Quick Reference: Systems by Barrel Size
- 3.5 × 1.35 mm (centre-negative) – ZX Spectrum 16/48K, Atari 7800, Atari 2600 (VCS)
- 4.0 × 1.7 mm (centre-negative) – Sony PlayStation (PS1) only
- 4.75 × 1.7 mm (centre-negative) – Sega Game Gear
- 5.5 × 2.1 mm (centre-negative) – ZX Spectrum +2/+3, Sega Saturn, NEC PC Engine Duo, Sega Mega Drive 1, Sega Master System, Sega CD, Atari Jaguar, NEC PC Engine
- 4.75 × 1.7 mm (centre-positive) – Atari Lynx (1/2), Sega Mega Drive 2, Sega Nomad, Sega 32X
Table
Power Adapter Barrel Connector Compatibility Table
| System
|
Voltage
|
Current
|
Barrel Size
|
Polarity
|
Official PSU Model
|
| Group 1 – 9V DC, 5.5mm × 2.1mm, Centre Negative
|
| ZX Spectrum +2 / +2A / +3 |
9V DC |
2.1A |
5.5 × 2.1mm |
 |
Sinclair PSU (various OEM)
|
| NEC PC Engine Duo / TurboDuo |
9V DC |
1.5A |
5.5 × 2.1mm |
|
DUO-AC
|
| Sega Saturn |
9V DC |
1.5A |
5.5 × 2.1mm |
|
MK-2103
|
| Super Nintendo (PAL) |
9V DC |
1.3A |
5.5 × 2.1mm |
|
SNSP-002E(FRG)
|
| Nintendo NES (PAL) |
9V DC |
1.3A |
5.5 × 2.1mm |
|
NES-002E
|
| Atari Jaguar / Jaguar CD |
9V DC |
1.2A |
5.5 × 2.1mm |
|
PA-1400 / MK-4120
|
| Sega CD (Model 1 & 2) |
9V DC |
1.2A |
5.5 × 2.1mm |
|
MK-1602
|
| Sega Master System |
9V DC |
1.2A |
5.5 × 2.1mm |
|
MK-3025
|
| Sega Mega Drive / Genesis (Model 1) |
9V DC |
1.2A |
5.5 × 2.1mm |
|
MK-1602-05
|
| NEC PC Engine / CoreGrafx / TurboGrafx-16 |
9V DC |
0.85A |
5.5 × 2.1mm |
|
HES-ACA-01 / Turbo AC Adapter
|
| Group 2 – 9V DC, 3.5mm × 1.35mm, Centre Negative
|
| ZX Spectrum (16/48K) |
9V DC |
1.4A |
3.5 × 1.35mm |
|
Sinclair PSU
|
| Atari 7800 |
9V DC |
1.0A |
3.5 × 1.35mm |
|
C018187
|
| Atari 2600 (VCS) |
9V DC |
0.5A |
3.5 × 1.35mm |
|
C017945
|
| Group 3 – 9V DC, 4.75mm × 1.7mm, Centre Negative
|
| Sega Game Gear |
9V DC |
1.2A |
4.75 × 1.7mm |
|
MK-2103 (shared PSU with Saturn in some regions)
|
| Group 4 – 6V DC, 4.75mm × 1.7mm, Centre Negative
|
| Nintendo Game Boy (DMG-01) |
6V DC |
0.7A |
4.75 × 1.7mm |
|
DMG-03 / MGB-005
|
| Group 5 – 9–10V DC, 4.75mm × 1.7mm, Centre Positive
|
| Atari Lynx (Model 1) |
9V DC |
1.0A |
4.75 × 1.7mm |
 |
PA-1400
|
| Atari Lynx (Model 2) |
9V DC |
1.0A |
4.75 × 1.7mm |
|
PA-1400
|
| Sega 32X |
10V DC |
0.85A |
4.75 × 1.7mm |
|
MK-1633
|
| Sega Nomad |
10V DC |
0.85A |
4.75 × 1.7mm |
|
MK-1633
|
| Sega Mega Drive / Genesis (Model 2) |
10V DC |
0.85A |
4.75 × 1.7mm |
|
MK-1633
|
| Sega Nomad |
10V DC |
0.85A |
4.75 × 1.7mm |
|
MK-1633
|
| Group 6 – 10V DC, 5.5mm × 2.1mm, Centre Negative
|
| Nintendo Famicom (HVC) |
10V DC |
0.85A |
5.5 × 2.1mm |
|
HVC-002
|
| Nintendo Virtual Boy |
10V DC |
0.85A |
5.5 × 2.1mm |
|
VUE-002
|
| Group 7 – 5V DC, 5.5mm × 2.1mm, Centre Positive
|
| Neo Geo AES (later PRO-POW-3 / E) |
5V DC |
3.0A |
5.5 × 2.1mm |
|
PRO-POW-3 / PRO-POW-E
|
| Neo Geo CD (Front & Top Loader) |
5V DC |
3.0A |
5.5 × 2.1mm |
|
Neo Geo CD PSU
|
| Group 8 – 7.5V DC, 4.0mm × 1.7mm, Centre Negative
|
| Sony PlayStation (PS1) |
7.5V DC |
2.0A |
4.0 × 1.7mm |
|
SCPH-113
|
- Sega Mega Drive 1 vs 2: opposite polarity — swapping PSUs will fry the console ⚠
Notes & Warnings
- Mega Drive 1 vs Mega Drive 2 – opposite polarity; swapping PSUs will damage hardware.
