Here you can buy a modern re-creation of an Amiga 500/500+ trapdoor memory board. It is very similar in function to a Commodore A501 from the 1980s, providing 512 KB / 1 MB of memory and a real-time-clock (RTC). Many original A501s have become damaged from battery acid leakage, so a modern replacement is created here.
If you purchase the 1MB variant and install it in an A500+ (the "plus" model) it will provide 1 MB of extra memory, giving a machine total of 2.0 MB CHIP RAM, the maximum possible.
This board is sold without a battery, but it takes a very common CR2032 coin cell, which you can buy at any hardware store. I have put an effort into design and component selection to ensure the RTC uses a minimal amount of power. A good quality 240mAh lithium cell will last around 6 years! A battery is not required for the memory to work.
Visit the web site for further details
Features:• A500: 512 KB
• A500+: 1.0 MB
• Real Time Clock (Kickstart compatible)
• Uses CR2032 Battery (long life)
• Small size: 38 x 89 mm
• Jumper settings without soldering
• Full 89mm height to fit trapdoor properly
• Rounded corners so you don't poke an eye out |
Jumper Settings
| JP | Name | Explanation |
| 1 (RED) | CLOCK | Removing this jumper disables the RTC (real-time-clock) on this board. Do this if you prefer to use the clock on your A500+ motherboard. A normal A500 doesn't have an RTC on the motherboard. You can disable the A500+ RTC by joining JP9 on its motherboard. |
| 2 (BLU) | ENABLE | A500: Makes the memory on the board act as SLOW RAM rather than CHIP RAM.
A500+: No effect. |
| 3 (YEL) | 1MB | A500: Keep it connected.
A500+: Enables the extra 512KB memory for A500+. Removing this jumper will run a A500+ with a total of 1.5 MB CHIP RAM instead of 2.0 MB. |
International Shipping
Now includes tracking number. Yes, it's expensive for a 50 gram item, but I'm stuck with an uncompetitive government monopoly called Australia Post :(
Local Aussie Shipping
Still shipping locally during pandemic! Items will not be registered, to avoid visiting a post office in person. Instead, you will receive it in a padded bag with two stamps and a priority label. This method works quite well and usually takes only 2-5 days.
FAQ
- Will the 1MB version work in a normal A500?
⇒ Yes, but the computer will only see 512 KB of the expansion board.
- Is a battery really required?
⇒ No, the memory works fine without a battery. Only the time and date will be forgotten.
- I have a 1 meg Agnus (A500 rev 6A) and want 1 MB CHIP RAM. How can I do that with this board?
⇒ You still have to modify JP2 on the A500 motherboard, as described on the internet. Modifying JP7A is not necessary, as the memory board has a jumper (blue) for this.
- Since the board is double-sided, will the trapdoor still close?
⇒ Yes, there's plenty of clearance.