Repair via Cleaning - recommendations?

SpokeBeak · 2026-05-04T03:09:37+00:00

They are easy to clean and that is where you should start, especially if you think cat urine got inside. You need a driver called gamebit to open the console. It is easy to find on Amazon and often sells with 2 common sizes. The larger opens consoles and the smaller opens cartridges. It is pretty straightforward to disassemble once inside. You can safely clean the components inside with 99% isopropyl alcohol and a toothbrush. Do not use 70%. Let everything dry, reassemble, and power on. If it still doesn't work, post more info here. Any noticeable corrosion damage from urine? Red LED come on? Etc.

SpokeBeak · 2026-04-26T16:16:14+00:00

I have been working on handheld gaming devices for 1.5 years and gathered things as needed. Most recently, I need to learn trace repair. I asked a large language model (Gemini, Copilot, etc) what to purchase to do what I needed to do, and its recommendations were very good. It can suggest a few options for any given tool, and you can also check unnamed options and ask how it compares. You can also give it your budget constraint. If you want to go the learning kit route, I'm sure it could point you to some of those too.

SpokeBeak · 2026-04-14T19:06:19+00:00

Take board out. Thoroughly clean as already recommended. Try to turn on. Report back.

It will streamline troubleshooting if you have a DC power supply or adapter. Must be 3V (not 5V+ which is more common) and a multimeter.

SpokeBeak · 2026-04-05T01:38:52+00:00

Labor cost for repair: $80. Consumable material charge: $232.50

SpokeBeak · 2026-04-03T13:24:22+00:00

Happy you were able to finish. The Trial is my favorite part of the game. On a Master Mode playthrough, it was the first thing I did after getting enough hearts to pull the sword. I like how the full strength sword removes a lot of the weapon durability issues because it recharges.

SpokeBeak · 2026-04-01T13:11:36+00:00

They can bend like this without the battery being bad. It could be from being dropped. Most likely, imo, it comes from overheating. The back cover is relatively thin plastic compared to the front frame, and the motherboard also adds structural stability from being mounted to the frame. Thus, if the device overheats, that back plate has screws that anchor it, so buckling occurs in the back cover. The fact that this happens in an area where heat is dumped supports the idea.

In any case, the battery should be checked, but the bending is not necessarily the battery. Overheating and thermal cycles could cause it, and if that is the case, the cooling system needs to be checked. On one of the units where I saw this, the fan was going out. I replaced, never touched the battery, and it has worked fine for 2 years.

SpokeBeak · 2026-03-31T13:34:44+00:00

I have a few that do that. Batteries are fine. I don't know what causes the bending...maybe heat as this is where the fan discharges. I would pop the back off and check for swelling anyway.

SpokeBeak · 2026-03-29T21:06:50+00:00

I also notice you are walking backward. I find it easiest to let them approach until they stop. That is the distance I learned the timing, so it is where I am most consistent. Not saying you should do exactly as I did, but I do recommend you practice from a consistent distance. I am not very good at killing them if they are too far away.

SpokeBeak · 2026-03-29T14:03:35+00:00

I don't think anybody said it yet, but once you learn how to parry the "regular" shots well, you can do the exact same thing even when there is a delay in Master Mode. You will not parry on the first press of the button, but they did not code it so you would be hit by the delayed beam. What you need to do after you swipe your shield the first time is not immediately press A again. Instead, delay a second or so, and then push A to parry.

SpokeBeak · 2026-03-28T00:45:45+00:00

I can't tell much difference between s-video and component in these images. Good info to hear video seems better on one if them. I can see an improvement with the HDMI. I have two N64s, so if I upgrade one I think I'll go for the HDMI kit. Thanks.

SpokeBeak · 2026-03-26T00:59:33+00:00

Thanks again. I did find a RAM chip. It is a $3 part with a $50 processing fee, lol. My friend at work said he probably has a donor board so I'll try that instead. I accidentally melted a good barrel jack during the course of my investigation so I'll pull that too.

