Fully external, no case opening
Plug the brick to the ST and the USB-C PD charger to the brick. Nothing goes inside the computer. No soldering, no internal modifications.
ATARI 520ST
Fully assembled external USB-C PD PSU brick. Drop-in replacement for the original Atari 520ST short power brick. No case opening, no soldering, no internal modifications.
What you get ↗
Replace the original Atari 520ST short power brick
The SidecarTridge External USB-C PD PSU is a complete, fully assembled replacement for the original external brick that shipped with the early Atari 520ST short. A modern USB-C Power Delivery multi-rail board lives inside a custom resin enclosure with rubber feet, terminated through a professionally manufactured cable harness with a 7-pin DIN connector. Plug a USB-C PD charger into one end, plug the DIN into the back of your ST, and you get clean, regulated +5V, +12V and -12V rails. Sized for the Atari ST family and any SidecarTridge add-ons hanging off it. Safer than running a 40-year-old brick with dried-out capacitors.
From €40 plus taxes. Ships from Spain. Atari 520ST short only.
Key features
USB-C PD multi-rail output
Independently regulated +5V, +12V and -12V rails sized for early external-PSU Atari ST models and any expansion hanging off them.
Purpose-built for Atari rails
Built around the proven SidecarTridge USB-C PD Multi-Rail board. No generic USB-C trigger boards or DIY PD adapters.
Integrated +5V USB-A output
A regulated +5V USB-A port on the enclosure powers ACSI2STM, SatanDisk, Gotek and other accessories that can't be powered from the ST internal lines.
Pre-assembled 1 m harness
Professionally manufactured cable harness, 1 meter long, JST VH 3.96 mm 6-pin on the PSU side, 7-pin DIN on the Atari side. Ready to plug.
Resin enclosure with rubber feet
Custom white resin enclosure, precision manufactured, pre-installed rubber feet to keep the brick from sliding off the desk.
What you get in the kit
SidecarTridge External USB-C PD PSU
from €40 plus taxes
- White resin enclosure, precision manufactured, with pre-installed rubber feet
- SidecarTridge USB-C PD Multi-Rail board, pre-installed and fully wired
- 1 m cable harness: JST VH 3.96 mm 6-pin on the PSU side, 7-pin DIN on the Atari side
- 4x M2 8 mm screws for the enclosure
Ships fully assembled. You provide the USB-C PD charger and the USB-C cable.
Installation
- Get a USB-C PD charger that meets the requirements below.
- Unplug the old Atari power brick from the wall and from the ST.
- Plug the new PSU into the ST via the 7-pin DIN connector.
- Plug the USB-C PD charger into the PSU and into the wall.
- Power on.
No case opening. No soldering. No internal modifications.
Compatibility
| Atari model | Status |
|---|---|
| Atari 520ST short (motherboard C070115) | Supported |
| Atari 520ST short (motherboard C070243) | Supported |
| Atari 1040 STF, STFM, STE, Mega ST | Not supported (use the Internal USB-C PD PSU) |
| Atari Mega STE, TT, Falcon | Not supported |
If you are not sure which board your 520ST has, check the silkscreen of the motherboard before ordering.
USB-C PD charger requirements
You bring your own charger. Pick a unit that meets all of the following:
- Power: 45 W minimum
- Standard: USB-C PD 3.0 compliant. PD 3.1 chargers with Extended Power Range (EPR) may not negotiate correctly even when they advertise PD 3.0 fallback.
- Profiles: must expose both 15 V and 20 V PD profiles. Chargers limited to QC-only or PPS-only are not supported.
- Cable: USB-C cable rated for 45 W or higher (most USB-C PD cables qualify).
A vetted list of chargers known to work lives in the USB-C PD PSU documentation.
Specs
- Weight: 250 g (assembled)
- Enclosure: white resin with pre-installed rubber feet
- DC output: +5V, +12V, -12V (Atari ST rails)
- Auxiliary output: regulated +5V USB-A port on the enclosure
- Input: USB-C PD 3.0, 45 W minimum, 15 V and 20 V profiles
- Atari connector: 7-pin DIN, pre-terminated on the supplied 1 m harness
Frequently asked questions
Hardware & compatibility
Which Atari models are supported?
The 520ST short (motherboard revisions C070115 and C070243), which shipped with an external power brick. For the 1040 STF, STFM, STE and Mega ST with an internal PSU bay, the right product is the Internal USB-C PD PSU. Mega STE, TT and Falcon are not supported.
What does the +5V USB-A output do?
The enclosure exposes a regulated +5V USB-A port that can power external storage like ACSI2STM, SatanDisk or Gotek without loading the ST internal rails. Just keep an eye on total current so you do not exceed the PSU output.
Can the PSU harm my computer?
The PSU is sized for the Atari ST family rails and is safer than a 40-year-old brick running on dried-out capacitors. The risk is in the charger and cable you bring: stick to USB-C PD 3.0 from a reputable brand and a certified USB-C cable.
Installation
Do I need to open my Atari to install this?
No. This is a complete external replacement for the original brick. Unplug the old brick, plug this in, you are done.
Do I need any tools?
No. The cable harness is pre-terminated, the enclosure is pre-assembled. Just a USB-C PD charger and a USB-C cable.
Power & adapter
What USB-C PD power adapter do I need?
A 45 W USB-C PD 3.0 charger with both 15 V and 20 V profiles, plus a certified USB-C cable. Most modern laptop and tablet chargers from reputable brands meet these requirements. A vetted list of tested chargers lives in the docs.
Can you recommend a specific charger?
As a supporter of European brands, the Raspberry Pi 45 W USB-C Power Supply is a verified, affordable option that meets every requirement. Any laptop-class USB-C PD charger from a reputable brand that supports the 15 V and 20 V profiles and delivers at least 45 W should also work. Check the list of tested USB-C PD adapters for specific models verified with our PSU.
Does it run on PD 3.1 chargers?
Some PD 3.1 chargers with Extended Power Range (EPR) do not negotiate correctly with this board even when they advertise PD 3.0 fallback. Stick to PD 3.0 chargers from the tested list when in doubt.
Community & policy
Is this product for me?
Yes, if you own an Atari 520ST short with an external brick that is tired, drifting or already dead, you want a clean modern replacement powered by a USB-C PD charger you already have around, and you appreciate not opening the computer. It is a homebrew product built for hobbyists, not a sealed appliance.
Why can’t I access the store even though you ship to my country?
Access to our products and community spaces requires basic respect. We have zero tolerance for harassment, personal attacks, abusive behaviour or defamatory content toward our team or community. The principle is simple: don’t be abusive. If that principle is violated, access is revoked. We build for people who enjoy experimenting, not for people creating hostility.
Certifications & Compliance
This product is built around the SidecarTridge USB-C PD Multi-Rail power board, which has been assessed for European (CE) and UK (UKCA) conformity. Official Declarations of Conformity and EMC Assessment reports (USBC-PD-PSU REV1.1.0):
