Amiga 500 and 1 MB on chip RAM

caiusfabricius · 26 November 2009, 11:18

Hi all,
I have an Amiga 500 ( 6A revision motherboard) with 512 kB expansion, a kickstart switcher (1.3/3.1), a 68010 CPU and a AlfaData hard disk with 4 MB of ZIP RAM.It runs very well , the only problem is that I can't run (with WHDLoad) games which requires 1 MB of chipram, like Xenon2 ,Barabarian II and others.
Someone has suggested me to do a simple hardware hack which converts 512 Kb expansion in chip RAM so I'll have 1 MB of chip in total.
Other people , instead, suggested to populate the motherboard with another 4 44C2456 memory (now I have four TMS44256-12N chips so it will be 8 in total).
In your opinion, which is the best way to operate?
The first hack is simple, I have to cut only two jumpers on motherboard but I'm a bit afraid to damage my dear Amiga 500.Does anyone has tried this hack successfully?Is it a safe hack or it may give problem in future?What are your advices?
Thanks in advance

P.S.
Fat-Agus chip labelled 318069-02 (1MB) is present on my motherboard.

Sim085 · 26 November 2009, 11:28

This guy here put 2M ChipRAM on the motherboard...
http://www.amiga.org/gallery/index.php?n=2771

In that thread he also gives an explanation of what he did. I am not sure if it also applies for A500 revision 6A motherboard however ... I think he has an A500+.

Hope it helps,
Regards,
Sim085

alexh · 26 November 2009, 11:50

Information above is useless as it is A500+

What revision motherboard do you have? Depending on the revision is is ANYTHING BUT SIMPLE.

The fact you have a 1Mbyte Agnus already gives you hope. They were only included on motherboards which were incredibly easy to mod to 1Mbyte ChipRAM using the trapdoor RAM.

zipper · 26 November 2009, 11:51

Quote:

Originally Posted by caiusfabricius

Hi all,

In your opinion, which is the best way to operate?
The first hack is simple, I have to cut only two jumpers on motherboard but I'm a bit afraid to damage my dear Amiga 500.Does anyone has tried this hack successfully?Is it a safe hack or it may give problem in future?What are your advices?
Thanks in advance

P.S.
Fat-Agus chip labelled 318069-02 (1MB) is present on my motherboard.

He has 6A like me.
Done it like thousands of users, it's safe if you have a steady hand. After having done it I installed Megachip2 so I have 2 MB Chip. Just because it can be done...

caiusfabricius · 26 November 2009, 12:09

Quote:

Originally Posted by alexh

Information above is useless as it is A500+

What revision motherboard do you have? Depending on the revision is is ANYTHING BUT SIMPLE.

The fact you have a 1Mbyte Agnus already gives you hope. They were only included on motherboards which were incredibly easy to mod to 1Mbyte ChipRAM using the trapdoor RAM.

I have a 6A revion motherboard with 8372A Fat-Agnus chip , 1MByte of chip RAM indeed.So , can I try this mod?

alexh · 26 November 2009, 12:33

I believe that is the easiest motherboard to modify to 1Mbyte.

http://aminet.net/docs/hard/a500chip.lha

caiusfabricius · 26 November 2009, 13:14

Quote:

Originally Posted by alexh

I believe that is the easiest motherboard to modify to 1Mbyte.

http://aminet.net/docs/hard/a500chip.lha

Is it worth in your opinion?

cosmicfrog · 26 November 2009, 13:28

it is defiantly worth doing

Fabie · 26 November 2009, 14:30

xenon 2 and barbarian 2 don't require 1mb chip
If that games don't work on your A500 is because your A500 fails

the only games that Im sure requires 1mb chip are Dracula and Turbotrax

Jope · 26 November 2009, 15:23

Fabie, are you talking about disk versions or WHDLoad installed versions?