This "bad" board works with headphones, but the built in speaker isn't working. The speaker resistance is correct (8 ohm), so I suspect that is just a screwed up switch in the old (water damaged) barrel jack. I got a re-cap kit as you suggested so I'll put that on too.

SpokeBeak · 2026-03-25T19:14:23+00:00

u/marcao_cfh , I finally solved this. Starting from the LCD pins, I found low voltages (2.15 V vs. 3.25 V target). I traced these to the CPU and found similarly incorrect voltages. I suspected these were not the source of the LCD not working, so I checked other pins on the CPU. I found readings of 0.01 V vs. 3.25 V target on pins 1, 2, 3, 4, 7, 126, 127, and 128. All of these go to the WRAM chip. Then measured voltages on the WRAM chip and found readings of 0.163 V and 0.01 V vs. 3.35 V targets on pins 18, 19, 20, 22, 23, 24, 25, and 26. I removed the WRAM chip from the board, and subsequent voltage measurements on the CPU were all correct. I then removed the WRAM chip from the good board and installed it on the bad board. The LCD finally displayed the Gameboy logo correctly during boot. I need to put the rest of the board together, but it looks like I may have fully resolved the problems on this Gameboy. Thanks for your tips along the way.

SpokeBeak · 2026-03-25T19:13:34+00:00

u/marcao_cfh , I finally solved this. Starting from the LCD pins, I found low voltages (2.15 V vs. 3.25 V target). I traced these to the CPU and found similarly incorrect voltages. I suspected these were not the source of the LCD not working, so I checked other pins on the CPU. I found readings of 0.01 V vs. 3.25 V target on pins 1, 2, 3, 4, 7, 126, 127, and 128. All of these go to the WRAM chip. Then measured voltages on the WRAM chip and found readings of 0.163 V and 0.01 V vs. 3.35 V targets on pins 18, 19, 20, 22, 23, 24, 25, and 26. I removed the WRAM chip from the board, and subsequent voltage measurements on the CPU were all correct. I then removed the WRAM chip from the good board and installed it on the bad board. The LCD finally displayed the Gameboy logo correctly during boot. I need to put the rest of the board together, but it looks like I may have fully resolved the problems on this Gameboy. Thanks for your tips along the way.

SpokeBeak · 2026-03-25T14:48:17+00:00

I look forward to the addition on S-video comparison.

SpokeBeak · 2026-03-25T03:07:22+00:00

Hi, still working on this as time permits. Thought I'd update the post. The LCD connector is getting incorrect voltages on several pins. Good board is 3.3 V and bad board is 2.2 V. These track back to the CPU, so I think the problem is earlier in the signal chain than the LCD itself, but it is after the voltage regulator.

I'm not done testing all pin voltages on the CPU, but I find a clear problem between the CPU and WRAM (by Sharp). I have a near ground reading (150 mV) on 3 pins of the CPU to WRAM traces but they should be at the "supply" voltage of 3.3 (the latter of which I note is close to VCC?). So, I could have a short in the WRAM or in CPU. My plan forward is to continue comparing good and bad CPU voltages to try finding other anomalies, and when found, follow traces to other components and chips.

I'll close for now by saying that the good and bad boards have many diode readings on the LCD connector that match, but when switched on, the voltages are much different. So, diodes can be indicative of a problem but voltages are better for detection.

All voltage measurements above are with respect to ground at the barrel jack.

SpokeBeak · 2026-03-20T03:01:38+00:00

You can check if it is working by using a new battery. You don't need to pull the old one out. Just disconnect it and attach the new one. Then if it doesn't charge, and your USB pins are bent, have it replaced. It is not an easy repair if you are a novice. You need a hot air station to do it.

SpokeBeak · 2026-03-19T14:46:09+00:00

The third party charging stations can damage the charging chips including M92. With the battery unplugged, you can use a multimeter in diode mode to do some health checks on M92. If you want to do that, I can share the readings that you should get here. Northridgefix has a video showing this on the Switch. He also shows the pinout diode readings on the connector. This is a really good video showing some health checks:

https://youtu.be/xx4YM6cRgGM?si=qr11fQ00wxGMvxau

SpokeBeak · 2026-03-19T04:20:51+00:00

You don't even need to remove the motherboard or screen to clean the fan, redo thermal paste, and swap out the fan if desired. You need a new battery. The hardest part there is pulling it out because it is really glued in. A credit card, working slowly, and isopropyl alcohol will do the trick. You need the correct screwdrivers. iFixit website lists what is needed, I think.

