Display not working with micro USB / high pitch noise when charging

[Metalman1661]

Here are my hardware details:

-Kites Super AIO V0.5E1 20161221
-Kites Super AIO back board V0.2D1 161219
-Kites pre-made retropie image
-pi zero
-everything that came with my kit

Everything was working fine and I had the unit sitting on the retropie SNES screen and it randomly shut off. I had a keyboard plugged into the USB slot when this happened and was running on battery power. I heard a slight 'tick'when this happened.

I initially thought the battery died but when I plugged it into the micro USB and turned it on the unit was producing a high pitch tone, almost like a whine. Taking the unit apart it wounds like the sounds can be possibly coming from the pi zero.

Here are the symptoms:

1. With battery plugged in / micro USB plugged in - high pitch tone is present
2. With only battery plugged in - very faint sound can be heard from pi zero. Not noticeable unless you put your ear up to it.
3. Only micro USB plugged in - screen goes from dark to very bright, then back to dark. No picture but I can hear my splash screen so the unit is booting up. faint buzzing sound can be heard from pi zero.

Not sure what else can be of help. Powered pictures are of unit plugged in with micro USB only.

[kite]

Soldering looks good, does anything get hot? For example on the Pi itself or to the left of the LCD connector (D3/L2/U5)?

Does the backlight come on at all? As in when it's on and booted, what is the screen showing? More importantly is the backlight on at all or not?

Can you rework the 3.3v and vcc solder points on the Pi itself. So the pins in the far right corner (the square ones and the ones below it)?

Also can you add a little more solder/rework these PINK pins? https://github.com/geebles/Super-AIO/wi ... lay-at-all

There is a reset button on the board, when booted and you hold this button down, does the screen come to life?

When I say re-work, I mean add some solder to reflow it. Don't use a solder sucker or try and remove the board!

Lastly I assume you have tried another SD? Long short but a fresh image on a new SD is always a good start, but I can see from your pics the pi has booted (USB LED, and PI ON LED)

[Metalman1661]

Soldering looks good, does anything get hot? For example on the Pi itself or to the left of the LCD connector (D3/L2/U5)?

Will check when I get home later.

Does the backlight come on at all? As in when it's on and booted, what is the screen showing? More importantly is the backlight on at all or not?

So in situation 1 and 2 from my original post the pi boots up and works normal except for the noise. Situation 3 is when the screen does not show anything. It looks like the backlight does come on.

Can you rework the 3.3v and vcc solder points on the Pi itself. So the pins in the far right corner (the square ones and the ones below it)?

Also can you add a little more solder/rework these PINK pins? https://github.com/geebles/Super-AIO/wi ... lay-at-all

When I say re-work, I mean add some solder to reflow it. Don't use a solder sucker or try and remove the board!

This was one of the first things I tried. I reworked most of the pi zero-to-Kite board pins.

There is a reset button on the board, when booted and you hold this button down, does the screen come to life?

I tested this before I left for work, when I have the unit plugged into micro USB power ONLY (no battery plugged in) the screen gradually goes full brightness then goes back to normal brightness and shows nothing (but it looks like the screen is energized but displaying nothing). When I press and HOLD the small tactile RESET button on the SAIO board the display shows the normal retropie boot up screen then eventually fades and resets and repeats. When I release it shows nothing.

Lastly I assume you have tried another SD? Long short but a fresh image on a new SD is always a good start, but I can see from your pics the pi has booted (USB LED, and PI ON LED)

I will try this when I get home.

[Metalman1661]

Soldering looks good, does anything get hot? For example on the Pi itself or to the left of the LCD connector (D3/L2/U5)?

D3/L2/U5 were not hot after letting the unit run for 20 minutes with micro USB plugged in and battery charging. The pi zero cpu was hot to the touch and the chip on the small blue board (below to the left of the pi zero) was hot to the touch as well. Pictures attached are of the two chips.

Lastly I assume you have tried another SD? Long short but a fresh image on a new SD is always a good start, but I can see from your pics the pi has booted (USB LED, and PI ON LED)

Symptoms 1, 2, and 3 are still the same with a fresh image on a new SD card. See video for symptom 3 when pressing the tactile RESET button.

https://vimeo.com/254938266

[kite]

Hm odd, temperatures seem ok then, as long as it doesn't actually burn you then it's fine things being warm is good. Can you correct me if I'm wrong, but you're saying that in normal use it's ok and works fine, but when you plug USB in only it turns on (when it shouldn't)? Sorry I'm just a little lost on where the issue is if all still confusing or not behaving right it might be a good idea to email me and we can sort out a return and I can take a look and repair (sounds like if it just happened randomly in use that something hardware wise has failed so it'll be 'on the house' )

PS high pitch squealing is usually from an inductor, suspects are the one next to the backlight ... adjusting the brightness with MODE button combo may make it change?

[Metalman1661]

Hm odd, temperatures seem ok then, as long as it doesn't actually burn you then it's fine things being warm is good. Can you correct me if I'm wrong, but you're saying that in normal use it's ok and works fine, but when you plug USB in only it turns on (when it shouldn't)? Sorry I'm just a little lost on where the issue is if all still confusing or not behaving right it might be a good idea to email me and we can sort out a return and I can take a look and repair (sounds like if it just happened randomly in use that something hardware wise has failed so it'll be 'on the house' )

PS high pitch squealing is usually from an inductor, suspects are the one next to the backlight ... adjusting the brightness with MODE button combo may make it change?

So the two temperature items in my last post were hot enough for me to pull away after 5 seconds or so of holding my finger on it. So they were definitely in the HOT category.

Basically here are the problems I am having so far:

1. When plugged into micro USB and battery plugged in I hear a squealing sound. Also note I have the brightness turned all the way down and when I turn the brightness up it does go away some.
2. When i have micro USB plugged in ONLY, the display behaves as in the video of my last post. It does not show anything ( i do see backlight) but I hear the pi zero booting up in the background (splashscreen sound) . When I press the RESET button on the kite SAIO board it displays the correct image and when I release it disappears (as in the video).

It seems the squealing is only happening when the battery is charging and the unit is on at low brightness. When I have the unit off and micro USB plugged in charging the battery I do not hear the sound.

These two items above weren't present when I first built this unit and only recently came about. The squealing I can get used to but the other item prevents me from using micro USB plugged in without a battery.

[kite]

Ok, so the backlight is controlled by a 1KHz PWM signal, full brightness = no PWM (as it's fully on).. it could be that when lowering the brightness there is something in the charger/board that squeals because it is resonating with the 1Khz on the line somewhere, nothing to worry about! But the lower the brightness the louder it will be.

As for the other issue, how likely are you going to be running it without a battery? Running without a battery is potentially problematic as the USB power path isn't very powerful and so doing a lot of work will potentially brown out the Pi anyway (causes a reboot). If unlikely then that's no problem right?

The fix may be more involved to do, it's strange that you see that behaviour without the battery attached only.. this was fixed in later versions of the board.. for example the following MAY work however it may have side effects!!!

edit line:
https://github.com/kiteretro/Super-AIO/ ... D.ino#L112

and CHANGE to:

Code: Select all

pinMode(RESET, OUTPUT);
digitalWrite(RESET, HIGH)