Sac Mac after SE FDHD RAM upgrade

[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. Booted up the computer and everything seemed fine. About 2 minutes after the computer was running, pixels started to get distorted 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.

 

[havokalien]

maybe they are bigger than 1 meg. Or the memory could be bad, it does happen, all the 30 pin stuff is decades old even if its new in package.

 

[MacTech68]

Yup - error codes indicate bad RAM. Check for corroded pins on the individual chips. There could even be a cracked solder joint if they look clean.

As havokalien says - it happens.

 

[bretwashere]

The motherboard was quite dusty, including the SIMM sockets. I did clean and examine all the slots, and there was no corrosion or appearance of any broken pins. Given the sad Mac error code, is there any way to isolate which SIMM is bad? Because I might just do the 2x 256k and 2x 1mb configuration.

 

[MacTech68]

..Given the sad Mac error code, is there any way to isolate which SIMM is bad? Because I might just do the 2x 256k and 2x 1mb configuration.

Ahhh - yes, but I don't have the ability to interpret the code to a module/bank.

It might have to be a horrible trial and error process. Hopefully you only have ONE bad SIMM, else you could end up chasing your own tail - especially if the fault is intermittent.

Good Luck!

 

[bretwashere]

Ahhh - yes, but I don't have the ability to interpret the code to a module/bank.

It might have to be a horrible trial and error process. Hopefully you only have ONE bad SIMM, else you could end up chasing your own tail - especially if the fault is intermittent.

Good Luck!

I will do the "trial and error" and report back. Thank you.

And then I have to figure out how to get this miniscribe hard drive functional. It doesn't spin up at all, and flashes the code "Code E - No hall transitions during spin-up"...

 

[MacTech68]

I will do the "trial and error" and report back. Thank you.

And then I have to figure out how to get this miniscribe hard drive functional. It doesn't spin up at all, and flashes the code "Code E - No hall transitions during spin-up"...

Give the flywheel (under the circuit board) a little turn by hand, it might spin up. The "no Hall transitions" is no magnet passing by the hall sensor as the flywheel spins.

 

[bretwashere]

Give the flywheel (under the circuit board) a little turn by hand, it might spin up. The "no Hall transitions" is no magnet passing by the hall sensor as the flywheel spins.

Are there any videos on YouTube that show how to remove the circuit board? I have all the screws off, but am having a hard time disconnecting all the various wires on the circuit board.

 

[bretwashere]

Give the flywheel (under the circuit board) a little turn by hand, it might spin up. The "no Hall transitions" is no magnet passing by the hall sensor as the flywheel spins.

IT WORKED!!!

However, the "interrupter" is making quite an unusual noise and eventually gives up with an error code.

I'll start a new thread on the miniscribe and upload a video.