Hello Declan, W.r.t. 'elco': Apologies, a Dutch abbreviation that slipped through the Dutch -> English converter: In dutch an electrolytic capacitor is called ELectrolytische COndensator, commonly abbreviated to ELCO. It is such common slang that i never realized that it's not used in the English-speaking fraction of the world ;-)
Sorry about the confusion i caused, Peter > -----Original Message----- > From: Declan Moriarty [mailto:[EMAIL PROTECTED]] > Sent: donderdag 19 september 2002 13:09 > To: Multiple recipients of list CHIPDIR-L > Subject: Re: Best approach to a dead atx pc? > > > Was it Faasse, P.R. who wrote on Thursday 19 September 2002 10:48: > > Hello Declan, > > > > You mention an ATX supply, so i'll assume that the whole > rest of the system > > is not too antique... > > > > It definitely looks like you have a spare ATX connector :-) > > Yep, I'll go with that. > > >You could cut > > it loose from the ATX supply, look up the specs for the > voltages -> pins of > > the ATX supply output and then go to work on the mainboard. > Remove all that > > you can from the PC (video card -if there-, other I/O > boards, CPU, memory, > > disks, whatever else is connected to the supply :-) and > then try to supply > > each of the board's voltages with the lab-supply you > mentioned and the ATX > > connector. > > I gather you share my hesitation just to plug in another psu Not 100%, if you have one you can afford to lose, the results might not be that bad. But i do agree: a 5.0V supply that is willing to blast some 20 Amps into a non-too-reliable circuit like your mainboard could well end up in another fireworks display. > > > > You *might* burn something on the mainboard that way, but > the chances of > > that i would not guess to be that high. > > I'll take my chances here :). I kind of know what I'm doing > there. Divide and > conquer. > > Besides, you just removed all > > 'salvageables' from the system :-) If any of the 5.0V, or > 3.3V voltages are > > shorted: despair. These voltages are used all over the > board, and you'll > > have a ball finding out which of the chips has burned, not > to speak of any > > attempts to replace them (have you ever replaced ball-grid > chips with > > d.i.y. means? I tried and fried the result... you can't > really see *what* > > you have just interconnected). The + or - 12 Volts are > usually only used > > for the RS232 buffer chips and perhaps a few other places > (CPU 'internal' > > 2.0 .. 3.5 Volts supply), so if they short there is hope yet. > > > > NB: a ATX supply needs to be 'switched on' from a signal on > the board. You > > might well find that the 5.0 V will draw ~0.0 mA because > the 'switch' > > signal is not on. There ususally is a jumper connection of > the board that > > must be shorted for a moment to switch 'on' the supply. > > I'd like to find that..... It's usually the jumper that connects to the 'on/off' switch on the ATX board. Short pulse on the button for on/off (= sleep), long press to 'really' switch off (more or less suspend..) > > > > > Another note: when the 12V and 5V are ok, you should have a > look at the CPU > > voltage(s): they are usually made from the 5 V and/or 12 V, > and these > > modern s/m 5.0 -> 2.0 .. 3.5 Volts converters are ticklish... Not so > > difficult to analyse (AD1148 controller chip + a few > mosfets), and usually > > quite possible to repair. > > > > If you get through that, then you can start trying the I/O, > disk etc... > > Funny, I thought the peripherals could be checked easier and > would have gone > there first, trying to get a feel for the damage. If the > disks are blown > away, I won't give much fot the m/bs chances > Agreed, but the only way to check them more or less reliably would be to connect them to a -known-good- system. My reservation about that is that, when the I/O is burned badly, you just might end up with *two* damaged computers and/or supplies... > > > > NB: Thing just might be less grim than they look: If one of > the secondary > > elco's blew when you switched the thing on, then that may > well be because > > it got the heat when power was drawn from the supply. In my > experience > > burned elco's are the #2 reason for defect s/m power > supplies. Elco's seem > > to be designed for 50 Hz recification, and the >40 kHz may > well make them > > develop 'series resistance'. When the power drawn from the > supply goes up, > > then the dissipation in this 'series resistance' goes up, > and your nice > > explosion could well be the result. One more reason to mistrust ATX > > supplies is that they keep the supply 'dormant' all the > time instead of > > really