Nintendo DS Lite
First look

March 11, 2022

As it came to me, the DS cartridge slot would not read games and it was marked as 'For parts'.  I wanted to see if I could at least bring it to a useable state, and from there consider a shell swap.  The first step was to try powering it on, just to confirm the problem.  Years in the IT industry taught me to 'trust but verify' when it comes to issues reported with equipment.

Overheat shot of a crimson Nintendo DS Lite, with the top showing a number of scratches.

The case has already been cleaned to remove a Disney Cars sticker from the top, but you can see the scratches and notable scuffs at the corners.  Luckily the inside looked decent.

Before trying a cartridge, I wanted to look at the slot itself.  Bent pins would be a sure indicator that it wasn't going to work, and if there was anything gumming up the slot there would be no point in putting a cartridge in and compounding the problem.  So, a peek into the slot and...

Cartridge connector from Nintendo DS Lite showing the internal pins.

With the visual all clear, I inserted a cartridge to see if anything would come up, but the problem was confirmed, the cartridge was not being read.  I didn't want to try swabbing the pins because it could get caught and cause damage, so instead I tried some contact cleaner and then I used a low value cartridge to exercise the slot.  After letting the slot dry out thoroughly, I turned on the DS to see if it would read the cartridge.

Success!

Next it was time to test the functions starting with the buttons.  There is a nice homebrew utility called Diagnose which can be used to test many aspects of the DS.  I cycled through all of the buttons using the button test and found that both the left and right shoulder buttons were dead, but everything else worked.

Nintendo DS Lite screen capture from the Diagnose app for diagnosing controls.

The button test screen from Diagnose.

Carefully opening the DS I could see the first issue, which was the pin which seats the left shoulder switch was completely missing.  I was able to find a suitable replacement pin which after being filed to shorten it, fit quite nicely.

Nintendo DS main board showing the bumper button area.

The left shoulder button with the new pin in place.  When reinstalling these, the spring needs to face the right way to resist the button press, and the end of the spring needs to sit in the channel below the pin.

For the right shoulder switch the problem wasn't a missing pin, but rather it was likely that the spring contact in the tactile switch had oxidized over time.  YouTube has a video by The Fix which shows one approach to cleaning the spring contact.  Since I didn't have any replacements on hand I decided to try the delicate process to refresh the contact.  The procedure involves shifting the metal face which holds the tactile plunger in place, removing the plunger and then removing the cleaning the spring contact.

Nintendo DS Lite main board showing the tactical switch for a shoulder button.
Nintendo DS Lite main board showing the tactical switch for a shoulder button with the plunger removed.
Plunger and spring contact from a Nintendo DS Lite shoulder switch.

I managed to extract the plunger and the contact, and then when scraping the spring somehow managed to shoot it into the air, resulting in a search and rescue mission.  Then back to cleaning and sproing... gone again.  I found it once more and finished the cleaning but then realized that the subtle depression which enabled the spring force was deformed.  I used tweezers to try and recreate it as best as possible, and then reassembled the switch, breaking off the metal retaining plate in the process.  From there I resoldered the faceplate, and managed to get it all back together.  I reassembled the DS and performed another button test.  Better.  The right button would at least register now, but it required a strong press and it certainly wasn't clicky.

Nintendo DS Lite screen capture of the Diagnose app showing the control testing screen.

That's where I should have stopped, but, not satisfied with the performance I took apart the DS and the switch again to see if I could better reform the spring.  Looking around the desk I found some RCA style connectors which had a nice smooth round pin which was the same size as the spring.  I pressed the pin into the spring and ended up with something that was a little more 'springy'.  The bench test suggested it was an improvement and then I reassembled the DS and tested the button but unfortunately now the button didn't work at all.  Something had gone wrong with the reassembly.  Open back up, open switch, pull out parts, check, reassemble, repeat.  No joy, something was wrong, likely the reforming just wasn't the right depth for the switch.

In the end I really want the switch to feel great, not just OK and so I decided to order a batch of replacement switches.  Since I was placing an order of parts anyway I thought I might as well order a replacement shell.  After all, when I was finished I really wanted this thing to look excellent, and work perfectly.  Now I wait for the parts.

They arrived!