Hi, my name is Jonathan. I recently received my Meggy Jr kit and assebled it. Everything seemed to work fine. But then i noticed that the "walls" in revenge of the cherry tomatoes are light blue instead of white and the orange enemies are bright green. I also noticed that in some other games like collins DoT game, where the "sun" should be orange and yellow but instead is light green. I hope you can help me with that. Thanks, J.

Check all of your solder connections, and make sure that all chips and the RGB matrix are installed fully and in the correct direction.

For something white to appear bluish, and something yellow to appear greenish, means that you're not getting much in the way of red from the display.

I already rechecked all the solder connections but couldnt find any error. I also think that its caused by too less red, because the red "tomatoes" are really weak. Any idea which pin that could be?

Are ALL of the reds weak, or just certain rows and columns?

The schematic is available here: http://www.evilmadscientist.com/source/MeggyJrASchematics.pdf

If it's only certain rows or columns, you can use that schematic to trace the offending pins and check their solder or check to make sure that those chips and pins are fully inserted in the board.

However, since there isn't only one pin for Red, it sounds more like the RGB panel is not fully/properly seated on the board. It should be flush up against the top of the socket on both sides, for all pins. If you see any sort of gap, it's not inserted far enough, and may cause the issues that you're seeing.

Make sure the matrix display is fully seated, and if it isn't, try to fully seat it or remove it from the socket and try to seat it again. If it's hitting another component underneath it that ia preventing it from fully seating, then you may need to make sure that everything under it is installed properly first.

Hopefully Windell or someone else can help you out later on, but it's only 6:45 AM, on a Saturday, on the West Coast right now.

If the red LEDs are all on but very weak, it's likely that the current regulator for the red LEDs is not configured properly-- and the current set point is configured by a single resistor. If resistor R2 is not connected properly at both ends, both the red LEDs and the 8 yellow auxiliary LEDs will be very dim.

Hopefully Windell or someone else can help you out later on, but it's only 6:45 AM, on a Saturday, on the West Coast right now.

I'm actually at a conference on the east coast this weekend.

Hi. I resoldered both R2 and R1, but it had no effect. the red color isnt that weak, but also not as bright as the other colors. Any other suggestions?

The top and bottom walls are supposed to be white in color. If they are not, then something has likely gone wrong. There can't be that many things. Check also that both R1 and R2 are the correct value.

Check also the soldering at pin 23 of U3, which is the second to last pin on the corner of U3 closest to C4.

Unlikely, but check that the matrix display is correctly oriented, with the label facing towards the side with four buttons.

R1 and R2 are the correct value, pin 23 is nicely shiny and the matrix is oriented correctly. could it be a programming issue? i mean that the matrix is some sort of newer model and the code doesnt work correct with it?

One other thing to check is your batteries. If your batteries are running low, it can change the appearance of some of the colors. Start with fresh alkalines and see if that makes a difference.

could it be a programming issue? i mean that the matrix is some sort of newer model and the code doesnt work correct with it?

That seems highly improbable. So far, you've seemed to indicate that the program appears to be working correctly, just dim on the red elements, right?

One thing that you could try, as a test, would be to temporarily disconnect R1, and see if the logic appears correct to you.

Yeah, i checked the batterys and each one is on 1.5 Volts.
If i disconnected R1, what would that show me? I checked both R1 and R2 with my multimeter and they show exactly 1k ohm.
Thanks again for the help, J

Oh, and yeah the red elements are dim, which might be the cause of the "differing" colors.

So, you've been through the "obvious" things, and yet something is still wrong-- likely still a bad connection somewhere. There could be, for example, an accidental connection to ground somewhere that is loading down one of the chips and making it underperform.

Check out the schematic:
http://www.evilmadscientist.com/source/MeggyJrASchematics.pdf

For *every* pin of the two chips, U2 and U3, verify the connection. Put one lead of your multimeter on the "shoulder" of a pin on the chip, so that you know you're testing that pin, not just the part after the solder joint, and put the other pin at the thing you're testing connection to.

- Check each pin for connection to:
* VCC (measure at the 3-pin header jumper)
* GND
* The neighboring two pins.
- For pins that are supposed to be grounded, make sure that they are, with < 1 ohm resistance.
- For pins that are supposed to be connected through the resistor, make sure that there's 1k to ground.
- For the pins that are supposed to go to elsewhere-- to the matrix display or to the microcontroller -- make sure that they go there with < 1 ohm resistance, and with *no* connection to things that they aren't supposed to connect to.

kay, i dug through the schematics, checked every pin from the other side, couldn't find any bad solder joint or bad connection, everything was fine. The pins connected through a resistor are grounded with exactly 1k ohm the other grounded pins are grounded <1 ohm.
The pins connected to the matrix are also ok. (<1 ohm)

On each chip (U2, U3) there is just one pin connected to VCC and one connected to GND, right?

thanks, J.

The pins connected to the matrix are also ok. (<1 ohm)

What's important to check here is to see if there are *additional* connections between any of those points and GND or VCC, or possibly other pins on the chip. If one of those pins is hooked right to another, or to one of the power supply rails, then the chip could be badly strained, leading to what you see now.

On each chip (U2, U3) there is just one pin connected to VCC and one connected to GND, right?

No, pins 1 and 21 are connected to GND.