Am IHappy !

[Paul Maddox]

BJ

>
>This wery morning my computer (PC,pentium )went down.
>The first thing that happend was the mouse started
>jerking around the screen and after a reboot and
>2.5 minutes of usage the switched 250watt power
>supply did go doooooown the draiiiin.
>
>Now, this is the second time i have a power supply
>box in this computer that brake into a non working
>supply,i have tried to repair the first broken
>supply unit but eventually I gave up.
>I ended up replacing all the triac/thyristors
>transistors,diode's and,,,,,,,,,noooo power!
>
>Does any one have experience reparing switched
>power supplys for PC!!
>Does any one have experience of high voltage, and what not to do
>in those circuits! (Tube experts wellcome!)
>

Yes, I know how to fix them, chuck them in the bin!!.. the problem
with switchmodes is inherrant in their design, light, compact and
HIGH power, I mean... who in the right mind rectifies 250AC and then
chops it at a few hundred kHz with a varying PWM to get the voltage
that is needed!!!!
Dont play around inside them, most of it is 250v DC!!...NOTE DC!!!..

>I can only say one thing, what a hassle and stress thing this 
>Personal Computer issue are,I dont need a 250 watt's of power?
>The dude who designed PC's and their associated supplys must bee
>totally insane!
>

errr nope, the OLD IBM PC's and AT's (genuine things) had these large
PSUs because they DID need 5v at 20A, old ICs, Cmos technology, loadsa
current, most ICs now are LS, (Low power), the older ones where not..
Have you ever seen how much current a rodime R2020 20Mb full height
MFM hard drive uses when it starts, 5A on the 12V line and 3A on the
5V line.....

>Now, in a plain desperation and tierdness i went down to the
>lokal junk/old time electronic yard and digged out a
>used 125watt power supply from 1988,did some rewiring and mounted
>it in my PC, powered it upp, and now the PC seems to work.
>  

It may work, but for how long.. If you have a pentium, just remember
that power is transfered, how hot does your processor get?.. where
does all that heat come from... power from the supply rails, it may
work now, but for how long... chances are a couple of hard drives,
pentium 133, and a few cards, and you are gonna be near that 125watts!

>Now the problem is, my PC sounds like an airjet taking off,
>why all those noisy cooling proppeler's!
>I have a hard time to convince my self that a computer from
>1995 uses 20 amps at +5 volts!
>So to get this asshole to PC some silence i have filled it completely
>up with "foamrubber"rubberfoam""and you may ask,is it silent now?
>Noooooo it's not !!
>

ARGHH!!!... so youve muffled the fans to keep it quiet?.. and in so
doing restricted the air flow around the entire PSU and mother board?
stick a thermometer inside your PC now, and watch it explode...

>I have a ATARI 4Mb 1040 computer from 1986 and this computer dont use
>any sort of cooling and i have mounted a internal 220Mb HD
>and lots of internal MIDI stuff,and it goes hot.
>And this old Computer are "completely silent".
>This computer have the smallest switched
>power supply I have seen and it newer once fail over this 
>11 year period, and are still going strong for my MIDI sequensing.
>and other useful slow things.
>

because it uses low power TTL, has no extras, like hard disk, and
doesnt have 8 slots of expansion, the same with the AMIGA, but if
you look at an A2000, its has 200watt PSU, not the 65Watt of its
baby A500...

>Why can't some one build a computer for general purpose that
>have the Ataris cheap/well performing programs and hardware silence,
>the smallnes of of mac's PCB,the PC's hardware modularity,
>the stability/ruggednes and portability of Linux OS?
>

Because if you did you could set up in business and make a fortune..
You have to reach a compromise between expandiability, PC (has 8
slots on average, to compactness (macs tiny mother board) with
functionality, (atari ST).


>Or do i have to build  this my self or what!
>Since Atari, Commodore and wery soon Apple's depature!
>Or are we all doomed to this instant uppgrading 
>buissnes of Intel cpu,Bill Gates software, mister bobo's add on's!
>This wery winter I'm going to give this GENERAL PROTECTION FAULT
>crap up, I'm going over to Linux,pronto basta!
>

If you want BOMB proof, go and buy a DEC Alpha and NT4, shit hot 
ok it has a 600watt PSU and NEEDS IT!, but its damn quick, expandible
and has all the speed and power you'll ever need...

>The sum: dont use switched power supplys for your Modular syntheziser.
>

I do, I have a 5v 10A one in mine, and I wouldnt be without it!!!
with all the digital stuff Ive got planned for mine, its staying..

>BJ in smorgasboard country are some what off at the moment.
>http:/www.algonet.se/~zzynt
>

Paul Maddox




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