PM8500 no signs of life

[Byrd]

No VRAM? I reckon that's something you'll need; the 8500 has no onboard VRAM, and it ships with two of its four slots filled (2MB, expandable to 4MB). It's probably dependant on having some VRAM, regardless of a PCI graphics card being installed.

 

[haemogoblin]

I'm pretty sure i had this machine working without the VRAM, otherwise i would have left some in.

Anyone know where i can get hold of some? I would really like to get this machine working again, it was my first ever Apple computer.

 

[Unknown_K]

Reseat the CPU

 

[haemogoblin]

The CPU has been removed and reseated so many times, it's not been given chance to settle lol

Might be getting some VRAM, so hopefully this will determine if the machine needs it to work. Tho i'm sure it booted with the PCI card without the need for it.

 

[Macdrone]

Sometimes you won't see leakage but inconsistent booting is a sure sign of bad caps. The 220 if radials that go bad in other macs never seem to leak they just die.

Good luck tho, but with as much messing as you have done the caps could almost be done. There are caps on video cards also so that could have died I guess also.

 

[Unknown_K]

Try a different CPU if you have one.

 

[Macdrone]

Wouldnt you know it there are capacitors on processor cards also. He is gonna have a heck of a time. I have a stock card if you need it, it worked last time i used the 8500 I have.

 

[haemogoblin]

Luckily i know that both video cards do work as i have tested them inside my B/W G3.

I dont believe the CPU card is faulty, otherwise the machine would not try booting from the floppy drive when i insert a disk.

 

[Macdrone]

Well the upgrade card needs a driver after boot so if the hard drive is failing then it won't full boot as no driver present.

 

[ClassicHasClass]

Upgrade cards as a rule generally don't need the extension to boot (otherwise you could never boot with extensions off). They need it to enable the caches, so they won't run anywhere near what they should, but they don't need it to merely start the computer.

That said, some of them may require NVRAM patches and resetting the CUDA would torch that, but the Sonnets shouldn't be one of them.

 

[haemogoblin]

For now i'm packing the PM8500 away, until a little parcel arrives from Canada. A fellow member has kindly come to my aid with some Vram and also a CPU card. So hopefully this will put me one step closer to understanding the problem.

BTW Does anyone else own one of these Mac video to VGA adaptors with the dip switches on it? Mine has a grey case, with 10 white dip switches on a black back panel in the center of the unit. It's not much bigger then a VGA to DVI adaptor.

Cheers

James

 

[ClassicHasClass]

They come in about a million different variants. The DIP switches are not necessarily standard between them, so if you lost the manual, you'll be guessing. Post a picture and see if someone has a similar one.

 

[waynestewart]

Try reseating the processor card. If it's even a little up in the slot then the machine won't work.

 

[haemogoblin]

Waiting now to get new processor card and some Vram to test the system further. Sadly tho my darn power switch has broke in two places. So need to find a new plastic case button or i wont be able to have the lid on the system

 

[Macdrone]

I'd try a unsharpened pencil. Any button you get will be brittle.