Mobius 030 Accelerator Problem

[MacintoshMan1999]

I've got a Mobius 030 Accelerator card that is preventing the computer from booting When it's installed and i power on the computer the disk drive head moves and i get a screen full of garbage.

Photo:

 

[Nixontheknight]

I've got a Mobius 030 Accelerator card that is preventing the computer from booting When it's installed and i power on the computer the disk drive head moves and i get a screen full of garbage.

Photo:
View attachment 61703

check the RAM and see if the power supply is supplying the proper 5V and 12V, you can get access to both to probe through the floppy port

 

[MacintoshMan1999]

check the RAM and see if the power supply is supplying the proper 5V and 12V, you can get access to both to probe through the floppy port

The RAM is fine, the Mac boots fine without the accelerator but when I attach it the Mac still shows garbage.

 

[Nixontheknight]

The RAM is fine, the Mac boots fine without the accelerator but when I attach it the Mac still shows garbage.

then try recapping your analog board, it might not be able to handle the current of the accelerator if it hasn't been recapped

 

[Phipli]

It's the PSU that produces the voltages on these, not the analogue board.

Test the voltages on the floppy port before recapping anything.

 

[MacintoshMan1999]

It's the PSU that produces the voltages on these, not the analogue board.

Test the voltages on the floppy port before recapping anything.

Noted, Will do.

 

[MacintoshMan1999]

After a LONG time of procrastination, I've finally gotten around to ordering capacitors for my SE's power supply. While flipping around in a scan of the manual it says that ram at 100ns or faster is required for the 25MHz and I've only got 70ns. Should I get 100ns RAM?

 

[Byrd]

I don't think that's the cause of your problem, faster RAM will run at the slower specified speed (70 - 100ns).

 

[cheesestraws]

While flipping around in a scan of the manual it says that ram at 100ns or faster is required for the 25MHz and I've only got 70ns.

'ns' is 'nanoseconds' here, so lower numbers are faster - so you're already faster than 100ns. Should be fine.

 

[MacintoshMan1999]

'ns' is 'nanoseconds' here, so lower numbers are faster - so you're already faster than 100ns. Should be fine.

Whoops, bit of a dufus moment there.


I finally replaced all the caps but the bars still persist, at least the fan spins a bit faster.

Tried swapping around different ram sticks, tried it without ram, and double checked the jumper settings. I tried the troubleshooting tip in the manual (pages below) and determined its still the Mob30.

 

[MacintoshMan1999]

Could it be the processor or an IC? Tantalum Caps rarely fail so I'm discounting that.

 

[Byrd]

Show some pics - does the accelerator need it's own power source?

 

[MacintoshMan1999]

No, it does not need an individual power supply.

Pics:

 

[Byrd]

Keeping it simple, I'd reseat and clean the sockets, and switch around RAM - a lot - to see if any of the garble is different. Can the Mac boot without RAM in the SE motherboard?

 

[MacintoshMan1999]

Keeping it simple, I'd reseat and clean the sockets, and switch around RAM - a lot - to see if any of the garble is different. Can the Mac boot without RAM in the SE motherboard?

Reseat as in remove and replace the chips themselves? If so I’ve done that too all the chips except the Xilinx, don’t have a tool for that one.

Unless you mean the solder

I’ve tried swapping different RAM sticks and even tried it without ram in the accelerator, the garbage on the screen has disappeared and now only the bars remain.

The manual describes how to boot normally with the card installed by using the programmer’s switch, I’ve tried that and it works as normal.

I didn’t know that the SE could boot without RAM, I’ll try that and report back.

 

[MacintoshMan1999]

Can the Mac boot without RAM in the SE motherboard?

With the Accelerator attached?

 

[MacintoshMan1999]

No luck still, In the interim I've been attempting to install Sys 7.5 on my SE with little luck.

Any tips?