[Solved] Screen doesn't come on

My son and I just finished building our 8bitCADE XL’s and it was a blast! I very much enjoyed the process but one of the 8bitCADE XL’s screen does not come on at all. I have resoldered and fixed all the joints associated with the screen as well as any others that were less than perfect many times with no fix. Then I used the solder sucker to pull out the solder and start over on the screen joints this didn’t help either. The joints look very nice now but the screen still doesn’t come on. When powering on I can press “left, down, down, Button A” to enter the hardware test and everything else responds as it should. Is it possible this screen was faulty to begin with?

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Update: Decided to invest in a multimeter to measure the continuity. All 7 pins show continuity and beep right away. What am I missing? Is there another joint that could cause the screen alone to malfunction?

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Hi Randy,

I hope you are well! I noticed you also sent an email so I wanted to share the support and advice I gave to help anyone else who may be having a similar issue! Let me know how you got on!

I’m glad you and your son found the experience enjoyable!

I’m terribly sorry to hear about this, however, it does seem that the rest of your console is working as intended – which is great news!

Regarding your screen, if it is a faulty unit, I will be more then happy to send a new screen to you – no worries. With that said, it may not be a faulty unit and could be an issue somewhere on the board - so it’s worth taking a look! Could you send me a picture of the front and back of the console? This will help me get a visual of the board and give better, more accurate advice!

I love that you got yourself a multimeter! Taking yet another step into the world of electronics, super cool! I have attached the 8BitCADE XL schematic that will allow you to conduct accurate continuity tests – I hope this helps.

In most cases, the issue is to do with three things:

  1. A cold solder joint on either the screen or pro micro pins (it is definitely worth checking both components, however, you seem to have done this already!).
  • If there is a cold solder joint, then just reheat and reflow the joint. You may also need to apply a little bit more solder or, as mentioned, use the desoldering pump to remove the solder and reapply.
  1. A bridged solder joint causing a short circuit.
  • If there is a bridge, simply use the Desoldering pump to remove the bridge and reflow the joints. You can attempt to use your soldering iron to ‘split’ the joint however this can damage the PCB
  1. A scratch on the board that may have occurred when you were trimming the pins.
  • This could cause an issue with short circuits. If this is the case, shoot me over a picture and Ill take a closer look.

Regarding more specific advice, I will review the photos and get back to you as to what we will do next. I love that you are taking your own initiative to try and repair your console! However, your not alone! I’m glad you got in contact and hopefully, I can work with you to find a solution that works, as soon as possible!

My apologies for the inconvenience caused,

I hope this helps anyone else who may be experiencing a similar issue. Many of the issues that sprout up are due to soldering so definitely check your soldering!

I look forward to your reply,

Best regards,

Jack Daly
[email protected]

I had already purchased another oled, I was waiting to respond to see if that was the issue but it was not. Judging by what you said my best guess now is a scratch on the board due to me attempting to fix the issue in the beginning. Could have been a cold joint to begin with then upon going through and fixing joints the PCB could have been scratched by the soldering iron. I don’t know though that’s pure speculation.

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Ok, now that I have performed the continuity test the correct way. DC, MOSI and VCC do not show continuity. GND, SCK, RES and CS do show continuity.

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Hi Randy,

I hope you are well,

I have taken a look at the photos you sent and it seems:

^That this is the most likely cause of the issue. I have outlined below some of the bare copper tracks that could pose an issue to DC, MOSI and VCC

As you can see, the bare copper is where you may have scratched the PCB. This can cause short circuits and, if the track is split, no connection. This could be why you aren’t getting any continuity between the pins.

There are two ways to go around this:

  1. If the only issue is DC, MOSI and VCC having no connection (not that the VCC or any other pins have short-circuited with the GND etc) then you can try to connect wires between your screen and PCB (before mounting) to see if it works. If it does indeed work, then you can fit the screen back in and just solder wires directly between the Pro Micro and the screen (bypass the PCB).
  2. Alternatively, we can offer to send you another kit, at cost price, to replace it as the PCB is broken.

It is completely up to you. Either way, let me know and I will work with you to sort out any issues: if that be wiring the screen or getting a replacement kit.

As we are low on stock, I have kept a kit aside until I hear from you to ensure both options are available and there is no rush in your decision! I hope this helps.

I look forward to hearing from you, If you do have any questions, please feel free to ask! There is no rush.

Thank you kindly,

Best regards,

Jack