[rescue] Upgrading Ultra 5/10 CPUs

[Ahmed Ewing]

On Jun 21, 2006, at 9:13 AM, Rox wrote:

> On 21 Jun 2006 at 8:01, Lionel Peterson wrote:
>
>>   remove the old CPU
>>   drop in the new CPU - am I missing anything?
>> Is a special tool required to remove/install CPU?
>
> The pins are quite easily bent, and bent pins can be hard to spot, I
> recommend a very close examination of the replacement CPU before
> attempting to fit it, and any pins not dead straight need carefully
> straightening. Make sure it's square on the sockets and apply the
> pressure as evenly as possible during insertion. If the resistance
> begins to feel uneven, pull it back off and check again rather than
> just applying more force. Personally I find it best to remove the
> board from the chassis and have it flat on the bench to change the
> CPU.

I second the above wholeheartedly. It's entirely too easy to bend pins 
on the USIIi modules. IIRC, no special tools are required but there's a 
little springloaded latch that helps hold the module in place on one 
end. It makes it that much harder because you have to use one hand to 
hold back the latch while using the other to pry up the board (which 
usually ends up making the pried module end seesaw violently off the 
board, resulting in bent pins). Slow and steady wins the replacement 
race. :)

There are only two other "gotchas" that come to mind, and both are 
pretty big.

First, some U5/U10 system boards simply do not support 440MHz modules. 
IIRC, the part number can be found on a sticker on the side of the UPA 
graphics connector, and can be a pain to read without pulling the whole 
board (a non-issue if you followed Rox's advice above). If it's 
375-0009, 440MHz modules are not qualified for use and you'll need to 
upgrade your motherboard. If it's 375-0066, 375-0079, 375-0115, or 
375-3060, you're fine.

Second, there was a bad run of 440MHz modules (p/n 501-5149) you'll 
want to watch for. I vaguely remember it being datecodes 0030-0048 
(weeks 30 thru 48 of the year 2000) in the production run that were 
affected, and their being prone to premature failure that oddly could 
take days--up to a week in some cases--under full load to recreate 
consistently in a controlled test environment.  While I wouldn't say a 
bargain price alone is a telltale sign (these chips now are old enough 
to be found cheap), the datecode most certainly will be.

Hope that helps...

-A