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From: tjt@cuuxb.ATT.COM (~XT6561340~Tom J. Toeller~C29~M19~6092~)
Newsgroups: comp.sys.att
Subject: Re: Help! Dead 3B1 just clicks and blinks.
Summary: thermal problem?
Message-ID: <4909@cuuxb.ATT.COM>
Date: 14 Aug 90 13:45:10 GMT
References: <21187692@macs.UUCP>
Distribution: na
Organization: AT&T - Data Systems Group Lisle, IL
Lines: 21

In article <21187692@macs.UUCP>, rpb@macs.UUCP (Bob Breum) writes:
> 
> I came home the other day, and discovered my poor 3b1 going, "Click, click,
> click..." The caps lock and nums lock lights were flashing in unison, and that
> was it.  No display, no disk activity (floppy or HD), just a steady clicking
> and the smell of toasted insulation.
> 
This sounds like the power supply is switching off due to thermal overload.
To tell for sure, shut the beast off for an hour or so, and try it again.
If you get the same results right away, either the power supply is bad, or
something is overloading it (try disconnecting the hard drive power cable).

If the machine runs, check the following.
In the one fan units, it is quite easy for the fan to be slowed or completely
blocked by the wires connecting the power supply to the rear of the case.
Make sure that the fan spins. If it doesn't, pull the top off and set it
down behind the base with the screen facing up and the power recepticle hanging
over the edge of the table. This will allow you to run the unit with the top
off. Power up the unit and see if the fan runs. If it does, replace the top
making sure that the wiring doesn't interfere. If it doesn't, either the power
supply, or the fan, are defective (check the voltage going to the fan).