Modding Rev 8 Amiga 500 board

amiga1260 · 14 July 2018, 22:47

I read on this thread: http://eab.abime.net/showthread.php?t=77705.
I only want to mod to get 1 MB Chip Mem with the 512 KB RAM from the trap door.

Do I need to mod U32 to get this working?

obitus1990 · 15 July 2018, 04:44

I just did this mod yesterday. I removed the solder bridges under U32, added U32, added the 4 RAM chips, and changed the jumpers (JP3) next to the resistor packs. The jumpers have to be changed from their vertical bridging positions to horizontal bridges instead. I then moved JP2 from pads 1-2 to 2-3, and removed the JP7 solder bridge. 1 MB chip achieved. 2mb with one of PeteAU's trapdoor expansions.

amiga1260 · 15 July 2018, 06:43

Okay, it needs to remove the blob on the U32, even you don't add 4 RAM chips?

Jope · 15 July 2018, 10:41

If you are going to use the trapdoor slot and 512k on the motherboard, just adjust JP7 and JP2. If you don't want to adjust JP7, you can use the switch on your trapdoor memory expansion.

amiga1260 · 15 July 2018, 22:05

@Jope: Thank you for information.

14 July 2018, 22:47	#1
amiga1260 Registered User Join Date: Aug 2013 Location: Gennep/The Netherlands Posts: 66	Modding Rev 8 Amiga 500 board I read on this thread: http://eab.abime.net/showthread.php?t=77705. I only want to mod to get 1 MB Chip Mem with the 512 KB RAM from the trap door. Do I need to mod U32 to get this working? Last edited by amiga1260; 15 July 2018 at 06:43.

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15 July 2018, 04:44	#2
obitus1990 Registered User Join Date: May 2016 Location: Mandeville USA Posts: 203	I just did this mod yesterday. I removed the solder bridges under U32, added U32, added the 4 RAM chips, and changed the jumpers (JP3) next to the resistor packs. The jumpers have to be changed from their vertical bridging positions to horizontal bridges instead. I then moved JP2 from pads 1-2 to 2-3, and removed the JP7 solder bridge. 1 MB chip achieved. 2mb with one of PeteAU's trapdoor expansions.

15 July 2018, 06:43	#3
amiga1260 Registered User Join Date: Aug 2013 Location: Gennep/The Netherlands Posts: 66	Okay, it needs to remove the blob on the U32, even you don't add 4 RAM chips?

15 July 2018, 10:41	#4
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,862	If you are going to use the trapdoor slot and 512k on the motherboard, just adjust JP7 and JP2. If you don't want to adjust JP7, you can use the switch on your trapdoor memory expansion.

15 July 2018, 22:05	#5
amiga1260 Registered User Join Date: Aug 2013 Location: Gennep/The Netherlands Posts: 66	@Jope: Thank you for information.

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