BC250 - FishCase

FishCase is a desktop case for the AMD BC-250 board. The name comes from the APU’s codename, Cyan Skillfish. It was designed in Onshape and printed and tested on a Bambu Lab X2D.

Inside the case the board sits with its power connectors facing up. Mounted the other way, upside down, the stock heatsink is known to cool poorly; in this orientation that problem doesn’t occur.

Features

• Three-part body (LEFT / MIDDLE / RIGHT). Each part fits a 256 mm bed, and printed pins line the parts up.

• Two separate airflow paths. The front 120 mm fan pushes air through the board heatsink and out of the side grilles. A rear 120 mm fan cools the backplate and part of the PSU. The top vents are only for the PSU.

• Built-in power supply. A Mean Well LOP-300-12 sits in the top section under a vented cover.

• Removable front panels. Spring tabs click into detents in the body, so no screws show on the front.

• Two-color engraved front.

  • The pixel pattern, the BC-250 lettering and the fan dial ticks are engraved 1 mm deep, with a 45° chamfer.

  • One filament change at 1.0 mm gives white-on-black and black-on-white, with no AMS swaps.

• Ruthex M3 heat-set inserts for both fans and the internal mounting points.

• Optional Steam Controller stand (70°).

  • It slides onto rails on top of the right part.

  • The charging puck sits in the cradle.

  • The excess USB cable winds onto a clip (holds about 1.5 m).

Size: about 321 × 188 × 110 mm (W × H × D).

Printing

• Body: PETG, 0.2 mm layers, 15% gyroid.

  • Use 3 walls, plus a 4-wall modifier around the inserts.

  • Print LEFT and RIGHT grille-down, and MIDDLE on its side.

  • Use tree supports. With a dual-nozzle printer, a PLA or “Support for PLA/PETG” interface with Z distance 0 gives clean undersides.

  • The three body parts take about 0.9–0.95 kg of PETG.

• Front panels: PLA, face down on textured PEI, with a filament change at 1.0 mm (layer 6 at 0.2 mm).

  • Left and right panels: white, then black.

  • Middle panel: black, then white.

• Grilles: print face down and glue them in from the back.

• Stand: print the base upright and the cradle on its side. One countersunk M3 screw joins them.

Hardware

• 12× Ruthex M3 heat-set inserts (M3×5.7, Ø4.0 holes with a lead-in chamfer)

• 8× M3×30 bolts for the two 120×25 mm fans

• 4× M3 bolts for the internal mounting points in LEFT/RIGHT

• 4× M3×8 self-tapping screws for the PSU

• 2× M3×8 self-tapping screws for the power inlet

• 5× M3×6–8 countersunk self-tapping screws for the controller stand and rail plate

Assembly notes

• The case parts align on printed pins.

• The front panels snap in, and the grilles are glued.

• Fit the inserts before assembly: the 0.6 mm chamfer centers the insert before you heat it.

STEP files are included for remixing.

Tests & Temps

My board runs 40 unlocked CUs at 2000 MHz and 8 CPU cores at 3800 MHz, with a Thermal Grizzly PhaseSheet PTM phase-change pad on the APU. In FurMark at 960 mV, temperatures stay below 80 °C.

In heavy games temps are usually below 70 degrees. Fans are running below 2500rpms so it's mostly quite for me.

Cyberpunk 2077 Dogtown: 1 hour gameplay at preset: 1080p ray tracing low with GPU running at 1012mv here (it's pretty high voltage, most of the boards are handling 2000mhz under 1000mv).

AI Usage

• Stand for the Steam Controller was prepared with Claude's help, because I was too lazy to draw it by hand from scratch :P

• Originally this case was designed to use Ruthex M4 threaded inserts instead of M3, which is more popular format, so AI adopted existing holes for a new format.