pin2dmd color problem

[darden78]

hi guys, i need your help.

Yesteday i put a stepdown in a pin2dmd but i forgot to set it to 5v, it was 11,8. It blinked 3 times before i realized what happened and turned it off.

Putting the correct 5v, the result is the one of the picture.

It's an old discovery version. Testing the involved components i firstly changed the discovery with a different one and it worked good, that means it's not the shield and the panels, so i connected the old discovery to a different shield/panels and it does it again.

 

Now what i know is:

the problem is on the discovery,

it's just in the lower half of the pin2dmd

it involves just the green colour, it seems it's always on and never turns off.

 

Do you have an idea of the components i have to check on the discovery?

Because (except for the green dots) it works fine, that means the chip is ok.

Any idea?

thank you

[lucky1]

The STM32F407

[darden78]

so you think it's a chip problem?

should i throw it away or you think i can try to get it back?

[lucky1]

If you are sure that it is the discovery board, the output pin for green of the lower part of the display seems to be always on.

Check the pinstate of PIN 5-7 (R2-G2-B2) on the HUB75 connector. Those pins go directly to the STM32F4 cpu.

[darden78]

2 hours ago, lucky1 said:

If you are sure that it is the discovery board, the output pin for green of the lower part of the display seems to be always on.

Check the pinstate of PIN 5-7 (R2-G2-B2) on the HUB75 connector. Those pins go directly to the STM32F4 cpu.

yes, i'm sure it's a discovery

and

yes, i'm sure the green leds on the lower part of the display are always on.

 

but i don't know how i can test the pinstate.

What do i have to do to test them? just check if there is continuity?

look at the output voltage?

or what?

thank you

[lucky1]

Use a oscilloscope