Fatter Agnuses into an R5 A500, worth the bother?

[RW222]

Hi folks,

I just cracked open an A500 I got a while ago and put aside, to see what I had. Turns out to be a Revision 5 with an 8370 Agnus, 16x256Kx1 chips onboard and a Supra 512K RAM/clock expansion in the trapdoor.

So, is it worth the hassle of putting an 8372A or 8375 in it? If that is, there's plenty of A500+ around that I might get for the $$$ of a fatter agnus. I would be limited to expanding chip RAM by the trapdoor wouldn't I? or is there ways and means of hacking another 512 piggybacked on to what's in there?

I'm not totally sure but I think my other A500 is a rev6 with the spare holes for another 512 onboard, and an 8372A already. (Think I've got some old boards somewhere I could steal 4x256 RAM chips from) That one is buried at the moment. Getting back "into" miggy stuff after a long break, time to dig it all out soon.

TIA for any wisdom.

[Tenacious]

Probably not.  Since there are few surplus chips around, what will you gain swapping chips from another machine.  The biggest change in usability and function would come from adding peripherals: fast ram, hard drive, cd drive, sound digitizer, video capabilities, acceleration, etc.  There are multiple ways to get there.  2 or 4 Megs of fast ram alone is a more profound improvement over new ECS replacements and the theoretical max of 2 megs of chip ram.


Having said that, I admit that I converted the trap door ram of all 4 of my a500s to chip ram.  One A500, I put 2 megs of chip on the motherboard and only use the rtc in the trap door.  Added ECS for productivity video mode - and I've never found much use for that mode. Grin.

[Damion]

RW222 wrote:
Hi folks,

I just cracked open an A500 I got a while ago and put aside, to see what I had. Turns out to be a Revision 5 with an 8370 Agnus, 16x256Kx1 chips onboard and a Supra 512K RAM/clock expansion in the trapdoor.

So, is it worth the hassle of putting an 8372A or 8375 in it? If that is, there's plenty of A500+ around that I might get for the $$$ of a fatter agnus. I would be limited to expanding chip RAM by the trapdoor wouldn't I? or is there ways and means of hacking another 512 piggybacked on to what's in there?

I'm not totally sure but I think my other A500 is a rev6 with the spare holes for another 512 onboard, and an 8372A already. (Think I've got some old boards somewhere I could steal 4x256 RAM chips from) That one is buried at the moment. Getting back "into" miggy stuff after a long break, time to dig it all out soon.

TIA for any wisdom.

It may be worth it, because (IIRC) 8370 Agnus can only address 512k RAM, and you're limited to NTSC only. There are quite a few games that require 1 meg chipram and/or are PAL.

You *could* rock the 6A board and solder on the extra memory (plus jumper mods I think).... but IMHO it's easier to add the other 512k via the trapdoor, and then utilize an ADRAM or something off the expansion slot for other memory. (Unless you're just after the pure fun of trying it, in which case, why not? :-))

I see these babies on ebay all the time, and if they sell, it's usually for peanuts. They work great for a simple A500 games rig.

[Zac67]

If you can get a proper Agnus, the board modifications are no problem and probably worth it. It'll change your trapdoor expansion's RAM to real chip mem. Expanding beyond 1 MB total can be tricky and/or expensive.

However, I wouldn't spend too much on an A500 since an A1200 offers so much more. (No offense ment.)

[alexh]

Unless you have a lot of additional A500 hardware, sell / ditch it and get an A1200 + internal Hard drive.