24 Apr
2012
24 Apr
'12
11:52 a.m.
On Mon, 23 Apr 2012, Tony Duell wrote:
I've seen it claimed by some people here that any rework degrades the
rleiability of a board. While this may well be true, this modem board
which I reworkded has been turned on each day for about 20 years, used,
and then turned off again with no problems (even though turnign it on and
off may not be good for it either).
You could claim that if it had never been reworked -- that is if it had
not needed rework -- it would run ofro even longer. THat may be so. But
quite honestly, a consumer device that runs for 20 eyars is not
unreliable. I ahev no idea what the design lifetime of the unit is, but I
would be suprised if it was that long.
So I will stick to the comment that sensible reqork does not totally
degrade reliabiiltiym and that boards that have been reworked can
certainly be reliable enopugh to use.
So, yes, its fine now. By the comments of some
peopel here, though it
shouldn't be in that reworkign the PCB should ahve reduced the
reliability. Maybe it did, if I'd got one that didn't need reworking, it
wowould go on even longer. But 20 years without problems, turned on and
used just about every day, doesn't seen unrelaible to me.
Competent "rework" fixed the other cold solder joints, etc.
Haphazard "just get it done" "rework" will only fix the one joint
that had
stopped making contact, possibly overheat adjacent pins and componenets,
add solder bridges, and in removal and reinstallation add physical
stresses to other bad joints.
So, "modern" incompetent "rework", as practiced by many companies,
could
indeed reduce reliability.
Hmmm.... Having seen some of the soldring in commercial devices I do
wonder just how it was done... A red-hot poker, perhaps....
MY experience with Sportster(S) was similar, other than that I did NOT
make the needed repairs.
Well ,as their 'tech support' was abpit as useful as a gallium teaspoon,
I had to fix it myself.
OTOH, I did not have any problems with their
Courier(S).
I never had one, so I can't comment.
We got rid of the unreliable Sportsters, and every WinModem that came
along. Deities! I hate those things!
Err, yes... Wasn't the idea to use the host comnputer CPU to do some of the
DSP worK? No thanks... I can't believe the code exists for most of my
machines...
Does anybody make a good reliable tiny portable USB
modem?
Since the origianl use of RS232 was to link a terminal to a modem, that's
the one place where there should be no problems in using it. Note I said
'should'... At least it's one place wherne I will contiune to use RS232
ports to link to modems.
-tony