| Region
|
Model
|
Standard
|
System
|
| America
|
MK-3006
|
NTSC
|
M
|
| Canada
|
MK-3006-22
|
PAL
|
B (VV)
|
| Australia
|
MK-3006-03
|
PAL
|
B (VE)
|
| New Zealand
|
MK-3006
|
PAL
|
D
|
| China
|
MK-3006-15
|
PAL
|
G
|
| Germany
|
MK-3006-18
|
PAL
|
G
|
| France
|
MK-3006-09
|
SECAM
|
RGB
|
| Board Revision
|
Part Number
|
Standard
|
Notes
|
| IC BD M4Jr. VA1 (837-7275)
|
171-5926-A
|
NTSC
|
-
|
| IC BD M4Jr. PAL
|
171-5922A
|
PAL
|
-
|
| IC BD M4Jr. PAL 2M
|
171-6395A
|
PAL
|
-
|
| IC BD M4Jr. VA1 (837-7275 RGB)
|
171-5926-A
|
SECAM
|
There is no RF modulator or composite video signal on this board (it outputs an RGB video signal only).
|
IC8 delivers the main +5V DC reference voltage (also referred to as VCC) for the whole board.
So yeah, we better make sure it works flawlessly 😄
| Steps
|
- Measure the input voltage VI. Voltage must be
≈ +8.3V DC[note 1] on this pin.
- Measure the output voltage VO. Voltage must be
+5V DC.
|
| Problem
|
Solution
|
| Nothing (0V) on VI
|
- Ensure the power switch wasn't OFF during your check (it happens to the best of us).
- Test
D2 diode.
- Test power switch (both positions and
GND).
- Power switch isn't faulty? Multiple options here:
CN4 barrel socket could be faulty, check solder points.- On 171-6395A/171-5922A:
- Test
C41 capacitor. Visual check for any bulging first.
- On 171-5926-A:
- Test
C50 and C52 capacitors. Visual check for any bulging first.
- Check
JV and JG ferrite beads for continuity and absence of high impedance.
- PCB trace is cut.
|
| Nothing (0V) on VO
|
- Ensure the power switch wasn't OFF during your check (it happens to the best of us).
- Check continuity:
- On 171-5926-A:
- Between the input pin
VI and positive pin on C50.
- Between the center pin
GND and the ground plane.
- Between the output pin
V0 and C52.
- On 171-6395A/171-5922A:
- Between the input pin
VI and positive pin on C41.
- Between the center pin
GND and the ground plane.
- Between the output pin
V0 and CP resistor right next to IC8.
- In some rare cases, the component pads could be busted.
- Still nothing? The voltage regulator is faulty, replace the component.
|
| More or less than 5V DC ± 5% on VO
|
|
Virtually any 7805 (TO-220) will do the trick[note 2]
Troubleshooting power delivery[edit | edit source]
The idea here is to ensure every IC is powered correctly by checking every "voltage in" pins.
Check for VCC (+5V DC) presence on:
| 171-5926-A
|
171-6395A/171-5922A
|
- Pin 11 on
IC1.
- Pin 28 on
IC2.
- Pin 28 on
IC3.
- Pin 32 on
IC4.
- Pin 18 and 60 on
IC5.
- Pin 28 on
IC6 and IC7.
- (NTSC only) Pin 12 and 19 on
IC9.
|
- Pin 11 on
IC1.
- Pin 28 on
IC2.
- Pin 26 on
IC3.
- Pin 48 on
IC4.
- Pin 18 and 40 on
IC5.
- Pin 28 on
IC6 and IC7.
- Pin 12 and 19 on
IC9.
|
| Problem
|
Solution
|
| +5V DC missing on a pin
|
There is no magic answer here:
- Follow the via (or the schematics if you have them) until you find the culprit.
- If every component is OK between
VCC and your pin, the PCB trace is cut.
|
Troubleshooting the RESET circuit[edit | edit source]
The RESET circuit is active low (active at 0V); Any continuous 0V level will trigger a reset loop and prevent the board from initializing.
That's why we need to check for VCC (+5V DC) presence on every RESET pin.
Check for VCC (+5V DC) presence on:
| 171-5926-A
|
171-6395A/171-5922A
|
- Pin 26 on
IC1.
- Pin 41 on
IC4.
- Pin 23 on
IC5.
- Pin 46 on
CN1.
|
- Pin 26 on
IC1.
- Pin 46, 47 on
IC4.
- Pin 23 on
IC5.
- Pin 46 on
CN1.
|
| Problem
|
Solution
|
| +0V on one or multiple pins
|
- The most common issue is a faulty
C18/C2 capacitor.
- The
R3/R4 resistor could be faulty too.