taking the power off. The dormant state means that > the s/m part of > > the supply keeps working, and banging on the elco's. I have > developed the > > parctise of putting 1.0 or 2.2 uF non-electrolytic > capacitors in parallel > > to the output elco's of any s/m supply that i am fond of. > The non-elco > > capacitors 'eat' the high-frequency currents, so that the > elco's can do the > > low-frequency filtering without getting all of these high > peak currents.. > > ELCO? Are we talking about output capacitors and ESR? I > didn't get this. elco = Electrolytic capacitor: the output/etc capacitors of the supply.. VVVVVVVVVVVVVVVVVVVVVVVVVVVV ( Picking over the entrails of the psu, I find a capacitor case ) ( (100uF 10V) ) ^^^^^^^^^ those kind of buggers are called elco's in dutch > > > > W.r.t. your PC: another matter is how much trust you will > have in the > > components of a 'refurbished' PC should you get the thing > on the road > > again... Some of the parts of the PC might well have gotten > a 'kick' that > > brings them on the edge of breakdown, so they die on a > quiet moment later > > on. > > That's fine - It's the lousiest m/b ever - SiS 5513/5591 & > with onboard SiS > 6326. Lovely bios - shame about the rest of it. I'll gladly > sling it and buy > new. I don't care if it dies - it's function in life was to > keep my kids off > MY pc. The only 'important' things on that were mp3s of > 'music' lacking > finesse, and games Good luck then :-) > > > > > hope it helps, > > > > Peter > > > > > -----Original Message----- > > > From: Declan Moriarty [mailto:[EMAIL PROTECTED]] > > > Sent: woensdag 18 september 2002 20:19 > > > To: Multiple recipients of list CHIPDIR-L > > > Subject: Best approach to a dead atx pc? > > > > > > > > > I powered up an atx pc here, which ran for three seconds > > > before there was a > > > LARGE flashand everything went quiet. > > > > > > Picking over the entrails of the psu, I find a capacitor case > > > (100uF 10V) > > > empty and loose. It apparently lived in the output area of > > > the power supply > > > on the low volts side. The fuse is vaporised. It looks grim - > > > like some HV > > > got accross. Capacitors don't normally do that! > > > > > > What's the best route now? The psu is toast - I'm wondering > > > about the m/b > > > and hesitant to slap another psu on it, as I have enough > > > toast. But it might > > > be OK, or some of it might. > > > > > > I have a lab supply here (2 x 30V 2.5A @ 1x5V 2.5A or 1-15V > > > 1A), a Signature > > > analyser even, but I'd like to hear opinions. How do you > > > trick an atx board > > > into life anyhow? > > > > > > -- > > > Regards, > > > > > > > > > Declan Moriarty > > > > > > > > > > > > > > > Applied Researches - Ireland's Foremost Electronic Hardware Genius > > > > > > A Slightly Serious(TM) Company > > > > > > Experience is like a comb, > > > that Life gives you - AFTER all your hair has fallen out! > > > -- > > > Author: Declan Moriarty > > > INET: [EMAIL PROTECTED] > > > > > > Fat City Network Services -- 858-538-5051 http://www.fatcity.com > > San Diego, California -- Mailing list and web hosting services > > --------------------------------------------------------------------- > > To REMOVE yourself from this mailing list, send an E-Mail message > > to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in > > the message BODY, include a line containing: UNSUB CHIPDIR-L > > (or the name of mailing list you want to be removed from). You may > > also send the HELP command for other information (like subscribing). > > -- > Author: Faasse, P.R. > INET: [EMAIL PROTECTED] > > Fat City Network Services -- 858-538-5051 http://www.fatcity.com > San Diego, California -- Mailing list and web hosting services > --------------------------------------------------------------------- > To REMOVE yourself from this mailing list, send an E-Mail message > to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in > the message BODY, include a line containing: UNSUB CHIPDIR-L > (or the name of mailing list you want to be removed from). You may > also send the HELP command for other information (like subscribing). -- Regards, Declan Moriarty Applied Researches - Ireland's Foremost Electronic Hardware Genius A Slightly Serious(TM) Company Experience is like a comb, that Life gives you - AFTER all your hair has fallen out! -- Author: Declan Moriarty INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB CHIPDIR-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Author: Faasse, P.R. INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB CHIPDIR-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
