LCD power and high pitched noise

omgitsaheadcrab
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LCD power and high pitched noise

Post by omgitsaheadcrab » Wed Jan 23, 2019 11:40 am

Hi,

I've finally got time to build my circuit sword and am testing components. All tests worked until I connected the 320 LCD.

This has no power as the backlight won't turn on and I can hear a high pitched noise (coming from the pi afaik). When I plug in the 640 LCD the backlight turns on and the noise is gone but it doesn't show any image - I'm assuming that'll be a missing config setting though.

Is my 320 LCD borked? Could it be insufficient power even though it seems to be enough to power the larger screen?

I wanted to complete the build with the lower res screen first and upgrade to the larger one in future..

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kite
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Re: LCD power and high pitched noise

Post by kite » Thu Jan 24, 2019 4:12 am

Hi, starting with the simple things: are you putting the 320x240 LCD FPC in the right way up? Perhaps a picture of how you have connected it?

The noise that is being made, is it the same as when there is NO LCD connected at all? (this is expected, and it's just the back light inductor squealing because no LCD is connected)

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Re: LCD power and high pitched noise

Post by omgitsaheadcrab » Thu Jan 24, 2019 9:26 am

Hey,

The buzzing is still present when no lcd is connected. I did notice however that the pgood light isn't on as you can see in the attached picture.

I tried with and without the battery and even used a new power adapter to make sure it had enough juice.

I should be receiving a new sd card tomorrow but it does seem like the image on this one is fine.
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Re: LCD power and high pitched noise

Post by kite » Thu Jan 24, 2019 9:34 am

It's curious that the 640 LCD lights up..

My thoughts are that the 320x240 LCD is faulty (backlight should come on no matter what) and that you possible have the 'bad SD connector' issue..

Could you test with the new SD that you receive, and if no change (no PGOOD) please send me an email and I'll sort out a return/repair/replacement for the LCD and main board, and that'll get you up and running :)

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Re: LCD power and high pitched noise

Post by omgitsaheadcrab » Fri Jan 25, 2019 4:16 pm

The 640 LCD also does not light the PGOOD LED, so there's that. Still waiting on the new SD card, it'll be Monday I guess.

PS. Someone on Github posted an issue a couple of days ago, same thing but his LCD backlight comes on.

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Re: LCD power and high pitched noise

Post by kite » Mon Jan 28, 2019 2:49 am

Yep that issue is the 'bad SD connector' issue that was originally called "known issue #12", keep me updated

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Re: LCD power and high pitched noise

Post by omgitsaheadcrab » Mon Jan 28, 2019 4:29 am

No luck with the new SD card, still no backlight or PGOOD LED, I'll send you an email.

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Re: LCD power and high pitched noise

Post by omgitsaheadcrab » Sun Feb 03, 2019 5:42 pm

I'm not sure I'm emailing the right email address :?

Can you pm me a postal address for me to send the CS and the screen to?

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Re: LCD power and high pitched noise

Post by omgitsaheadcrab » Tue Feb 19, 2019 5:07 pm

Hi Kite,

The replacement board arrived today. The PGOOD light turns on with this one, so that is sorted!

The LCD remains pitch black however, with no sign of the backlight turning on. Any ideas? I can only guess that the memory flash didn't work? I might try compile it myself rather than using your image.

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Re: LCD power and high pitched noise

Post by kite » Wed Feb 20, 2019 2:25 am

omgitsaheadcrab wrote:
Tue Feb 19, 2019 5:07 pm
Hi Kite,

The replacement board arrived today. The PGOOD light turns on with this one, so that is sorted!

The LCD remains pitch black however, with no sign of the backlight turning on. Any ideas? I can only guess that the memory flash didn't work? I might try compile it myself rather than using your image.
Try a different SD card, and use the image on github. Make sure you use the right one :) also maybe show pictures how you have it all connected? The PGOOD being on does sound like it's booting OK though..

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