Most of this civilian computer stuff isn't really geared towards harsh life. Even garden tools aren't. I had a shovel with plastic handle where the top plastic layer had softened, discolored and became soft. I didn't notice until the stuff was stuck to my paws.
I am surprised this BFC ever made it through a design review. Or maybe the ECO was just rubber-stamped and robo-signed :-)
One of the reasons I don't do fixed bid work :-)
-- Regards, Joerg http://www.analogconsultants.com/
mythbuster tried it, think they saw a difference of 10'F between black and white car
-Lasse
Really. So then you've got nothing to worry about.
Solar contribution to thermals ia roughly a kilowatt per square meter in the direct overhead case.
RL
This message has been purged of all expletives or any sentences containing them.
I beg to differ. Although most of the stuff I work with is rated from
0 to 70C, reality has a way of exceeding the specifications. For example, realistic automotive temperature spec is -40C to about 100C (or more). Engine compartments get very hot.Recently, we attached a disposable temperature data logger into an aluminum radio case and let it run for most of salmon season. It went well over 100C for extended periods when the sun was shining directly on the case. The vessel owner also complained that his iPod blew up when left sitting on the top of the same radio. He blamed RF from the radio, but it was more likely fried by excessive heating. Incidentally, when I did an autopsy on the radio, most of the screws had rattled loose. I should have also attached a vibration and accelerometer data logger.
Clever design. Wrap the handle with duct tape. Most such things are designed for a specific useful life. I suspect (but can't prove) that research has been performed into reducing the life of plastics under the guise of having the plastic break down in the landfill. While it seems a worthy area of research, I suspect that such plastics would also deteriorate before they reach the landfill. A modest example is the simulated rubber coating used to simulate a real rubber handle on some hand held tools (e.g. Sears IR thermometer) and your shovel. It is designed to turn to sticky mush after about 3-4 years, which is just about right to insure that none are returned under warranty. I found that ordinary rubbing alcohol does a tolerable job of removing the sticky goo without affecting the underlying plastic (usually ABS). I've seen similar controlled failure designs in the selection of electrolytic capacitor voltage ratings and power transistor thermal cycle calculations. It's fairly easy to predict the onset of such component failures.
What design review? I don't want to go into excessive detail, but basically the design was purchased from a consultant in India and rushed into manufacture without adequate testing. First to market and cost were the overriding concerns. There were plenty of other things wrong with it. I was sweating blood because the independent certification lab was complaining that they couldn't make it pass Part
15 Class A without major modifications. My job was to make these major modifications, but not change anything, since the product was being manufactured and stockpiled pending approval. Other engineers working on the device used this as an opportunity to fix a few things, which required my approval since it affected the type certification. That made me effectively in charge of coordinating everything and guaranteed that I would be blamed if anything went wrong. The BFC fix was added under my watch. Things went amazingly smoothly. The certification lab was able to generate the required FCC paperwork. Changes were made that didn't involve a PCB revision. There was some grumbling over the necessary rework. No real problems until the RJ45 arcing problem appeared.That's one mistake I haven't made since. It's an open invitation for abuse as I learned the hard way. However, I created my own problem. I could have said "it's not my job" and let someone else handle it. I was thinking that I could play hero and impress management sufficiently to get more work from the company. That didn't happen.
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
Sure, but there is also re-radiation and reflection. Except maybe for a Hell Angels Harley or a low-rider rap mobile, vehicles are normally not painted a dull "primer black". It's more metallic-anthracite plus a shiny clear coat on top.
But I didn't use any :-)
-- Regards, Joerg http://www.analogconsultants.com/
Oh, yeah - don't get fahrenheit and centigrade mixed up. This tends to happen in anecdotal conversation with Americans.
RL
And some automotive engineers should have their head examined. On one car a module that controlled some stuff in the engine was literally mounted on top of the engine. Sometiems on hot days the van would refuse to start ...
The starter on my wife's Corolla just died. Where did they put it? Between intake manifold and engine! Unreachable, and gets hot there.
I was taught very early on that eveything on a boat must be nicely strapped in and will corrode away in no time. And that stainless doesn't really mean stainless.
This one is soft goo stuff all through :-(
Ah, a design from Outsourcia :-)
If someone insists on fixed but I either insist on cast-in-concrete specs plus change-order procedure, or decline. Since neither is desired by clients it's all by the hour for me.
