Repairing a IIsi and some LCs - messed with ROM SIMMs - Solved...

[iPhil64]

Hi all,

I have a IIsi which did work, the PSU went white smoke (failed cap).
I have now fully recaped both PSU and motherboard, and it powers up again. Well at least all power rails are good, hard disk starts to spin as well, but not chime.

In fact I think I messed up with the ROM SIMM, as I repaired multiple Macs at the same time, and I'm really not sure which one is the IIsi one now.

Is there a modern replacement for this machine ?

I also have a number of LCs (I, II and III), for which the ROM SIMM had been removed, so any idea for replacement any of these is welcome.

 

[iPhil64]

Oh boys I'm stupid....

The IISi does not need a ROM SIMM. It is soldered to the Motherboard.

Removing the ROM SIMM made the Mac boot ! Chime and cursor. Well I think the HD is dead, but at least, the Mac is functional. Another one repaired.

 

[retr01]

Hi @iPhil64!

I am glad that you were able to get your IIsi up. Sorry about the hard drive. MacSD, BlueSCSI, or BlueSCSI F4?

I thought the IIsi had a 64-pin ROM SIMM in the 64-PIN socket at J11 on the mobo. I looked, and sure enough, it does. Can you please clarify about the ROM soldered to the IIsi mobo?

I'd like to see a pic if you have a different revision of the IIsi mobo.

 

[iPhil64]

Hi @iPhil64!

I am glad that you were able to get your IIsi up. Sorry about the hard drive. MacSD, BlueSCSI, or BlueSCSI F4?

I thought the IIsi had a 64-pin ROM SIMM in the 64-PIN socket at J11 on the mobo. I looked, and sure enough, it does. Can you please clarify about the ROM soldered to the IIsi mobo?

I'd like to see a pic if you have a different revision of the IIsi mobo.

View attachment 7393​

So, yes clearly, there is a ROM socket, but on your photo you can also easily spot the 2 ROM chips on the right side of the 68040.
Now I'd be very honest, I only tested until I got a chime and cursor, not sure if it would go further.

I've taken a few days off, so can not test on my IISi right now.

 

[retr01]

So, yes clearly, there is a ROM socket, but on your photo you can also easily spot the 2 ROM chips on the right side of the 68040.

Yes, I see those two at UJ4 and UJ5 on the right of the 68030. Makes sense now.

Now I'd be very honest, I only tested until I got a chime and cursor, not sure if it would go further.

Ah, okay.

I've taken a few days off, so can not test on my IISi right now.

Okay. Enjoy your off days!

 

[iPhil64]

Yes, I see those two at UJ4 and UJ5 on the right of the 68030. Makes sense now.



Ah, okay.



Okay. Enjoy your off days!

OOOps, I even said 68040 instead of 68030... I really needed that break !

 

[johnsn]

There is a jumper you can put on to boot with the ROM SIMM.
I think it's W1 by the power connector.