A while ago I got an empty Amiga 500 plus (+) case, without keyboard and mainboard. I had a spare Amiga 500 rev.8a board (and keyboard), so I decided tot upgrade that one to an Amiga 500+. In this post I show which components must be replace on the board and which changes must be done to the board.
The board before the upgrade
Components to do the upgrade
Position | Component |
U19 | DRAM 256K x 4bit 120ns |
U18 | DRAM 256K x 4bit 120ns |
U17 | DRAM 256K x 4bit 120ns |
U16 | DRAM 256K x 4bit 120ns |
U32 | 74F139 |
U9 | Oki MSM6242B (RealTimeClock) |
Y9 | Crystal 32.768Hz |
TC9 | Trim capacitor 6.8 – 45pF |
C9 | Axial 0.33uF (330nF) capacitor |
C911 | 22pF capacitor |
C913 | Tantalum radial 4,7uF / 16V capacitor (I used electrolytic capacitor) |
R911 | 470 Ohm resistor |
R913 | 470 Ohm resistor |
R914 | 10K Ohm resistor |
D911 | 1N914 / 1N4148 diode |
D912 | 1N914 / 1N4148 diode |
BT9 | CR2032 battery (with adaptor) if needed |
Memory
Components needed: U19, U18, U17, U16, U32
First remove the solder from the holes, and place sockets (low profile) or memory to the board.
CAS signals (U32)
Remove the solder from the holes, and remove the blobs from the two jumper pads.
Clock circuit
Place components: R914, C911, C9, Y9, TC9, U9
Place components: R911, R913, D911, D912, C913
Change / remove jumper blobs
JP2 setting
JP7A & JP9 setting
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Forgot to mention JP3 plobs 😉
You are right! Will add it ASAP! 🙂 Thank you!
However, excellent, accurate and very informative post! Well done!
The JP3 are the same settings ?
JP3 :
1-2 Shorted
1-2 Shorted
1-1 open
2-2 open
According to the manual
JP3 must be added to this post, forgot it, sorry for that.