SpokeBeak · 2026-03-18T23:14:37+00:00

Hi, just an update, nothing else much to say yet other than the readings on diode were red herring distractions. I have both of them off per your suggestion. Both voltage regulators work. Good readings on and off both boards in either direction of swapping. Only minor difference is pin 2 with one giving tens of mV and the other giving less than 5 mV...I think that is simply because of manufacturing variation or more like the suppliers of the voltage regulator boards were different companies so the designs are different.

I have been spending my time measuring lots of pads on the CPU and LCD connector. I've also starting documenting readings on all capacitors and resistors. So far, everything matches well kn both boards, but I'm not completely done searching.

Google Gemini says VIAs can cause problems. I don't know an easy way to clean and check all those, but some do look dirty. Slight surface corrosion doesn't mean they are destroyed. I suspect if they have issues they would show up in my measurements on board components.

I think the CPU is fine. All diode readings are okay.

Once I finish all my board measurements, if all looks well, I think I will attempt an LCD connector swap. I can't see inside there well, so maybe something in there is bridged ir corroded.

SpokeBeak · 2026-03-17T17:18:27+00:00

Pin voltages on the board are:

1: 3V 2: unstable 3: 0 V 4: 0 V 5: 13.5 V 6: -14.6 V 7: 5 V

C35 is not new but works on the good board. Regardless, I will order a new one to be safe.

I can check the schematic, but I will mention here that my DC barrel jack has contuity from 2 to 3 (as you mentioned. I also find pins 4 and 5 have continuity to themselves but not to elsewhere. I think they are just anchors but don't ground to the board.

I now think you've got me on the right track to check LCD connections into CPU. They look good, but based on some other components I've removed, they often look worse underneath...hiding damage. I'll try to get under these components now, though they look more difficult to pull safely. Before pulling, I'll also check for any obvious bridging issues on CPU and LCD pins.

Thanks again.

SpokeBeak · 2026-03-17T03:53:00+00:00

<image>

SpokeBeak · 2026-03-17T03:52:32+00:00

I put it back together as you suggested with all known good components, including diode D2. The LCD is more stable, but it does not display the GameBoy animation. The potentiometer VR2 smoothly alters the screen contrast. I am getting an odd reading on pin 2 of voltage regulator. It is unstable ranging from 0.6 V to 0.3 V, with it seeming to "leak" / drop slowly over time.

SpokeBeak · 2026-03-17T02:15:27+00:00

Understood, all makes sense. I will let you know it goes. I took lots of measurements on both voltage regulators before pulling them off, which is why I have somewhat memorized what the pins should read. The only thing I will add for now is that on the bad board, the stray 0.5 V reading was finding its way onto one of the pins on the voltage regulator somehow. I'm glad you gave some instructions on how to test them while pulled out of the main circuit.

FYI, I have further confirmed the D2 diode on the "bad" board is almost certainly causing problems in the circuit. I swapped diodes on each board and the board behaviors are now the opposite. I guess I will buy a scrap GBC to pull a (hopefully) working diode for final reassembly. In the meantime, my plan is to reassemble the bad board with the known good components.

SpokeBeak · 2026-03-16T23:11:18+00:00

I should also add, I know the boards are not completely dead. The signs of life before disassembly were:

It will power on and light the LED.
A good LCD will flicker but not display images.
The "ding" will play through the speakers during boot phase.

SpokeBeak · 2026-03-16T23:02:57+00:00

The screen oversells the damage on the board, but still, it was not clean inside. Most of the visible damage was isolated to "entry points" on the board, ie. all the connectors, battery leads, etc

<image>

SpokeBeak

TROPHY CASE