2 Jun
2007
2 Jun
'07
3:39 p.m.
No - I'm saying that surely a 1000 transistor
board with circuits that repeat
is no more or less difficult than a 1000 transistor board where nothing
repeats; the level of effort required is largely the same as it's tracing the
interconnects which takes the bulk of the time, and that's got to be done
fully for both boards to guarantee an accurate schematic. (All of which
probably means that the number of PCB layers is irrelevant too - the critical
thing is the number of solder points)
I'm not disputing that doing a 1000 transistor board is easier than something
with BGAs on it... :-)
I had a situation very recently with a Dell W2600 LCD
(26" widescreen). At first, thought was power issue yet I can feel
relay click so there was some activity in the mainboard that turns on
just the main supply but not the other 3 items turning on (via
another control line) for PFC, LCD supply and audio supply.)
Backtracked to the mainboard and determined that transistor is a PNP
and is not pulling up a signal for that 3 items. What I did was to
hopefully see if the rest of other items on mainboard is live by
grounding that base of PNP transistor with a resistor. All the power
supplies came up but nothing on LCD even lamp didn't light.
Oh well, that will be scrapped anyway since owner doesn't want to
spend much. The mainboard is one honking big multiple quad & BGA
ICs.
Cheers, Wizard