Hello
  Hope it's OK to top-post on this one as I hope to keep my reply fairly
short and I see no need to reply to any series of items.  While Power
Supply problems especially on a machine this old (likely not even ATX style
PS) are quite common especially if the then common mediocre-at-best quality
was/is used, your problem sound more like a heat problem.  Incidentally
overloading a circuit can cause low voltages which conversely increases
amperage as long as the breaker holds, increasing both thermal and system
instability. Incidentally, it is not impossible to acquire AT PS's for free
if other avenues fail or you determine the PS is faulty.
  There are numerous things one can and should do to maintain thermal
stability.  Starting with the CPU if it doesn't have a fan-cooled heatsink
one should be created even if all that means is robbing a 12v fan out of a
defunct PS or the like and installing an additional case fan.  If the
heatsink came with that ridiculous "thermal" tape between the hs
and cpu body I highly recommend razoring it off (it sux brand new and dries
out to worse over time even as will proper thermal grease although that
works substantially better and lasts longer) cleaning it up (even
"lapping" for best fit if he or you are industrious) and
installing new silicone grease (might cost a dollar or so and should be
good for several applications since only BB sized "pellets"
should be administered) and properly seating for re-install checking for
square fit.  They often sit "cattywhompus" offerring almost zero
contact surface due to off-centered spring clip which can be rectified by
wiggling it around a bit t
o compensate and center the downforce.  

  If he has a video card from a newer era, even of the TNT2 type, it is
helpful to utilize an old 486 fan to whisk away the considerable heat from
the GPU an video ram. In any case make sure the vidcard is  free from dust
bunnies.  Obviously and as someone else mentioned it is imortant to clean
and verify function of any other fans including the one(s) in the PS.  If
he can't/won't afford a can of compressed air it really isn't hard to
disassemble most PS's and employ an old paint brush to whisk away the
bunnies..  You might be surprised to know that those wide ribbon cables can
cause a system to overheat and especially in a seasonal way ie winter where
the PC might be near a house heating source and/oe summer if one doesn't
use AC.  If the heat source can't be separated from the PC it can be very
helpful to wrap and/or route cabling so as to minimize airflow restriction
within the case.

 There are websites devoted to "how to's" for improving thermal
conditions in PCs so either ask here or google away at your discretion,
since thermal considerations are as high or higher on the list of likely
causes as compared to gone dead components, especially given the
intermittent nature of his system's failure.

Hope this helps
Jimmy


 -------------- Original message ----------------------
From: os24u{at}wisdomtree.info
>  Worked on friend's old Pentium 166 running Warp 3 on weekend.  Box will freeze 
> each day, sometimes in half an hour, the next 3 hours.
> No discernible time frame.   Screen remains displayed at whatever activity it 
> was at.  Warm reboot unavailable.  Only solution is kill power
> switch.   Until it appears to cool down nothing displays when rebooting.  No 
> hard drive activity, no bios display, screen blank.  No peripheral
> drives function.  Cpu and hard drive function as normal once cool down period 
> has passed.
> 
>  Appears one of 3 possibilities:
> 
>   1. A chip on board is failing.    Throw away board
>    2. Power supply is fluctuating/failing.   Have multimeter to test voltage.  
> Is that sufficient?  How much voltage variance is normal?
>   3.  Computer in an old house attached to 2 power bars on 1 electric
outlet.    
> There must be 6 to 8 plugs attached to the same outlet.
>         Would the computer freeze from too many power attachments on power bars?
> 
>  Fellow is a pensioner who worked on military electronics thirty years ago and 
> informs me that the draw from all these cords from 1 outlet
> would not exceed capacity.  Am skeptical of that as I do not believe
he realizes 
> the sensitivity of computers to voltage.
> 
> Can other electrical devices attached to same outlet disturb the computer?   
> There is the computer, monitor, printer, cable modem, router,
> cordless telephone, some type of household battery charger and perhaps
another I 
> can not remember.  Further the cordless phone base
> which is an old model (maybe 20 years) sits right beside the computer.  
> 
>  I suspect interference from another device but the old fellow thinks he knows 
> all about electronics compared to myself and will not change
> anything on my speculation.  He cannot spend even $20 replacing parts at 
> present, therefore best option appears trying to remove
> interference sources first.   
> 
> Am I on the right track?
> 
>         Cal
> 
> 




[Non-text portions of this message have been removed]



 
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