Iisi issue

imactheknife

imactheknife

68000
Feeling lazy tonight lol.. so picked up a iisi logic with rom simm slot. It has rom on board as well. It is recapped, nothing major that i could see. It turns on, chimes and then gets death chimes. Screen comes on for a second when first turned on, then nothing, stays black.

On a side note: will an apple se/30 rom simm work in the iisi? Thanks for any info, and excuse my laziness in searching!
 
imactheknife said:
Feeling lazy tonight lol.. so picked up a iisi logic with rom simm slot. It has rom on board as well. It is recapped, nothing major that i could see. It turns on, chimes and then gets death chimes. Screen comes on for a second when first turned on, then nothing, stays black.

On a side note: will an apple se/30 rom simm work in the iisi? Thanks for any info, and excuse my laziness in searching!
Click to expand...

Might be bad ram.
SE/30 rom won’t boot a IIsi.
 
imactheknife said:
Will iivx onboard ram be the same? I assume it would be. I also have a spare classic board around and a duo 210 board.
Click to expand...

IIvx has 4MB onboard (512k per chip) so is not the same since the IIsi has 1MB.

The Classic has the same 1MB onboard (128k per chip).

FYI you can upgrade the IIsi to 4MB so you could use the IIvx as a donor if you change all the chips.

mikes-macs said:
So on the Mac IIsi there need to be a jumper on W1. This will disable the onboard ROM and allow the use of the ROM SIMM


Is your ROM SIMM a genuine Apple ROM or Custom ROM?
Click to expand...
He doesn’t have a rom simm, he said it is onboard.
 
croissantking said:
IIvx has 4MB onboard (512k per chip) so is not the same since the IIsi has 1MB.

The Classic has the same 1MB onboard (128k per chip).

FYI you can upgrade the IIsi to 4MB so you could use the IIvx as a donor if you change all the chips.


He doesn’t have a rom simm, he said it is onboard.
Click to expand...
Oh interesting. So i do have a donar iivx board. So can definitely upgrade the memory
 
imactheknife said:
Oh interesting. So i do have a donar iivx board. So can definitely upgrade the memory
Click to expand...

Yep. Not saying it’ll fix the death chimes but since you’re changing chips anyway you might as well upgrade.

Some discussion here:
tinkerdifferent.com

Upgrading IIsi onboard RAM to 4MB

The Mac IIsi motherboard is wired for a 1 MB onboard RAM array using eight 256kx4 DRAM chips or a 4 MB RAM array using eight 1Mx4 chips. After discovering this on my broken IIsi, I was able to simply replace the eight RAM chips with larger 1Mx4 RAMs (e.g. KM44C1000, M5M44400, MT4C4001) and get 4...
tinkerdifferent.com tinkerdifferent.com
 
croissantking said:
Yep. Not saying it’ll fix the death chimes but since you’re changing chips anyway you might as well upgrade.

Some discussion here:
tinkerdifferent.com

Upgrading IIsi onboard RAM to 4MB

The Mac IIsi motherboard is wired for a 1 MB onboard RAM array using eight 256kx4 DRAM chips or a 4 MB RAM array using eight 1Mx4 chips. After discovering this on my broken IIsi, I was able to simply replace the eight RAM chips with larger 1Mx4 RAMs (e.g. KM44C1000, M5M44400, MT4C4001) and get 4...
tinkerdifferent.com tinkerdifferent.com
Click to expand...
Oh ok, i remember that thread now. I actually commented on it lol.. so yeah will see.
 
imactheknife said:
Oh ok, i remember that thread now. I actually commented on it lol.. so yeah will see.
Click to expand...

I re-read the thread and Zane (the OP) was saying he doesn't recommend the mod, as it reduces performance if using onboard video. Bank A which the video uses is performance constricted so it's better to keep it to 1MB. You want all your apps to be in Bank B.
 
Durosity said:
I had exactly this issue with one of my Iisi boards.. turned out to be one of the oscillators.. I think G4?
Click to expand...
Replaced g4, no dice. Tried replacing one memory ic no dice. Guess i will have to try them all and see. Argh! Lol cant find my spare classic board. Will any of these chips work?
 

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imactheknife said:
Replaced g4, no dice. Tried replacing one memory ic no dice. Guess i will have to try them all and see. Argh! Lol cant find my spare classic board. Will any of these chips work?
Click to expand...

Did you already swap in all the RAM from your IIvx, upgrading it to 4MB?

If so, you can use the 424410 chips (because they are 4 bit chips) but not the 424100 chips (because they are 1 bit chips). Eight chips need to add up to 32 bit (the width of the data bus) hence you need to use 4 bit chips.

Otherwise, your IIsi still has 1MB onboard and neither of these chip types is suitable. You'll need to find 128k chips that are 4 bit wide.
 
Last edited:
croissantking said:
Did you already swap in all the RAM from your IIvx, upgrading it to 4MB?

If so, you can use the 424410 chips (because they are 4 bit chips) but not the 424100 chips (because they are 1 bit chips). Eight chips need to add up to 32 bit (the width of the data bus) hence you need to use 4 bit chips.

Otherwise, your IIsi still has 1MB onboard and neither of these chip types is suitable. You'll need to find 128k chips that are 4 bit wide.
Click to expand...
No havent tried that yet. I have them ready to go. I just thought i would go more original if i could pull some chips from a memory stick. I can’t find my classic parts board which ticks me off lol.. too much stuff
 
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