APOB OSCar40 DIY

Project

IR HAM aka Apob is the developer , he offer assembled and DIY Versions.

Info:

this DIY project is a clone of the OSCAR Synth, its nearly a replica.

Build Docs:

BOM:

the current BOM has few failures, a new Version is on the way.

for backup reasons, the old BOM:

Costs: the total costs was around 1250€ kit, import/VAT 22%, mouser, digikey, tme 300€, eBay 50€, keyboard icon 130€

known issues:


ID	Issue	Fix	date	fixed version
1	traces are very close to the standoffs, which can in worst case make electrical shorts affect the joystick pcb	use tape under the standoffs	12/2025
2	Quality Check cable	you have to check all cables and pinouts against the pcb silkscreen. (2 headers on my controlboard build are 180degrees rotated against the silkscreen - so I changed the wiring)
3	Quality Check soldering	check for solder bridges, check for missing or defect solder points
4	Quality Check IC orientation	its important to avoid a wrong position, wrong orientation, bended Pins,
5	Quality Check power	before you connect the PSU to the controlboard - measure -15/15V at the PSU out

The DIY Kit contains the Case, Knobs, Potentiometers, Screws.

PCBs

Controlpanel PCB

Note: remove on nearside of the ICON the screws, take the big screws at the side - you need them later !

ICON Keyboard Controller- keybed removed

Membram installed

PCB Installed

MIDI Board

first installation test

The Synthesizer is basically digital based, the heart is the Processorboard with a Z80CPU and tons of ICs.

Processor Board

rear view of Processor pcb

PSU 230V installed, 2 tested earth-ground connections installed

works great