IBM PC Server 500

Yeah give me some of those 62.8 ohm resistors, been searching for some of them for a while :-) => -----Original Message----- => From: owner-classiccmp(a)classiccmp.org => [mailto:owner-classiccmp@classiccmp.org]On Behalf Of Tony Duell => Sent: Thursday, February 21, 2002 6:18 PM => To: classiccmp(a)classiccmp.org => Subject: Re: IBM PC Server 500 => => => > Boss and I talked about what he have seen from college's churning => > out students filled with knowledge but very little troubleshooting => > skills *especially* at component level and wrong type of skills to => > boot! The area students trained with were for peecee area. => => Oh, don't get me started on this (it's off-topic anyway...). I've met => graduate engineers who presumably are great with some complex equation => that I wouldn't have a clue about, but who are totally clueless when it => comes to anything practical. They're the sort of people who ask => for 362.8 => ohm resistors to use as LED current limiters, who can't estimate => component values for a simple RC filter, who can't solder anything => properly, and so on. Oh well... :-( => => > => > 1. Newish monitor sent in w/ complaint sheet stating dead. Powers up => > fine huh? Now on testing....to see if owner might be wrong. => => I guess it's got a pwoer-saving standby mode. Maybe the owner powered it => up without giving it a valid sync signal or something. => => > => > 2. Service manual for samsung 76V under warrenty flowsheet says if no => > PSU voltages present check & replace bunch of transistors and => > expensive ICs, still not fixed, replace whole board. (!!) That => => I've learnt to ignore fault-finding charts. They are rarely, if ever, => helpful. The useful bits of a service manual are the schematic (actually => I could manage with this alone if I had to), the theory-of-operation => section (if it's complete or even present), and the parts list => (if I have => to order parts it helps to have the right part numbers). => => > problem vexed me bec paper doesn't agree w/ what I find then turned => > out that poly 100nf capacitor was shorted far down the power chain => > (on CRT board) 70V rail for that intergrated tube gun amps in T220 => > 9pin package. PSU was very touchy to current level that how were no => > burn marks. I don't like shot-gun swapping chips idea. DMM and CRT => => Nor do I. I like to make measurements, look at the schematic, and change => the single faulty component. It's normally faster in the end, but of => course it requires a working brain... => => > board unplugged from mainboard gave short truth away. Did all => > tracking right on the board itself without schematic. I find using => > the schematic didn't do good for me and usually slows me down. => => No, I love schematics. I don't like working on things without a => schematic. I find that if I am probing around with no idea what I am => really looking at, then I am wasting my time. => => What I typically do is make some measurements (see the effect of user => control as well...), then sit down with the schematic and think about => what I've measured. And then possibly go back and make some more => measurements. And then think again. And then go straight to the faulty => component. => => -tony =>