Back to my faulty Amiga 1000

[cbmeeks]

So it's been a while since I had the Amiga 1000 on the bench.
A few years ago, I swapped the CPU, Agnus, etc. IIRC, just about every custom IC with a known working one.


The problem is that it boots to a single colored screen (RED). However, I would say it's ORANGE but all the docs say red. So maybe it's my monitor.


Not even the floppy drive will make a noise. Which makes sense. If red is a bad ROM (or something with ROM), then perhaps that's why it doesn't attempt to load anything.


Anyway, I'm running out of ideas here. I tested the voltages around the board and they look good.


My Amiga 1000 is a REV A board that has the daughter card on top. I think that's the WCS card. I pulled the WCS card out, cleaned the pins and even recapped it. Nothing. Just an orange (er, red) screen.


Keyboard LED comes on/off but after a while, just freezes.



Any ideas what to check next? I have working Amiga 500's and a working Amiga 2000 to swap parts if needed.


I also have a Kickstart disk.


Thanks for any suggestions.

[cbmeeks]

UPDATE

I managed to read the ROMS from my Amiga 1000 using my programmer.
I saved the two chips as "ODD" and "EVEN".


While the .bin files are 32KiB, the actual bytes (code) in them appears to be 3905 bytes each (before they all turn to FF's).


Now, I bought the Amiga Forever years ago so I should legally own the ROMS (both from my hardware and from purchase).


From what I understand, the ROMS in the Amiga 1000 are basically 23256's that are pin compatible with 27256's. Which is what I used in my programmer. So I hope that's right and I'm not just getting back gibberish.


I have some Atmel 28C256's which are not pin compatible (A14 and /WE are different) but I could wire a small board to correct that.


IIRC, the red error screen (actually looks orange to me) indicated a checksum error in the ROM. So perhaps one (or both) of my ROM chips are corrupt.


The Amiga Forever ROM file I found is 9KiB in size (8203 bytes, actually) and named "amiga-boot-a1000.rom".


So in theory, I should be able to somehow copy that file to a couple AT28C256's and fix the ROM checksum?


Some advise on what files to use, how to split, etc. would be appreciated. I feel like I have all of the pieces, just need to know how to assemble them. :-)


So here's hoping to restoring this Amiga 1000 I bought several years ago and never seen it work. :-)


Thanks!

[amiman99]

I think the ROMs in Amiga Forever are "encrypted" and need a KEY file to work.
I bet you can find those roms somewhere on internet.

You could use this program in WinUAE to extract the ROM from emulator.
http://aminet.net/package/util/misc/DumpA1000BootROM

[cpiac64]

i use the 27c256 or eeprom with diagrom

i can verify if your kickstart is corrupted

insert a post with checksum

[coldacid]

@amiman99: It's been several major versions of AF since they stopped requiring a key for use. What ships with 7, 8, and 9 are plain ROM images.

[cbmeeks]

Originally Posted by cpiac64

i use the 27c256 or eeprom with diagrom

i can verify if your kickstart is corrupted

insert a post with checksum

EVEN ROM: 0x00740BF8
ODD ROM: 0x007696D1




Thanks!

[amiman99]

Originally Posted by coldacid

@amiman99: It's been several major versions of AF since they stopped requiring a key for use. What ships with 7, 8, and 9 are plain ROM images.

Good to know.
I have 2012 edition installed, and I got v8 in 2019, but never installed.

[cpiac64]

i verified the checksum in 16 or 32 crc and other, but are all different

can you send me the dump?

[Nightshft]

This thread reminded me to release the new version of EpromHexxer. It now can check the Kickrom checksum. Just wanted to let you know, if it helps.
Cheers, Nightshft

[cbmeeks]

Originally Posted by cpiac64

i verified the checksum in 16 or 32 crc and other, but are all different

can you send me the dump?

Will do!


Thanks again.


FYI, I just used the checksum from MiniPro. Is there another way you're doing it?

[cbmeeks]

Originally Posted by Nightshft

This thread reminded me to release the new version of EpromHexxer. It now can check the Kickrom checksum. Just wanted to let you know, if it helps.
Cheers, Nightshft

That looks like a great tool. I will check it out.


Thanks