A500 rebuilding project, any help?

[iconoclaST]

Well, after someone just gave me a non-working Amiga 2000, I ordered some various A500 parts from eBay. (Lo and behold, an hour after I ordered the stuff, I got the A2000 working).


The "untested beyond power up" A500 I got from ebay seems to be an A500 that was hastily thrown together from a parts bin of dead parts. After my good PAL A500 board came, I noticed the floppy drive doesn't seem to work. (Acts like normal, but reads nothing at all). Other than the power/drive lights, the keyboard doesn't seem to be acknowledged at all. Does anyone have any input on what might cause this, before I go any buy a new keyboard and floppy drive?

Also, another thing...in that event, I noticed the replacement drives and keyboards from Amigakit seem to be for the 1200/600. Will a 1200's keyboard work in an A500? Will the drive?

Or, if all else fails...how hard is it to convert an NTSC A2000 to PAL? (Most software I want to use seems to prefer PAL)

[taunusand]

The A600/1200 disk drive will work in your A500, you may have to adjust the eject button.
A1200 keyboard does not fit in A500!

You have to change your "Agnus" chip to PAL:
Chip Name -   Chip Number -   Part Number -   Used In
Agnus (512K)    8361       252125-01    A1000 (NTSC), A2000A (NTSC)
Agnus (512K)    8361 R3       
Agnus (512K)    8367       252362-01    A1000 (PAL), A2000A (PAL)
Agnus (512K)    8370       318070-01    A500 (NTSC), A2000 (NTSC)
Agnus (512K)    8371       318071-01    A500 (PAL), A2000 (PAL)
Agnus (1MB)    8372A       318069-02    A500 (PAL), A2000 (PAL/NTSC)
Agnus (1MB)    8372A       318069-029    A500 (PAL), A2000 (PAL/NTSC)

You could take the Agnus chip from your broken PAL A500 and use it in your A2000.

I hope this helps you :-)

[iconoclaST]

All I have to do is switch the Agnus?

I thought there was more to it than just switching the chip.

[TjLaZer]

If you have the 1MB Agnus, all you have to do is move a jumper (J102) to make it PAL.  If you don't have this Angus get one as you can address 1MB Chip RAM with it and that is a good thing!!!

[iconoclaST]

Both my PAL A500 motherboard and my NTSC A2000 have the 8372A Fat Agnus.

So just move a jumper... What about the clock crystal? I thought they were clocked at different speeds on different versions...

So just a jumper in the 2000? Maybe I'll put a switch on one of the back, on one of the plates for the zorro slots. Sometimes NTSC is nice to have for doing more serious stuff. (Less strain on the eyes, though 50HZ flicker is barely noticeable on my broadcast monitor as it is.

What the hell, I'll move the jumper... (I hope it's actually a jumper, and not just solder pads...)

[iconoclaST]

It was a solder bridge

But, I finally broke the connection, and it works beautifully so far. I'll be picking up a switch to install on the back of one of the slot covers to make it more easily switchable.

This was far easier to convert than a C64 (But the Atari ST is the easiest of all to switch)

Now, would switching the Kickstart ROMs really have any use? All three of my ROMS are 1.3. Don't know if they're any different between NTSC/PAL machines.

[countzero]

iconoclaST wrote:

Now, would switching the Kickstart ROMs really have any use? All three of my ROMS are 1.3. Don't know if they're any different between NTSC/PAL machines.

there're not (any differences).

[Iggy_Drougge]

iconoclaST wrote:
So just move a jumper... What about the clock crystal? I thought they were clocked at different speeds on different versions...

Yes, but it's not entirely necessary.