Re: [tlug] Dell Dimension-C Autopsy - Specifics!

["Lyle (Hiroshi) Saxon" <ronfaxon@example.com>]

Jim wrote:

> > one of them [bad cap] leaked a very dark 
> > brown goo that flowed about 8cm across the main circuit board - that's 
> > probably the detail that stopped the board from functioning.

> The presence of the goo on the board is likely _not_ what caused 
> the board to fail. The _absence_ of the goo from the inside of the 
> cap is what caused the board to fail. _Most_ of the bad caps I've 
> seen did _not_ leak. 

I know.  I meant that the trail of goo was evidence of the specific 
capacitor that probably caused the malfunction - I didn't mean to say 
that the goo on the surface of the board was the cause.  Sorry I didn't 
spell that out in more minute detail.

> > Taking a close look at the underside of the circuit board I see that the 
> > contact area for the capacitor pins is very small (having been soldered 
> > by a machine, not human hands) 

> People can solder those small pads with no difficulty. 

Okay.  But why bother when you can trash a rotten design and buy a
better one for cheap?

> > and would require a proper soldering iron 
> > at a proper temperature, with the proper very narrow tip size and - last 
> > but not least - steady and careful hands and skillful application of 
> > heat. 

> It's less sophisticated than you think. Because the caps are 
> substantial heat sinks themselves, and because the power planes 
> are even better heat sinks, one typically uses a hotter than 
> usual soldering iron but applies it very briefly. With practice, 
> the application of heat is brief. I usually unsolder both leads 
> of a bad cap simultaneously. 

Actually, I didn't mean that the heat would damage the capacitors,I
meant that the heat could damage the very small copper pads on the 
board, which can separate from the board is you overheat them for too 
long....  (Based on experience with 1980's circuit boards, so maybe it's 
not relevant any longer - but soldering skill is a *skill* - you seem to 
have it, but not everyone does!).

> > The Dell Dimension-C is the second Dell I've had to go suddenly 
> > dead on me, so I've developed a slight Dell allergy 

> Keep in mind that many many manufacturers, including 
> prestigious high-quality ones, suffered from the bad cap problem. 
> I'm not keen of Dell computers, but I wouldn't pick on Dell much 
> about this problem, because Dell had much company in this misery. 

Yeah, that's why I said "a slight allergy" as opposed to a full-blown
allergy!  There are some other things about recent Dells that I don't
like though, so the combination has me looking elsewhere.  I'm not
meaning to dump on Dell too much, but there's no particular reason why I
have to buy only Dell either!  If Fujitsu makes good computers, I might
as well buy Fujitsu...

By the way - and I asked you this before and received no answer - which 
specific "many many" "prestigious high-quality" manufactures are you 
referring to?  Specific manufactures and models would be much 
appreciated by everyone who regularly buys used equipment!  Please 
supply this specific information!  Generalizations (many many) are of no 
use whatsoever!  I'm not suggesting that you know them all, but surely 
you could supply a name or two from your personal experience in 
repairing them....

Also - out of curiosity - what is the supply of used computers like in 
your area?  Are they readily available or slightly elusive?

Lyle