🚀 go-pugleaf

In <4mov87$rm0@wraith.cs.uow.edu.au> david@wraith.cs.uow.edu.au (David E A Wilson) writes:

>We have a Sun 4/470 that failed and now gives the following message during
>the power up self test:

>Cache Data RAM Write-Write-Read-Read Test.
> error: PA=0x90014adc, VA=0x072c5a90, Exp=0xa568d3a5, Obs=0xa569d3a5. (looping)

>I guess this means that one of the cache data RAM chips has failed - but which
>one. There are 16 labeled U0800-0807 and U0900-0907 and they are soldered.
>Were they socketed I would swap them to see when the fault moved but with
>them soldered I want to know exactly which chip is bad before trying to
>replace it.

I haven't seen this sort of error before from a VME CPU board, but I think
the value after 'Exp' means what was expected to be seen, and the value
after 'Obs' is what was actually observed. Based on these assumptions, the
figures reported indicate that the error is confined to the 17th bit at
the location being accessed. 

I'm not sure of the meaning of the 'PA' and 'VA' figures unless they are
the 'Physical Address' and 'Virtual Address' respectively of the location
that gives the error. Does anyone know how these inter-relate to enable
the defective cache RAM device to be identified? 

I have a 3/470 CPU board here which has all of the cache chips soldered
in. I think it's done for reliability, but of course it makes it hard to
diagnose faults by simple chip-swapping. The 4/280 which is currently my
main home server machine also has the cache RAM soldered to the CPU board. 

>Thanks in advance for any assistance you can offer.

>P.S. any idea how much 16Kx4 bit cache chips are? QS8882-15P or CY7C162-15PC.

The CY7C162 is a Cycle Computer product. They probably do have a
distributor of their IC devices here in Australia, but otherwise they are
on the net and can be contacted via their web page, which is
'http://www.cyclecc.com'. 

Regards,

Craig.
-- 
        Craig Dewick - craig@zeta.org.au - http://www.zeta.org.au/~craig  
                          Located in Sydney, Australia.
          Sun Ripened Kernels - http://www.zeta.org.au/~craig/srk.html
                Surplus and pre-loved Sun Microsystems equipment.