SUMMARY: SPARCserver power supply problem

From: Leonard C. Whyte (lwhyte@acslink.net.au)
Date: Thu Jul 11 1996 - 07:18:23 CDT


Sun Managers,

Quite a few replies, but nothing definitive.

Several managers confirmed that they run SS10s with 384MB or greater, but
no-one appeared to have the combination with dual 60MHZ CPUs.

A Sun competitor suggested using one of their enclosures with a larger
power supply.

Let me say that the memory is ALL Sun supplied and supported.

Let me say that I have removed the internal disks to external enclosures
already, so there is no load from those devices.

Let me say that this is supposed to be a Sun approved configuration.

Let me say that I have swapped the SIMMS for an entirely different set and
the problem persists.

Let me say that I use eight 64MB SIMMS. With these ALL installed, there
are no issues of ordering/placement within the slots.

I measured the increase in mains power consumption with the eight SIMMS
removed and installed, and the eight only account for 12VA.

I DUNNO WHAT IS GOING ON. I Guess we will have to get an oscilloscope and
look at the voltage/current on each of the three DC lines at power on.

Thanks everyone for what you sent me so far.

Len Whyte

The original post:

> Folks,
>
> I have a SPARCstation 10 which I recently attempted to upgrade from 128MB
> to the full 512MB. It has two 60MHZ CPUs and an FSBE/S card installed.
>
> To my horror, I found that with the additional memory installed, the power
> supply knee'd over (folded back) on power up. I find that the power supply
> will not start reliably with four or more 64MB SIMMS installed.
>
> This machine is covered by Sun maintenance, who have replaced the
> motherboard, power supply, and both 60MHZ cpus, but still the problem
> persists. I temporarily removed the FSBE/S card and still had the problem.
>
> My question is, has anybody seen similar behaviour with an S10?
> Or, alternatively, can anyone put their hand on their heart and declare
> that they have a working example with dual 60MHz cpus and greater than four
> 64MB simms installed.
>
> This is very curious, since with three SIMMS installed, the total quiescent
> load on the power supply is only about 80VA as measured at the mains. The
> dang thing is rated for 140W, 150W peak, so I don't yet understand what is
> happening here.
>
> Any ideas or relevant experience to relate anyone?
>
> TIA,
>
> Len Whyte
> British Aerospace Australia
>



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