected] Sent: Saturday, July 29, 2017 10:55 AM Subject: Re: [BITX20] Finished to build but LCD noise. ?
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