"Bob" <caveguy at sbcglobal.net> wrote:
On Sat, 12 Aug 2006 22:34:21 -0400, William Donzelli
wrote:
> Really?? That was before my time (born in
'69)...I had no idea
> people whined about the advent of PCBs.
Yes, but just like the SMT issue, it was mostly
because people were
not us9ing the right tools. Early PCBs were crap - no wonder their
200W Wen soldering guns lifted the traces.
--
Will
THen there were those that that mounted vacum tubes on
PCB's and the circuit heat of the tubes
lifted traces over time.
PCB quality has gotten a lot better over the years. "Modern" PCB's with
tubes on them do just fine. But yeah, I have a lot of 50's/60's era
radios where no glue holds the trace to the board anymore, just the
solder connections at the ends!
Not to mention carbon trails and arcing around load
resistors mounted too
close and cooked the boards. PSB's were not reliable untill the
advent of transistors !
But it wasn't the fault of the tubes. In fact transistor circuits that
have any sort of power density (e.g. a regulator) put much more thermal
and resulting physical stress on the PCB than any tube ever did. I would
argue that the stresses of transistor density drove mass PCB production
into a regime of very high quality/endurance.
When talking about 50's and 60's era PCB's don't forget the nasty
tendency
for traces to develop hairline cracks for no apparent reason!
A lot of similar-to-PCB construction techniques were and still are used
with tubes. "Turret boards" and similar boards using real traces are
highly associated with the best-quality construction techniques.
Tim.