• Hello MLAers! We've re-enabled auto-approval for accounts. If you are still waiting on account approval, please check this thread for more information.

Quadra 650 ATX/MicroMac Conversion

IlikeTech

IlikeTech

68000
Hello, I figured I would start a topic for my custom case/ATX conversion of my Quadra 650! I got the logic board from just.in.time for $5 dollars, in untested condition. I actually found the matching connector for the power connector on Mouser! I ordered that, and I used clip leads for a first test, set up for hard power. I connected a speaker, and applied power. The board chimed, and it booted to the question mark. Yay! The board was good. Then, I connected an external scsi hard drive, which was read and it booted.

Now, I'm going to assemble the proper cable so I don't have to use clip leads. I'll post some pictures of it after it is assembled, and then I will work on the soft power circuit.

After I convert it to ATX, I will design a case and cut it on my laser cutter.

 
Cool :) I have decent knowlege of eletronics, so I don't think it should be a huge problem.

Unfortunately, the CPU was downgraded to an 68LC040.  Does anyone have a 68040 they could trade me for it?

 
Just measured the wattage of the board with a hard drive, and it is like 50 watts. I'm going switch to a PicoPSU!

EDIT: Nevermind, I can't. It draws too much power on the 5 and -12 volt rails :(

 
Last edited by a moderator:
Annnnnnnnd, success! I had the proper cable built, and I added an inverter with a 10k pull down on he PFW line, and soft power now works! Next step is to start on the case.

 
Sounds like good progress :)

Trash: When I got the board from MacMemories it was labeled as Quadra 650, and I swapped its CPU into an LC 575, putting the 68LC040 from the LC 575 back onto the board. Processor worked fine, but one game I wanted to play required the FPU (Space Cadet Pinball).

 
You can actually make an inverter board without needing the resistors. Using a 74HCT04 instead of a 74HC04 will work fine. Here's a very shitty board I whipped up a while ago. It works, but it's on my "Remake this thing prettier" some day list.

On the front half I screwed up and soldered a 3 pin connector in instead of the needed 4. 

8fc68f479c92462b0f3e310c13133d48.jpeg.8d353a5f144842619d748bcf24bc497b.jpeg


On the back side I started trying to make solder bridges instead of using wire (looks cooler) but gave up part way after fighting to make them actually connect. I need more practice with that.

4JhZH9wl.jpg.cbb218a3e1b16c07152a73df734e6407.jpg


 
You'll need a load resistor to #PS_ON as well to bring that line high when /PFW goes low, otherwise it won't be high enough to flip the inverter back around.

I never had any luck with the 74HCT04 and no load resistors. I only ever saw it in-use for an iMac. I'm guessing there are minor differences in how the power control IC changes it's logical voltages; stuff like duration, swing time, etc... Worst case scenario is you can pop open the stock PSU and see how Apple set up their load resistors, which seem to vary between models.

 
Last edited by a moderator:
I don't have the stock PSU, so that isn't an option. Also, it worked fine with just a single 10k resistor before I installed System 7.5.3. Oddly enough, the power button on the back starts up and shuts down the system fine.

Just ran a check, and the PFW line does nothing if I tell it to shut down. Let's try this again..

 
Last edited by a moderator:
Floofies said:
You'll need a load resistor to #PS_ON as well to bring that line high when /PFW goes low, otherwise it won't be high enough to flip the inverter back around.

I never had any luck with the 74HCT04 and no load resistors. I only ever saw it in-use for an iMac. I'm guessing there are minor differences in how the power control IC changes it's logical voltages; stuff like duration, swing time, etc... Worst case scenario is you can pop open the stock PSU and see how Apple set up their load resistors, which seem to vary between models.
Click to expand...
I'll have to try this on a Q650 board some day. I originally read about this working on a 9600 board and I'm using it on a Powermac 8100 board. Haven't got the right connector for a IIcx-Q650 board to hack up a PSU, been on my to-do list for a while.

 
just.in.time said:
Trash: When I got the board from MacMemories it was labeled as Quadra 650, and I swapped its CPU into an LC 575, putting the 68LC040 from the LC 575 back onto the board. Processor worked fine, but one game I wanted to play required the FPU (Space Cadet Pinball).
Click to expand...
Nothing implied, I was just curious about these particular whack-doodle boards. They can be so many mac models in so many configurations. ::)

 
I just ran Clockometer, and it said that my CPU was running at 25Mhz.  It is a 33 Mhz part. 

I started working on the laser cut case parts.  I have a laser at home so there is no cost in cutting parts.  I will do a test shot on cardboard before I cut with the expensive acrylic.  I also need to pick up a scsi2sd.

 
You must log in or register to reply here.

Similar threads

6
Quadra 605 build log
2 3
Replies
42
Views
3K
zigzagjoe
zigzagjoe
jazzius
Problems with Quadra 610 ; Dead Board and Unusual PSU
2
Replies
21
Views
2K
chiptripper
chiptripper
obsolete
Tiny Turbo Development: Like Spicy O'Clock for Power Macs (or anything with a half-can oscillator)
Replies
4
Views
390
obsolete
obsolete
E
Fair price to sell non-booting MacPortable M5126
Replies
8
Views
2K
ECJMacLearner
E
zigzagjoe
Repair of a basket case DiimoCache030
Replies
5
Views
551
Bolle
Bolle
Back
Top