AGBM 11 (LiPo) Build Test Order

Under Construction

This is the order I would recommend building the AGBM-11. Because Lithium-ion batteries are generally dangerous, verifying you have built the board correctly is mandatory for safety purposes. This will also make troubleshooting MUCH EASIER! If you ask me why your AGBM is not working, my very first question will be "did you follow the build guide?" If the answer is no, I will direct you here (hello and welcome to anyone directed here in this manner).

Required equipment:

• Multimeter
• Power source (the USB port is convenient to use)

Notes:

• Remember to disconnect the power from the board while you're soldering! You can blow a fuse if you don't.
• For each step, if you encounter problems, the very first troubleshooting things you should do is check your soldering and check component orientations (if it has an orientation). Also, make sure you actually put all of the marked parts on the board.
• If you have success on one step, but after the next step you encounter issues, then you can be fairly confident it was one of the new parts you put on (or failed to put on properly) that's the culprit.

Step 0: Perform your Shell Cuts

The very first thing you need to do is cut the holes in your shell. Why? Because it's much easier to do this with a depopulated board. Follow the guide on the wiki and then come back here.

When you return, you should have a blank circuit board with the USB-C port connected.

Step 1: Protect the Button Contacts

Before starting, I recommend taping off the eight contacts for the D-pad, A, B, Start, and Select button contacts. Use kapton tape to keep solder off of the pads. (This isn't extremely necessary if you are adding tactile buttons instead, but still.)

Step 1: Lithium-Ion Battery Management System

The first and most important step for this board is making sure you've set up the lithium-ion battery management circuitry correctly. Do the back side parts before the front side parts.

Back side parts:

• J1
• C22, C66
• F2
• R28, R32, R33
• U19

Front side parts:

• D1
• F1
• Q4*
• R60

*Note: On board revisions from May 2026 (if your board does not have Q4, you can ignore this note): Q4 used to be a FET package, but is no longer needed. But, on boards that have Q4, pins 2 and 5 need to be shorted. So in place of the FET, a resistor array with two 0 ohm resistors fits well. It is only important that pins 2 and 5 of Q4 (the center pins) are shorted. If you want, all six pins on Q4 can be shorted without issue.

Test 1: Battery Checks

Plug in your lithium-ion battery (did you follow the LiPo Wire Preparation guide?). Use a multimeter to check the VCC test point to GND for battery voltage (between 3V and 4.2V).

Step 2: Charge Circuit

Now to add charging capability to your board. Remember to unplug your battery before you start this step.

Back side parts:

• PTC1
• R27, R61, R62

Front side parts:

• DL3

Test 2: Charging the Battery

Plug your battery in, and then plug in a USB-C connector. You should see the charging LED turn on. Once again, measure VCC to GND with a meter and make sure it reads 5V.

Step 3: Undervolt Lockout, VDD2 Generation

This step adds a big chunk of the power stage - the 2.5V supply as well as the bootloop protection circuit. And as always, remember to unplug the battery.

Front side parts:

• C1
• Q3
• R9, R11, R12, R16, R17
• U3

Back side parts:

• C2, C60
• Q1, Q10
• R8, R15, R24
• SW1
• U8

Test 3: Checking Undervolt Lockout, 2.5V Supply

Plug in the USB port. You don't need the battery for testing anymore! Now perform the following steps:

• Turn switch on, check this voltage:
  • SW to GND: 5V
  • VDD2: 2.5V
• Momentarily short circuit EN to GND without turning the switch off. Check this voltage:
  • EN to GND: 0V
  • VDD2: 0V

If EN doesn't drop to 0V and stay there after you remove the short, make sure you're actually shorting it with a good connection. If it still doesn't work, then at least you only have a few parts to check out. If you don't put the correct parts on for Q1 or Q3, then it won't work. Some 2N3904 and 2N3906 chips come with different pinouts than others, so make sure you purchased the correct ones. If you have your own, check the datasheets.

Step 4: Main Converter, Power LEDs

This will generate the 3.3V and 5V supplies. They turn on after the 2.5V supply is settled. I would solder the backside parts first, then the front parts.

For soldering the main converter chip, U5, I usually use a hot plate, but hot air can also be used. Do not attempt to hand solder this part - it will not work. This is not a challenge. You cannot do it and safely attach it to the board.

NOTE: Reminder to tape off the button contacts with kapton tape if using a hot plate.

Front side parts:

• C23, C30, C59
• DL1, DL2
• Q9
• R3, R4, R18, R29
• U4, U10

Back side parts:

• C10, C12, C21, C37, C40, C41, C42, C44, C61, C68, C72
• D2
• L1, L2
• Q5
• R7, R10, R13, R21, R22, R23, R25, R55, R58, R63, R64, R65, R66
• U5, U11, U14, U17

Test 4: Power Rails

Connect the USB port, turn the power switch on, and check the following voltages:

• VDD3 to GND: 3.3V
• VOUT5 to GND: 5V
• VAUD to GND: 2.5V

Check to make sure the green power LED turns on. If you have the ability to change the input voltage, try sweeping it from 3V to 4V to see if the color changes. It should go from green to red at 3.5V (when voltage is dropping) and should start blinking once it gets below 3.2V.

As a final test, short EN to GND to make sure power/LEDs shut off until the power switch is cycled.

Step 5: FFC Connector

Back side parts:

• P2
• R67
• VR1

Step 5b: CPU and RAM

Front side parts:

• C3, C4, C5, C6, C8, C15, C16, C34, C45, C46, C47, C48, C49, C50, C51, C52, C53
• EM7
• R1, R5, R26, R36, R41
• U1, U2
• X1

Test 5b: Screen test (GBC)

Step 5c: GBA mode

Test 5c: Screen test (GBA)

Step 6: Audio Circuitry

Front side parts:

• CP1, CP2, CP3, C24
• R37, R34, R53, R19, R20
• Q6

Back side parts:

• C9, C25, C26, C27, C28, C29, C31, C32, C33, C35, C36, C38, C54, C55, C56
• P3
• R14, R30, R31, R42, R45, R46, R47, R48, R49, R50, R51, R52, R54, R56, R57
• SP1
• U6, U7, U9
• VR2

Test 6: Audio Test

Test

Step 7: Cart connector

Front side parts:

• C7
• P1
• R2, R6, R38, R39, R40

Test 7:

Test

Step 8b: Tactile switches (optional)

• SW4 (x2), SW5 (x2), SW6 (x4)

Step 8a: the rest

Front side parts:

• C17, C62
• EM3
• SW2, SW3

Back side parts:

• C11, C13, C14, C18, C19, C20, C63, C64, C69, C74, C75, C76, C77, C78
• EM1, EM2
• P4
• Q8
• R35, R43, R44
• RA1
• U12

Step 8b: Optional the rest

Front side parts:

• C43
• Q2, Q7
• U16
• Z57, Z58

Back side parts:

• C39
• R68
• U15
• Z70, Z71

The Z Components

If you want L+R+Start+A and L+R+Start+B to replace touch inputs on screen kits, populate the Z components with the designated capacitors. If you want them to act as a regular button input, use the resistors/jumpers specified. See the Feature Configurations page for more info.