- (171-6395A/171-5922A only)
IC4 is handling RESET IN and RESET OUT it could also be faulty.
|
Troubleshooting the clock circuits[edit | edit source]
| 171-5926-A
|
171-6395A/171-5922A
|
Waveform [note 3]
|
Check the clock on the XTAL oscillator, frequency should be 10.738635MHz ± 100Hz.
|
Check the clock on the XTAL oscillator, frequency should be 53.203424MHz ± 100Hz.
|
-
|
| -
|
Check for a 4.43361875MHz ± 30Hz on:
|
-
|
| Check for a 10.738635MHz ± 100Hz clock on:
|
Check for a 10.738635MHz ± 100Hz clock on:
- Pin 41 on
IC4.
- Pin 34/35 on
IC5.
|
|
Check for a 3.579545MHz ± 30Hz clock on:
- Pin 6 on
IC1.
- Pin 47 on
CN1.
|
Check for a 3.579545MHz ± 30Hz clock on:
- Pin 6 on
IC1.
- Pin 47 on
CN1.
|
|
|
|
IC BD M4Jr. VA1
|
IC BD M4Jr. PAL
|
IC BD M4Jr. PAL 2M
|
IC BD M4Jr. VA1 (RGB)
|
Function
|
| IC8
|
MC7805
|
L7805CV
|
L7805CV
|
LM340TS, L7875CT
|
Voltage regulator; produces VCC.
|
Transforms the output voltage produced by the AC/DC adapter (+9V DC ± 10%) to a reference voltage named VCC (+5V DC ± 5%) that will act as the main power rail.
|
| IC1
|
Z0840004PSC
|
Z0840004PSC
|
Z0840004PSC
|
Z0840004PSC
|
CPU
|
-
|
| IC2
|
MPR-12808
|
MPR-12808 (W63), MPR-12808F
|
MPR-15155 (T62)
|
MPR-12808 (W63)
|
BIOS ROM
|
Boots the system, handles the splash screen, anti-piracy and region locking and starts the game.
This ROM can also contain a built-in game (after the first 8KB dedicated to the BIOS).
|
| IC3
|
D4168C-15
|
D4168C-15-SG, KM6264BL-10, LC3664RL
|
D4168C-15-SG, LC3664BL-10
|
LC3664BL-10, HM6265L-90
|
RAM
|
General purpose SDRAM.
|
| IC4
|
315-5216
|
315-5237
|
315-5237
|
315-5216
|
I/O Controller
|
Interfaces with the gamepads and accessories.
|
| IC5
|
315-5246
|
315-5246
|
315-5246
|
315-5246
|
Video Display Processor
|
Commonly referred to as the VDP, it handles graphics and audio.
|
| IC6
|
D4168C-15
|
D4168C-15-SG
|
D4168C-15-SG
|
D4168C-15
|
VRAM
|
SDRAM dedicated to the VDP.
|
| IC7
|
D4168C-15
|
D4168C-15-SG
|
D4168C-15-SG
|
D4168C-15
|
VRAM
|
SDRAM dedicated to the VDP.
|
| IC9
|
CXA1145P
|
CXA1145P
|
MB3514
|
-
|
Video Encoder
|
Receives analog RGB and composite synchronous signals and outputs NTSC/PAL composite, luminance, chrominance and RGB video signals.
|
Master System II ground plane
What is the device power input?[edit | edit source]
- +9V DC ± 10%, 0.5A.
- 5.5mm x 2.1mm barrel plug.
Center-pin negative polarity (tip: +9V DC, sleeve: -9V DC).
Where I can find GND on the board?[edit | edit source]
The ground plane is present all around the board as a large copper via (see picture).
- ↑ Why not +9V DC here?
VIN goes through a diode D2 before reaching IC8. D2 is a silicon diode rectifier, and they always have a forward voltage drop (≈ 0.55V at 0.5A for a 1SR35-100). stock IC8 can operate with a voltage as low as +7V DC, so we're good.
- ↑ Want to pick your own voltage regulator?
- You may want to choose a TO-220 package if you want a drop-in replacement (same pins and pitch).
- Make sure the pinout is correct (
VI, GND, VO).
- The regulator must provide a +5V DC nominal output voltage
VO.
- And accept a +9V DC input voltage
VI (check the minimum and maximum input voltages too).
- It's advisable to double-check the dropout voltage
Vd (The difference between the input and output voltages for the voltage regulator to work).
We have a +4V DC difference between VI and VO in our context, so we need to make sure the dropout voltage is lower than +4V DC.
- IC8 will provide a critical reference voltage: keep the tolerance as low as possible ≤5% (the tolerance is the output voltage accuracy).
- Keep the junction-to-air thermal resistance (usually named
θJA) as low as possible.
- ↑ Don't buy an oscilloscope to check the crystal oscillator if you don't already own one! Desolder the oscillator and measure it with the frequency function/mode on your DMM will do the trick.