The OP was talking about WHDLoad.

caiusfabricius · 26 November 2009, 17:49

Quote:

Originally Posted by Fabie

xenon 2 and barbarian 2 don't require 1mb chip
If that games don't work on your A500 is because your A500 fails

the only games that Im sure requires 1mb chip are Dracula and Turbotrax

I was talking about chip memory requirements of whdload installs for these (Xenon II and Barbarian II) two games.....look at the README of these two installs, they require 1 Myte of chip RAM.

Jope · 26 November 2009, 18:11

By the way, the only difficult to modify motherboard is the REV3.. Rev5 is quite simple, only JP7 is missing but you can just use the switch on your memory expansion or alternately bend out the exram leg of gary.. (no, don't bend any legs)

That leaves only the PAL/NTSC problem.. Use a bit of tape on the PAL/NTSC leg of the agnus or something similar. :-)

MagerValp · 26 November 2009, 19:53

Quote:

Originally Posted by caiusfabricius

The first hack is simple, I have to cut only two jumpers on motherboard but I'm a bit afraid to damage my dear Amiga 500.Does anyone has tried this hack successfully?

I did this way back when, using a hobby knife to cut one jumper, and superglued a piece of a tin soldier to short the other, as I didn't have any soldering equipment. Worked fine, and 1 MB chip is way better than 512 kB slow ram.

Jope · 26 November 2009, 22:19

Countless Amigas were modified like this in the 90s.. You're not breaking any new ground here.. Go for it!

Fabie · 27 November 2009, 00:46

Quote:

Originally Posted by caiusfabricius

I was talking about chip memory requirements of whdload installs for these (Xenon II and Barbarian II) two games.....look at the README of these two installs, they require 1 Myte of chip RAM.

I understand now....
but you can play them from floppy and you don't need to modify your A500
that games are only 1 disk long...runs very fast on the floppy drive

caiusfabricius · 27 November 2009, 00:51

Quote:

Originally Posted by caiusfabricius

I believe that is the easiest motherboard to modify to 1Mbyte.

http://aminet.net/docs/hard/a500chip.lha.

UPDATE:

I have tried this hack and it has worked fine except for some crash and "guru meditation" while I was in Workbench 3.1 transfering files from pc to Amiga with Amiga Explorer so I decided to revert back.Now it doesn't crash anymore..so this hack is not 100% safe for me at least but, maybe, I have this problems due my particular hardware configuration (see above).
I think I'll ty to add 4 TMS44c256 chips and relative capacitators, I really want 1Mbye of chip RAM in order to run some WHDLoad games, I don't see any alternative solution.

alexh · 27 November 2009, 00:54

More likely to be user error than not being 100% safe

As for adding the chips, it will offer no more compatibility. If it doesn't work with this mod it wont work with any other mod.

You must first discover what is wrong.

caiusfabricius · 27 November 2009, 01:01

Quote:

Originally Posted by alexh

More likely to be user error than not being 100% safe

As for adding the chips, it will offer no more compatibility. If it doesn't work with this mod it wont work with any other mod.

You must first discover what is wrong.

I double checked every connection and soldered points and all was fine..The system recognized the 512kB of the expansion as chip RAM but hangs during the use of Amiga Explorer..instead I have played Xenon II ( a game that requires 1Mbyte of chip RAM when istalled with WHDLoad) without any crash.

alexh · 27 November 2009, 01:03

If all your solder points are correct and you've cut the tracks correctly etc. then it must be a software conflict.

You'll have to check the AmigaExplorer tool-type and startup-sequence.

I would bet money that if you were to reverse this mod and "add 4 TMS44c256 chips and relative capacitors" you'd just be in the same situation. Amiga Explorer would hang.

caiusfabricius · 27 November 2009, 01:10

Quote:

Originally Posted by alexh

.

You'll have to check the AmigaExplorer tool-type and startup-sequence.

How can I do this?

