Power Mac 7500

[ExplorerZ]

I'd suggest trying to borrow or buy a working 7500 PSU. Converting an ATX could lead to accidents if you're not confident.

I have a small budget, and no one to borrow from. How would I do it? Also side note, could my iici psu be used somehow?

 

[macuserman]

I have a small budget, and no one to borrow from. How would I do it? Also side note, could my iici psu be used somehow?

I’m very close to you I’m sure we could work out a way to get together for some help. I’ve everything you need to test it.

 

[fjm_48]

You may need to adjust those DIP switches. Try some of the settings for 640x480 or 800x600.

But it could be a marginal power supply. If there's no chime, and no video output, it is not starting.

If you have an ATX power supply, it could be adapted to TEST the machine with - but the pins are not directly compatible so you would need to map them to the 7500's power pins.

PowerMac 7200, 7500, 7600, 8100, G3 22 pin Molex power connector pinout signals @ PinoutGuide.com

pinoutguide.com

@Stinkerton18 put together a helpful guide here too https://docs.google.com/spreadsheets/d/1bKPddE9kDlInQ7N9fnO5qmQgvXjlHdIV0GcKRVskbZs/edit#gid=0

The spreadsheet shows the clip on the wrong side of the connector. It should be on the same side (top with respect to the PM motherboard) as the +5V trickle (yellow wire).

 

[ExplorerZ]

I just replaced the power supply to no avail. Could it be the vram?

 

[croissantking]

I just replaced the power supply to no avail. Could it be the vram?

I’ve just read through the whole thread, it’s been confirmed that VRAM won’t be the cause of the issue. I mean someone here specifically tested their 8600 board for you without VRAM and it still chimed.

I’d advise trying another CPU card now that you’ve ruled out the PSU. It’ll either be that or the motherboard, imho.

 

[ExplorerZ]

It's been a while since i read over all of this. My bad. Will try a new CPU

 

[ExplorerZ]

I finally bought a new cpu and it works! It’s a 120mhz cpu so it’s a downgrade but i still have 448mb of ram.

 

[ExplorerZ]

accidentally replied again