Shop : PCB_Amiga 500 512KB Memory Expansion (SOJ26/20)

Amiga 500 512KB Memory Expansion (SOJ26/20)

Price :

4.99 euros

Parts : ThroughHole , SMT (SOJ 26/20)
Difficulty : 2

PCB - Amiga 500 512KB Memory Expansion (SOJ26/20)
PCB Amiga 500 512KB Memory Expansion (SOJ26/20)

This PCB is my own design, I had been looking for a PCB of a 512KB memory expansion for a long time, based on the SOJ26/20 type RAM chips.
The DIP version of the HYB514256 (and variants) is becoming scarcer and more unreliable by the day.
Since I still had a large stock of the SOJ26/20 variant, I thought it would be a good idea to design a PCB myself that uses this model of chips to build a 512KB memory expansion.
That said, it was 🙂 , doing that still took a lot of effort, but I learned a lot about how the memory expansions on the Amiga work.
The Amiga 500 512KB Memory Expansion (SOJ26/20) is a fairly general design, which has been established on the basis of various models.
The components used are partly of the Throughhole type, the Ram Chips of course not, because it was precisely the fact that these are less and less available.
The SOJ26/20 pinout has a fairly large footprint, so it can still be soldered reasonably well.

If you look for this type of IC's yourself, many 30 and 72 pin DIMMS have a handful of these chips.
can therefore be reused for such purposes, for example.

2 x Capacitor, Elco, 100uF, 25V, C902, C903 (Optional)
4 x Capacitor, 100nF , Ceramic, C1 to C4 (adapted to PCB)
1 x Resistor, 250-330 Ohm, 1/4 watt, R1 (adapted to PCB)
14 x Resistor, 68 Ohm, 1/6 watt, R2 to R15
1 x 68 Pin header, 2.54, Angled, Female (Trapdoor port connector)
1 x Led 3 mm RED
4 x HYB514256BJ (or equivalent variants)

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