26 November 2009, 11:18	#1
caiusfabricius Registered User Join Date: Nov 2009 Location: Italy Posts: 70	Amiga 500 and 1 MB on chip RAM Hi all, I have an Amiga 500 ( 6A revision motherboard) with 512 kB expansion, a kickstart switcher (1.3/3.1), a 68010 CPU and a AlfaData hard disk with 4 MB of ZIP RAM.It runs very well , the only problem is that I can't run (with WHDLoad) games which requires 1 MB of chipram, like Xenon2 ,Barabarian II and others. Someone has suggested me to do a simple hardware hack which converts 512 Kb expansion in chip RAM so I'll have 1 MB of chip in total. Other people , instead, suggested to populate the motherboard with another 4 44C2456 memory (now I have four TMS44256-12N chips so it will be 8 in total). In your opinion, which is the best way to operate? The first hack is simple, I have to cut only two jumpers on motherboard but I'm a bit afraid to damage my dear Amiga 500.Does anyone has tried this hack successfully?Is it a safe hack or it may give problem in future?What are your advices? Thanks in advance P.S. Fat-Agus chip labelled 318069-02 (1MB) is present on my motherboard.

26 November 2009, 18:11	#12
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,861	By the way, the only difficult to modify motherboard is the REV3.. Rev5 is quite simple, only JP7 is missing but you can just use the switch on your memory expansion or alternately bend out the exram leg of gary.. (no, don't bend any legs) That leaves only the PAL/NTSC problem.. Use a bit of tape on the PAL/NTSC leg of the agnus or something similar. :-) Last edited by Jope; 10 October 2015 at 08:51.

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26 November 2009, 11:28	#2
Sim085 Registered User Join Date: Apr 2009 Location: N/A Posts: 962	This guy here put 2M ChipRAM on the motherboard... http://www.amiga.org/gallery/index.php?n=2771 In that thread he also gives an explanation of what he did. I am not sure if it also applies for A500 revision 6A motherboard however ... I think he has an A500+. Hope it helps, Regards, Sim085

26 November 2009, 11:50	#3
alexh Thalion Webshrine Join Date: Jan 2004 Location: Oxford Posts: 14,337	Information above is useless as it is A500+ What revision motherboard do you have? Depending on the revision is is ANYTHING BUT SIMPLE. The fact you have a 1Mbyte Agnus already gives you hope. They were only included on motherboards which were incredibly easy to mod to 1Mbyte ChipRAM using the trapdoor RAM.

26 November 2009, 12:33	#6
alexh Thalion Webshrine Join Date: Jan 2004 Location: Oxford Posts: 14,337	I believe that is the easiest motherboard to modify to 1Mbyte. http://aminet.net/docs/hard/a500chip.lha

26 November 2009, 13:28	#8
cosmicfrog The 1 who ribbits Join Date: Apr 2006 Location: leek, Staffs, UK Age: 56 Posts: 3,557	it is defiantly worth doing

26 November 2009, 14:30	#9
Fabie Banned Join Date: Apr 2009 Location: France Posts: 478	xenon 2 and barbarian 2 don't require 1mb chip If that games don't work on your A500 is because your A500 fails the only games that Im sure requires 1mb chip are Dracula and Turbotrax

26 November 2009, 15:23	#10
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,861	Fabie, are you talking about disk versions or WHDLoad installed versions? The OP was talking about WHDLoad.

26 November 2009, 22:19	#14
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,861	Countless Amigas were modified like this in the 90s.. You're not breaking any new ground here.. Go for it!

27 November 2009, 00:54	#17
alexh Thalion Webshrine Join Date: Jan 2004 Location: Oxford Posts: 14,337	More likely to be user error than not being 100% safe As for adding the chips, it will offer no more compatibility. If it doesn't work with this mod it wont work with any other mod. You must first discover what is wrong.

27 November 2009, 01:03	#19
alexh Thalion Webshrine Join Date: Jan 2004 Location: Oxford Posts: 14,337	If all your solder points are correct and you've cut the tracks correctly etc. then it must be a software conflict. You'll have to check the AmigaExplorer tool-type and startup-sequence. I would bet money that if you were to reverse this mod and "add 4 TMS44c256 chips and relative capacitors" you'd just be in the same situation. Amiga Explorer would hang.

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