Title: mcHF rev 0.7 - RED screen
Post by: S58J on 06. May 2018, 23:37:23
Hi
I just did the modification for limiting unwanted interaction between the UI and LOGIC boards (adding capacitors to P2a, P2b and P2c connectors - total 26 capacitors). During power on SOMETIMES I get the red screen (see the photo bellow).
I repeat, it happens sometimes during power on, and after pressing Power button for the second time mcHF powers up normally. Before the mod involving additional capacitors I have never seen this screen. I used 100nf capacitors (20 pcs) on all pins except for the encoders I Q lines. There I used 1nF capacitors (6 pcs).
Any idea?
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Title: Re:mcHF rev 0.7 - RED screen
Post by: DF8OE on 07. May 2018, 11:22:11
Yes: using 100nF *can* simulate pressing of function keys simultaneously and lead to entering startup special functions like loading defaults, touchscreen calibration, button test.
The best would be to remove all these capacitors - but weird PCB layout of 0.7 needs that modification.
First approach would be to reduce capacitors on F-keys from 100nF to 10nF.
vy 73
Andreas |
Title: Re:mcHF rev 0.7 - RED screen
Post by: S58J on 07. May 2018, 20:40:28
Hi Andreas
Thanks for the reply and the advice. Yes, I will change the 100nF caps to 10nF.
For the rest, I attached a photo how my mod looks like (green coloured caps are 1nF).
Best 73
Janez, W4/S58J |
Title: Re:mcHF rev 0.7 - RED screen
Post by: DF8OE on 08. May 2018, 06:43:59
Very bad that this is neccessary. You definitely slow down your reaction time to buttons / encoders. It is mighty design issue...
vy 73
Andreas |
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