No good stuff. [was Re: imsai 2]

From: jpero_at_cgocable.net <(jpero_at_cgocable.net)>
Date: Thu Aug 19 14:13:03 1999

> Date: Thu, 19 Aug 1999 11:17:43 -0800
> Reply-to: classiccmp_at_u.washington.edu
> From: Mike Ford <mikeford_at_netwiz.net>
> To: "Discussion re-collecting of classic computers" <classiccmp_at_u.washington.edu>
> Subject: RE: No good stuff. [was Re: imsai 2]

 
> Are power supplies some big trouble spot lately? My impression is that they
> have a similar failure rate to anything else in the box, and that both
> premium and low cost replacements are easy to find and, well replace with.

PSUs _and_ any cooling devices spun by fan are prime troublemakers.

Problems shows up in data corruptions, complex software crashes when
system overheats whole or locally. Weak capacitors cause reboots or
PSU cut outs.

I have personally seen chips die from bad cooling for any causes if
ingored too long. CPU is chip btw.

I _did_ blow a PSU byproduct of multiple cycling 10 sec on, 2 sec
off, so on...then it died after few cycles. Analysis showed single
chopper TO-220 transistor on thin sheet of steel heatsink run by 8
pin PWM kickstarted by a 1W resistor to it, 3 bladed fan, 2 piece
axial diodes one end soldered into piece of strip for heatsink. That
psu went into bin shortly after.

PSUs based on '494 and lm339 ICs compled with decent components
especially 105C capacitors, good heatsinks, enough filter networks
and ball bearing fan in PSU case with proper sized vents did
very well. And cost difference is minimal.

Major problem that I wondered anyone haven't noticed is that
consumers DO only look at features AND cost. Oh, also consumer only
assumed that all computers is created equal on parts because decent
computer for 1100 using fewer features, good all-round cpu and OS,
one or 2 s/w OR 1000 one with weaker ill-balanced cpu, crappy parts,
highly mis and boatloads of "freebie" software and a OS, they usually
commonly picks the latter. Or don't think about it, just results.
NOT!

Resposiblity starts with rsseller educating the buyers and only sell
good ones only. Many will come to senses after going one or two
mistakes with crappy vendors and go over to good reseller. Good
wholesaler does matter much too. We were blessed with one good one.
And few good resellers.

Those stubborn bargin buyers are usually falls into 2 classes, one
who have too little knowlege and pick one by mistake, and one who
have just enough knowledge to be dangerous and have a say in
everything.

Wizard
Received on Thu Aug 19 1999 - 14:13:03 BST