Memory expansion for Amiga 500+ by 1MB or 512kb for Amiga 500 + RTC (real time clock)

I used 2x 512kb RAM chips V53C16258HK35 SOJ-40

Other chips should also work, but I haven't tested them.

(AS4C256K16E0-50JC , HY514260BJC-70 , IC41C16257-35K , V53C16256HK50 , V53C16258SHK50)

if someone would verify the functionality of a RAM chip, please write

You can install only RTC or just RAM chips .

For A500 it is enough to install only U1 RAM - 512kb slow RAM, for A500+ U1,U2 - 1MB chip RAM

JP1 - on/off slow RAM only for A500 (A500+ off)

JP2 - on/off RTC

You can mount the switches on either the top or bottom of the circuit board.

If you mount them on the underside so use the angled pins, you can configure them without removing it from the Amiga. But I recommend doing this only when the Amiga is switched off.

Components:

RAM:

2x IC RAM V53C16258HK35 SOJ-40 U1,U2 (for a500 only U1 is enough)

6x capacitor 100nf 0805 C1,C2,C3,C4,C5,C6

1x capacitor 10uF - 100uF electrolytic capacitor - tantal smd or through hole radial lead (for better stability) C7

1x 3 pin 2.54mm (jumper) JP1

1x Goldpin strip 2x40 female 2.54mm pitch (2x28) J1

only RTC:

3x resistor 10kΩ 0805 - R1,R2,R3

2x resistor 220Ω 0805 - R4,R5

1x diode BAT54C D1

1x capacitor 100nf 0805 C8

1x capacitor tantal 2,2uF 1206 C9

1x IC RTC62421 U3

1x CR2032 battery holder case BS-7 BT1

1x 3 pin 2.54mm (jumper) JP2

1x CR2032 Lithium cell battery 3V (non-rechargeable)

Tested A500 Rev 5, 6

A500+