Yamaha NP 55xxx
This page was last modified 16:16, 30 May 2021 by Mars2000you. Based on work by Gdx and Rderooy.


The Yamaha NP 55xxx are a series of large (245x60x100mm) and heavy (1.1kg) external power supplies (PSU), that were supplied with the majority of Yamaha CX5M series of MSX computers, with the exception of the CX5MC and CX5MU regional variations which have an internal 120V power supply. They have the same output voltages, but the input voltages and wall plugs vary according to the intended region.

Product Region Input voltage Wall plug Supplied with
Yamaha NP 55130 Scandinavia AC 220V ~ 50Hz 30W CX5MS
Yamaha NP 55140 UK AC 240V ~ 50Hz 30W BS 1363 CX5ME
Yamaha NP 55150 AU, NZ AC 240V ~ 50Hz 30W AS/NZS 3112 CX5MA
Yamaha NP 55160 Arabic has a voltage selector Sakhr AX-100
Yamaha NP 55170 FR AC 220V ~ 50Hz 30W CX5MF, YIS-503F and YIS-503FB
Yamaha NP 55180 DE AC 220V ~ 50Hz 30W Schuko (CEE 7/4) CX5MG

If the power supply is missing, it can be difficult to source a replacement, as it not only uses an unusual connector, but it also supplies multiple voltages.


Atari ST video connector
Yamaha NP 55150
Yamaha NP 55160
Yamaha NP 55160 back
Yamaha NP 55180 back


The connector is an 13 pin DIN connector probably same as video connector of the Atari ST.

  • Input: various, see table above
  • Output:
    • DC5V ⎓ 1.9A
    • DC+12V ⎓ 0.5A
    • DC -12V ⎓ 0.16A
Yamaha NP 55xxx Connector pinout