Sad Mac after upgrading RAM on SE FDHD

[bretwashere]

Hello all,

The other day, I got my 4x 30 pin 1mb SIMM 80ns modules in the mail. I wanted to bring the RAM of my machine from 1 to 4 MB. I opened up the unit and replaced all four SIMMs carefully and removed the jumper. Also removed the PRAM battery and dead Miniscribe HD. Booted up the computer and everything seemed fine. About 2 minutes with the computer running, pixels started to get distorted, static noise came out of the speaker, and the machine eventually froze. Restarting the computer would give me a Sac Mac 00000004 00000040 code.

So I reopened the machine, cleaned all the SIMM slot pins with 91% isopropyl alcohol, and reinstalled the SIMM modules in different slots. Booted the machine and now I'm getting a sac Mac 0000000E 00000040 code with a black line going through the sad Mac icon.

Is there something I'm doing wrong? I bought these modules from memoryX, and they appeared to look pretty much brand new.

 

[tjjq44]

What happens if you put your 256k simms back in place?

 

[bretwashere]

I haven't attempted to do so yet. I will swap the SIMMs and report back.

 

[rsolberg]

On the SE FDHD, the jumper usually needs to be changed from the 1M position to the 2M/4M position. Leaving the jumper off sounds like the problem. If your logic board is earlier, it could have solder pads for resistors marked "256kbit" and "one row." If that's the case, neither set should have a resistor across them.

http://www.ccadams.org/se/ram.html

 

[bretwashere]

I replaced the 1mb SIMMs with the 256k SIMMs and put the jumper back to 1mb. The machine functions fine now. I will put the 1mb SIMMs back and place the jumper to the 2/4mb configuration to see if its works. Thanks for the advice.

 

[tjjq44]

If the putting the jumper in the right position doesn't help maybe one of your 1Mb simm is bad... Temporarily you can still combine two working ones with two 256kb simms for a whole 2.5meg of ram