IBM PC Server 500

From: Russ Blakeman <rhb57_at_vol.com>
Date: Thu Feb 21 20:48:21 2002

Yeah give me some of those 62.8 ohm resistors, been searching for some of
them for a while :-)

=> -----Original Message-----
=> From: owner-classiccmp_at_classiccmp.org
=> [mailto:owner-classiccmp_at_classiccmp.org]On Behalf Of Tony Duell
=> Sent: Thursday, February 21, 2002 6:18 PM
=> To: classiccmp_at_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
=>
Received on Thu Feb 21 2002 - 20:48:21 GMT