- Sega 9V centre-negative group – Mega Drive 1, Master System, Saturn, Sega CD (cross-compatible).
- Nintendo PAL vs NTSC – PAL NES/SNES use 9V DC; NTSC variants use 9V AC (not compatible).
- Famicom & Virtual Boy – 10V DC centre-negative; only safe with each other.
- Game Boy DMG – 6V DC centre-negative; not compatible with 9V systems.
- Atari Lynx, Mega Drive 2, Nomad, 32X – 9–10V DC centre-positive; not compatible with centre-negative groups.
- Neo Geo AES (later) & Neo Geo CD – 5V DC centre-positive; not compatible with 9V/10V systems.
- General rule – PSU must meet or exceed system’s amp requirement; lower amps = underpowered.
Common Dangerous Mix-ups
| Mistake |
Why it’s dangerous
|
| Mega Drive 1 PSU → Mega Drive 2 |
Opposite polarity (centre-neg → centre-pos)
|
| Mega Drive 2 / 32X / Nomad PSU → Mega Drive 1 |
Opposite polarity (centre-pos → centre-neg)
|
| Any 9V PSU → Game Boy DMG |
Wrong voltage (needs 6V)
|
| 9V DC PSU → NTSC NES/SNES (AC) |
Wrong type (AC vs DC)
|
| 9V PSU → Neo Geo AES (later) / Neo Geo CD |
Wrong voltage and polarity (needs 5V centre-positive)
|
PSU Cross-Compatibility
Compatibility Key
| Symbol |
Meaning
|
| ✓ |
Safe – barrel fits, voltage/polarity correct, PSU current ≥ system requirement
|
| – |
Underpowered – fits & matches, but PSU current too low
|
| ✗ |
Dangerous – wrong voltage and/or polarity
|
5.5 × 2.1 mm barrel
PSU Cross-Compatibility Matrix — 5.5 × 2.1 mm barrel
System ▶
PSU ▼
|
ZX Spectrum +2/+3
|
Sega Saturn
|
NEC PC Engine Duo
|
Nintendo NES (PAL)
|
Nintendo Super NES (PAL)
|
Sega Mega Drive 1
|
Sega Master System
|
Sega CD
|
Atari Jaguar
|
NEC PC Engine
|
Nintendo Famicom
|
Nintendo Virtual Boy
|
Neo Geo AES
|
Neo Geo CD
|
| ZX Spectrum +2/+3
|
✓
|
✓
|
✓
|
✓
|
✓
|
✓
|
✓
|
✓
|
✓
|
✓
|
✗
|
✗
|
✗
|
✗
|
| Sega Saturn
|
–
|
✓
|
✓
|
✓
|
✓
|
✓
|
✓
|
✓
|
✓
|
✓
|
✗
|
✗
|
✗
|
✗
|
| NEC PC Engine Duo
|
–
|
✓
|
✓
|
✓
|
✓
|
✓
|
✓
|
✓
|
✓
|
✓
|
✗
|
✗
|
✗
|
✗
|
| Nintendo NES (PAL)
|
–
|
–
|
–
|
✓
|
✓
|
✓
|
✓
|
✓
|
✓
|
✓
|
✗
|
✗
|
✗
|
✗
