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- Newsgroups: comp.sys.sun.hardware
- Path: sparky!uunet!zaphod.mps.ohio-state.edu!magnus.acs.ohio-state.edu!usenet.ins.cwru.edu!neoucom.edu!wtm
- From: wtm@uhura.neoucom.edu (Bill Mayhew)
- Subject: Re: Sun 3/60 problems
- Message-ID: <1992Sep09.025840.8715@uhura.neoucom.edu>
- Organization: Northeastern Ohio Universities College of Medicine
- References: <18et21INNe2b@darkstar.UCSC.EDU>
- Date: Wed, 09 Sep 1992 02:58:40 GMT
- Lines: 44
-
- Occasionally bizarre behavior is heat related. Check to be sure
- that the fan is operating normally and that the system air passages
- aren't choked with dust. I've had several machines brought to me
- for fixing that have been virturally packed solid with dust.
- Cleaning fixed them up; on a couple I've had to replace fans with
- siezed bearings.
-
- Also, check for lose connections from the power supply to the
- backplane; occasionally, the screws loosen over time. Check the
- power supply for correct voltage. If the voltage is just below
- 4.75 volts or so, wacky things will happen, but the system will
- seem to work normally most of the time. Use care when attempting
- to adjust power supply voltage - a slip-up can fry the boards in
- your system; if you have doubts, see somebody that can attach the
- supply to a load box and adjust it outside your system. Be wary of
- the mains (120 / 220) volt conenctions to the supply input when
- probing with a meter.
-
- Pull and reseat the cards in the system. There are plenty of pins
- to become dirty, etc on a VME card connector. A couple of remove -
- insert cycles works wonders at cleaning up connections.
- Exceptionally brave users as a last ditch effort might want to try
- prying up and reseating socketed ICs. I've encountered quite a few
- bad sockets over the years, though not many on Sun gear.
-
- Check the wall socket to make sure that the voltage is nominal +/-
- 10%. Eg: 108-132 volts in the US. In the summer, heavy loads
- imposed by airconditioning in your building may make the line
- voltage to your office go way down or way up. The exact symptom
- depends on mains power transformer configuration in your building.
- Use care testing wall voltage. Refer questions to an electrician if
- necessary. Observing incandescent lights in the room for unusually
- dim or bright output may provide a clue without needing to use a
- meter yourself.
-
- Cracked circuit boards, cold solder joints, bad ICs, etc can cause
- trouble too, but that is too diffiuclt to telediagnose in a short
- article.
-
-
- --
- Bill Mayhew NEOUCOM Computer Services Department
- Rootstown, OH 44272-9995 USA phone: 216-325-2511
- wtm@uhura.neoucom.edu (140.220.1.1)
-