7300 - no boot

[Gil]

Well I upgraded my 7200 to a 7300 by upgrading the logic board, not realizing that they used different power supplies. So I got a 7300 power supply. Then I realized I needed VRAM. So I got VRAM. I also bought a PRAM battery for it too.

All I get is a chime. No video or anything. I was hoping the VRAM would solve this. I JUST realized that there is a ROM DIMM slot on the motherboard, and it looks like there are no ROM chips soldered to the board. If it doesnt have ROM, how did it give me a boot chime?

So do I need this ROM DIMM, or is there another explanation for this problem? I thought all Power Macs of this era had their ROMs soldered to the logic board.

I'm starting to think I would have been better off just buying the Sonnet Crescendo G3/7200...

 

[trag]

Which CPU card do you have plugged in.

And yes, the ROM is soldered down.

Hmmm. If you have a voltmeter, I would measure the 3.3V wires from the power supply (you can plug the probe into the back of the connector housing next to the wires). I think that without 3.3V you'll get a chime but no boot/video because one or two components of the PCI bus (the clock buffer which distributes the 33.333 MHz clock) require 3.3V in order to operate properly. I could be wrong about that. It's been such a long time since I did those experiments.

Jeff Walther

 

[Gil]

Which CPU card do you have plugged in.
And yes, the ROM is soldered down.

Hmmm. If you have a voltmeter, I would measure the 3.3V wires from the power supply (you can plug the probe into the back of the connector housing next to the wires). I think that without 3.3V you'll get a chime but no boot/video because one or two components of the PCI bus (the clock buffer which distributes the 33.333 MHz clock) require 3.3V in order to operate properly. I could be wrong about that. It's been such a long time since I did those experiments.

Jeff Walther

The processor is a Sonnet Crescendo G3, 300 MHz.

There are 2 power connectors that plug into the logic board, and I'm not too good with that kind of stuff, so you'd have to be more specific as to which of the two connectors, and which slot in the connector(s) to test.

 

[Gil]

Well I got it to boot once...

...I had a Sonnet Crescendo G3 in there that seemed to be one cause of the problem. I also had to switch between the 2 SCSI connectors on the Logic Board, from the "Fast SCSI 2" slot, to the "SCSI-1" slot. That seemed to work.

I popped in a 604e 150 MHz card that works just about every time. The Crescendo is hit or miss. :-/

 

[coius]

Let me know if you need another G3 DaughterCard. I have one for $15 + Shipping I would be willing to send you. Cheapest shipping of course.

Already has 400Mhz G3 in it, and has DIP Switches that can be used to overclock CPUs

 

[waynestewart]

You have a 9500, does the G3 card work in it? If it works well there then it's likely a problem with your RAM, motherboard or possibly power supply. If it doesn't work all the time there then you have a bad G3 card

 

[Gil]

The G3 card works *sometimes* in the 7300. I have a 604e in it right now, and you have to press the power button, wait a few second, toggle the power again, before it will show video, raster, etc. Sound to me like it could be a power supply problem, but I'm not ruling out the G3 as a possibility.

 

[jruschme]

Silly question, but did you try replacing the PRAM battery?

 

[Gil]

Silly question, but did you try replacing the PRAM battery?

Yep.

I actually took out the PCI cards and it works fine...