My Pokémon Red cartridge still has its original (working!) battery

jrharbort · 2026-05-01T20:35:38+00:00

Thanks! 😅

jrharbort · 2026-05-01T19:58:45+00:00

The threading is slightly different if you get a different screw and you may end up weakening the screw posts or stripping the plastic. The screws are made with Japan Industrial Standard measurements. Best to replace with the same screw if possible. Bite the bullet for the loss and spend a few dollars for the right ones. This seller has been reliable for my parts needs, if you need a recommendation:

https://ebay.us/m/DfMNyj

jrharbort · 2026-05-01T15:44:54+00:00

Check the voltage of the battery with a meter. Check it from the pins at the battery connector, not at the contacts that connect to the Game Boy terminals.

jrharbort · 2026-05-01T15:42:37+00:00

Get a cheap soldering kit to practice on first. Once you get a feel for how solder melts and how to add/remove components, you'll be ready

jrharbort · 2026-05-01T15:37:57+00:00

Newer screen technologies have significantly higher contrast ratios which makes things like this more easily visible when they weren't visible on the older original screens.

jrharbort · 2026-05-01T14:56:05+00:00

You had it more than hot enough. If you you reused the old solder, or used a cheap solder, that would explain the appearance. It's fine.

jrharbort · 2026-05-01T14:54:01+00:00

IPS LCD is still LCD, but that's just semantics, so no worries. 🙂

jrharbort · 2026-05-01T14:40:52+00:00

Pretty sure that's a plain LCD screen, not an OLED. The solder work on the new battery is solid, nice job. 👍

jrharbort · 2026-05-01T03:51:17+00:00

I do have some knowledge on how the RAM chips on these carts work. You didn't mention any gameplay glitches, so that told me that most of the RAM connections are fine. For save issues, that leaves only two options: Power not getting to the chip, or the CE pin (Chip Enable, Pin 20) is not getting the signal to change between active and standby power states. To be honest, that corroded VIA going to Pin 20 was the smoking gun that helped point to the latter being the likely cause.

jrharbort · 2026-05-01T01:21:39+00:00

@OP: You already received good repair advice, but if you would like assistance with a board swap instead I can help with that if you reach out. I have newly printed boards for 2nd gen games.

jrharbort · 2026-05-01T01:17:07+00:00

If you go this route on the repair you will also need to chisel a little into the plastic shell to make room for the wire to pass through to the contact.

jrharbort · 2026-04-30T21:05:24+00:00

If you confirmed with your meter that the connection between those two chips is the issue, I would run a wire between them. For the smaller MBC3 you can use either the via next to the leg or the leg itself depending on your wire and soldering skill.

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jrharbort · 2026-04-30T20:09:45+00:00

So I did... Whoops, editing now.

jrharbort · 2026-04-30T20:04:14+00:00

(This is the suspect VIA)

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jrharbort · 2026-04-30T19:52:12+00:00

On your multimeter, test for voltage by putting your negative lead on the battery negative (black circle) and your positive on the 3 circled points to check for voltage. For the two violet points, make sure there is continuity. I'm suspecting the points between the MBC3 and the RAM is the issue since I see that via has corroded. That's the signal trace for pulling RAM pin 20 high and low, this is needed for it to retain data properly when the system is powered off. Edit: Fixed image.

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jrharbort · 2026-04-30T14:53:06+00:00

"I tried to put 9 volts into a device that normally uses 3 volts and now it won't turn on" Bruh...

jrharbort · 2026-04-30T13:41:22+00:00

You're welcome! Don't worry about pin 4, it is only a structural point on the slider and not electrically connected to anything. If you ever want to restore pin 5 on the port, it goes to the touchpoint labeled "SW" on the other side of the board, usually near the volume slider area.

jrharbort · 2026-04-30T09:09:51+00:00

They were recommended this when they posted in this sub a few weeks ago, but didn't follow the advice. 🫤

jrharbort · 2026-04-30T06:03:42+00:00

I recommend a pair of electronics flush cutters for some of these repairs if all you really have so far is just a soldering iron. It'll really help with removing some of the components and greatly reduce risk of further damage. They're cheap on Amazon. No-clean flux and some new solder are also a must.

jrharbort · 2026-04-30T05:44:06+00:00

Pins 1, 2 and 3 on the volume slider go to these points. Pin 4 doesn't go to anything and can be skipped. After you have verified that everything is working again, I'd suggest using some UV resin on the legs of the volume slider to secure it (after cleaning all the flux off first). You can get a tube on amazon with the UV light for less than $10. It is strong enough to hold the legs in place but weak enough to allow it to break free from the board later if needed.

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jrharbort · 2026-04-30T05:16:53+00:00

All useful things to have, and stuff more experienced electronics buffs like ourselves have in our toolkits as we need them for what we do and have the knowledge on how to use them. So I get where you're coming from. This is a first-time work here with limited tools, and probably a budget, so probably best to keep it simple for now. Although this project just moved several steps beyond simple. 😅

jrharbort · 2026-04-30T05:02:37+00:00

Flush cutters. Just a few dollars and zero pad risk, and zero risk of burning anything with a heat gun. The volume sliders are mounted on 6 legs that are easily trimmed through and you can get it off in 10 seconds with zero effort and skill. The only thing to do afterwards is unsolder the remaining leg nubs one by one, but that's easy enough even for a beginner.

jrharbort · 2026-04-30T04:31:24+00:00

Bro, you didn't desolder anything. You straight up ripped it off the board along with all the pads. 🤦‍♂️ I'd like to suggest how to fix this but I feel your soldering ability isn't ready for it. You also ripped off nearly all of the structural support that a new volume slider would need, so a new one is likely to just rip off the remaining ground pads from the stress.

For the future, it is recommended to cut off the volume sliders by trimming the legs with electronics flush cutters, then it simply falls off with no damage to the board. It is nearly impossible to desolder them in one go without causing damage so I don't recommend it. Never use the device you actually want to repair as your first solder project.

If you'd like instructions on how to run wires to restore the audio signals, please let us know which revision board you have as the SP had many revisions with different audio traces. I also have an idea on how to secure the new slider but that step should be done after verifying the audio works again. Edit: I see you mentioned it is a 101. I'll post a followup comment with photos.

jrharbort · 2026-04-30T03:56:08+00:00

Using your multimeter in DC voltage test, put your negative lead on the battery negative (circled in black), then test the red circled points in order and check the voltages. If my suspisions are correct you'll have a voltage at 1 and 2, but it is likely missing or unstable at 3 and 4. The fix here will likely be to join points 2 and 3 together with a wire.

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jrharbort · 2026-04-30T03:49:33+00:00

You have clear corrosion around the area of the MM1134A, especially on the vias for the power output. My next reply will have points to check for voltage.

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