|
| Nintendo Super NES (PAL)
|
–
|
–
|
–
|
✓
|
✓
|
✓
|
✓
|
✓
|
✓
|
✓
|
✗
|
✗
|
✗
|
✗
|
| Sega Mega Drive 1
|
–
|
–
|
–
|
–
|
–
|
✓
|
✓
|
✓
|
✓
|
✓
|
✗
|
✗
|
✗
|
✗
|
| Sega Master System
|
–
|
–
|
–
|
–
|
–
|
✓
|
✓
|
✓
|
✓
|
✓
|
✗
|
✗
|
✗
|
✗
|
| Sega CD
|
–
|
–
|
–
|
–
|
–
|
✓
|
✓
|
✓
|
✓
|
✓
|
✗
|
✗
|
✗
|
✗
|
| Atari Jaguar
|
–
|
–
|
–
|
–
|
–
|
✓
|
✓
|
✓
|
✓
|
✓
|
✗
|
✗
|
✗
|
✗
|
| NEC PC Engine
|
–
|
–
|
–
|
–
|
–
|
–
|
–
|
–
|
–
|
✓
|
✗
|
✗
|
✗
|
✗
|
| Nintendo Famicom
|
✗
|
✗
|
✗
|
✗
|
✗
|
✗
|
✗
|
✗
|
✗
|
✗
|
✓
|
✓
|
✗
|
✗
|
| Nintendo Virtual Boy
|
✗
|
✗
|
✗
|
✗
|
✗
|
✗
|
✗
|
✗
|
✗
|
✗
|
✓
|
✓
|
✗
|
✗
|
| Neo Geo AES
|
✗
|
✗
|
✗
|
✗
|
✗
|
✗
|
✗
|
✗
|
✗
|
✗
|
✗
|
✗
|
✓
|
✓
|
| Neo Geo CD
|
✗
|
✗
|
✗
|
✗
|
✗
|
✗
|
✗
|
✗
|
✗
|
✗
|
✗
|
✗
|
✓
|
✓
|
| Header colour
|
Voltage / Polarity Group
|
|
|
9 V DC, centre-negative
|
|
|
10 V DC, centre-negative
|
|
|
5 V DC, centre-positive
|
3.5 × 1.35 mm barrel
PSU Cross-Compatibility Matrix — 3.5 × 1.35 mm barrel
System ▶
PSU ▼
|
ZX Spectrum (16/48K)
|
Atari 7800
|
Atari 2600 (VCS)
|
| ZX Spectrum (16/48K)
|
✓
|
✓
|
✓
|
| Atari 7800
|
–
|
✓
|
✓
|
| Atari 2600 (VCS)
|
–
|
–
|
✓
|
| Header colour
|
Voltage / Polarity Group
|
|
|
9 V DC, centre-negative
|
4.75 × 1.7 mm barrel
PSU Cross-Compatibility Matrix — 4.75 × 1.7 mm barrel
System ▶
PSU ▼
|
Sega Game Gear
|
Atari Lynx
|
Sega 32X
|
Sega Mega Drive 2
|
Sega Nomad
|
Nintendo Game Boy (DMG-01)
|
| Sega Game Gear
|
✓
|
✗
|
✗
|
✗
|
✗
|
✗
|
| Atari Lynx
|
✗
|
✓
|
✓
|
✓
|
✓
|
✗
|
| Sega 32X
|
✗
|
–
|
✓
|
✓
|
✓
|
✗
|
| Sega Mega Drive 2
|
✗
|
–
|
✓
|
✓
|
✓
|
✗
|
| Sega Nomad
|
✗
|
–
|
✓
|
✓
|
✓
|
✗
|
| Nintendo Game Boy (DMG-01)
|
✗
|
✗
|
✗
|
✗
|
✗
|
✓
|
| Header colour
|
Voltage / Polarity Group
|
|
|
9 V DC, centre-negative (e.g., Sega Game Gear)
|
|
|
9–10 V DC, centre-positive (e.g., Lynx, MD2, Nomad, 32X)
|
|
|
6 V DC, centre-negative (e.g., Nintendo Game Boy DMG)
|
4.0 × 1.7 mm barrel
Only the Sony PlayStation (PS1) uses this connector.
No cross-compatibility with other systems.
