SUMMARY: Re: PowerUp/SCSI question

From: Eugene Bogaart (
Date: Thu Feb 20 1992 - 17:11:22 CST

The following question was posted to sun-managers:

> We experience the following possible problem: A SparcStation IPC
> functions as a diskless client. A while ago we installed a left over
> sun scsi disk to this IPC, but now we changed our mind and try to
> de-install this disk. Power down, disconnect the cables, etc.
> Everything alright so far so good, but the IPC refuses to PowerUp
> without the Disk.
> What we see is the following:
> 1) After the power is turned on we see the IPC banner after a
> few seconds. (logo + three lines of text)
> 2) After this nothing happens. The Installation Guide says
> that on Power-on failure, messages are sent to serial port A.
> So we tried, but nothing to see.
> 3) Pressing L1-A has also no effect.
> If we reconnect the scsi-disk again then power-on goes well again. We
> furhter tried to use a terminater on the scsi port but no luck.
> What is the case ?? Where am I missing the point ? Or did I really
> damage my scsi interface ?

The problem was caused by a defect fuse. The IPC has two fuses near
the wall on the board. (one for ethernet and one for scsi) The SCSI
fuse is used for the voltage to the internal and possible external
terminators if nobody else does. So if it is defect the IPC will only
power-up if there is at least one external scsi device supplying the
+5VDC. I believe you can also test this by checking pin 26 of the
SCSI connector for approx +5VDC.

Thanks those who responded to my question


Name: Eugene Bogaart | Software Engineering Research Centre
Email: | Lange Viestraat 365, 3511 BK Utrecht
Phone: +31 30 32 26 40 | 424, 3500 AK Utrecht
Fax: +31 30 34 12 49 | The Netherlands

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