8500/180, reset the CUDA Chip

[PeteWeedon]

I recently bought a second-hand (I guess that's the only sort there is nowadays) 8500/180.

Got it home and connected monitor, keyboard & mouse and powered it up.

No boot chime, no video!

Opened up the machine, PRAM battery present.

Consulted troubleshooting crib-sheet. 'Reset the CUDA chip'. So I did that and the machine booted OK.

But as an engineer with hardware origins and some training in software, I'm left with the query:

What influence or stimulus originating on the outside can penetrate to the inside and disturb the CUDA chip?

Surely the seller's disconnecting his monitor, keyboard, mouse and power lead shouldn't disrupt things? The machine was transported under 'handle like eggs' conditions so I don't suspect mechanical shock.

Do I just conclude it's 'one of those things' and get on with my life? Or does someone out there have an insight into this aspect of the PowerMac?


Best regards,

Pete W.

If you can keep your head when all about you are losing theirs - you haven't seen the latest Change Note!

 

[jimbopalmer]

If I had to guess, your PRAM battery is low and just leaving it unplugged for a while was too much for it, being plugged in a while revived it, and CUDA is just a red herring.

I tried to remain child-like, all I acheived was childish.

 

[PeteWeedon]

Jimbopalmer:

Thanks for your post. I've not switched the 8500 on for a couple of days; I'll have a look and see if it's retained date and time since last time.
Then I'll report back as appropriate.


Best regards,

Pete W.

If you can keep your head when all about you are losing theirs - you haven't seen the latest Change Note!

 

[dad200uk2000]

Pete

I ha the same problem with a 9600. PRAM battrie low and left unplugged for a few weeks.

John

http://www.johnwallage.com

Two rights do not make a wrong. They make an airplane."

 

[PeteWeedon]

{b]John:[/b]

Thanks for joining in.

I'm not spurning the advice from either of you. However, the 8500, having been off for nearly a week, is still keeping good time and date. I guess the PRAM battery is probably marginal, just sitting on the brink of its discharge curve.

Unless it fails completely, it's not worth opening up the case just yet. If I have to do so for any other reason, I'll check the battery while I'm in there.

The last 1/2_AA lithium battery I bought from M*pl*n was (from memory) a bit North of £7. I'm sure they were only just over half that eighteen months or so ago?


Best regards,

Pete W.

If you can keep your head when all about you are losing theirs - you haven't seen the latest Change Note!

 

[PeteWeedon]

Oh, bother! The beastie blew up on me!

Through having too many computers on the bench at the same time and not keeping a tidy workspace, I applied mains power to the 8500 when its ADB lead to keyboard and connector wasn't plugged in. I still don't understand why that should cause the PSU to self-destruct but it didn't half make a big bang!!

Or do folks think it was just a coincidence?

Has anybody else suffered such an event? I've never seen a warning not to apply power when the ADB is disconnected.


Best regards,

Pete W.

If you can keep your head when all about you are losing theirs - you haven't seen the latest Change Note!

 

[dad200uk2000]

Peter.

I think I have a PSU that you can have.

email me at "john at johnwallage dot com"

and we'll talk.

John

http://www.johnwallage.com

Two rights do not make a wrong. They make an airplane."