-- Regards, Joerg http://www.analogconsultants.com/
m
I've fixed the starter on few corollas and getting that thing unbolted down behind the engine can drive you nuts
the fix is simple, there's even a cheap kit for it, the thing that break is the "switch" inside, basically two pieces of copper angle that gets shorted via a copper disc when the started gear is engaged one of them gets eaten away, buy the kit or bend a piece of copper and it will run for another 10 years
-Lasse
With my arm size I don't see the slightest chance to reach in there unless I take the whole intake manifold off instead of just the air filter. Looks like I have to pay for a tow and have it fixed at a shop. Because it's an automatic there is no way to get the car started. All there is is that telltale loud click.
Yup, seen it in a Youtube video. Most likely one of the copper pieces has sailed off because no matter how often I try it will not establish contact and crank.
Hurumph ... grumble ... grumble ...
-- Regards, Joerg http://www.analogconsultants.com/
sh
rom
se
yep that's the symptoms, some times a great big wack with a piece of wood will make it work a few times
it's only held on with two 8mm bolts from the end, afair the problem is that you can't see what you are doing
one of them gets eroded by the sparking I guess, eventually it is so thin the disc can't reach it
-Lasse
Interestingly the color we see doesn't matter. Paint can have totally different properties at different wavelengths. There is black paint which is 'white' if you look at it with an infrared camera.
-- Failure does not prove something is impossible, failure simply indicates you are not using the right tools... nico@nctdevpuntnl (punt=.) --------------------------------------------------------------
You obviously never had to run an IT department. Connector problems cause 99% of the failures. And a network often had quite a few connectors between the switch and the device. In most cases one cable from the switch to the patch panel and then one cable from the outlet to the PC. That is 4 RJ45 connectors between the switch and a PC!
-- Failure does not prove something is impossible, failure simply indicates you are not using the right tools... nico@nctdevpuntnl (punt=.) --------------------------------------------------------------
They looked more like 6mm to me. Problem is that at least one needs to be loosened from underneath the car and the wire from the start relay also connects from below. There is all sorts of structurally important stuff between that and the bottom, no way I can reach that. What a pain.
This was all so easy on my old Citroen 2CV. You could reach just about anything directly.
-- Regards, Joerg http://www.analogconsultants.com/
Not really. People do. At least that's what IT pros told me.
Best one was in the late 80's, the days of coax Ethernet. "But I needed a 50ohm terminator real quick!"
[...]-- Regards, Joerg http://www.analogconsultants.com/
It does matter, however it's not all that matters. A black (optically) car will absorb more energy in the visible range than a white car. As you point out, what it does in the IR range can't be deduced by the "color" in the visible range.
arsh
from
C efuse
.I did all from the top standing next to the car, problem was turning bolt one turn at a time with a spanner feeling the way, can't remember if a socket wouldn't fit or I just didn't have one
once you have two bolts off you can get out to where it is easy to get the rest off
-Lasse
I just called someone who recommended a local shop so I'll do the decadent thing and just have it done. The American Corollas have all sorts of emissions control stuff hovering over the engine. It looks like an aircraft engine in there. Without taking a lot of that off I couldn't even reach in to feel a socket wrench into position.
-- Regards, Joerg http://www.analogconsultants.com/
It probably works ok when the vehicle is moving and there's plenty of air flow. The thermostatically controlled fan on the radiator will help with the air flow when it's not moving. There was a program to reduce the amount of copper (wire) used in automobiles a few years ago. I suspect mounting the black box on the engine is one of those copper saving measures[1]. Part of this is my nightmare come true:
Ever get the feeling that some vehicles were never designed to be repaired by mere mortals? There are only so many places on an engine where one can locate a starter motor along the circumference of the flywheel.
Stainless on stainless has the amazing ability to be self corrosive.
In fact, stainless steel can be both anodic and cathodic to ITSELF. This means that a single piece of stainless can act as a galvanic battery and promote its own corrosion. Corrosion in a marine environment is tricky but not impossible. Marine radios tend to be fairly well protected. However, in the distant past, I designed parts of the AN/SRD-21 and 22 direction finders for the US Coast Guard. Aluminum box and stainless hardware initially did a great job of corroding everything together. The big surprise was that nobody ever told us that the radios were going to mounted on the exposed bridge of a 42 footer. Standard procedure is to hose down everything with a "clean" water hose. A 60 PSI water jet can do an amazing amount of damage to the front of a radio, such as cave in the displays and shred the loudspeaker.
Tying down everything on a vessel is required as the rolling motion of the vessel will eventually turn any loose articles into flotsam or jetsam.
I've experimented with various potions trying to harden the goo. No luck yet. It's an amazingly common problem. I won't buy anything with a simulated rubber painted coating as most of them disintegrate eventually.
Nope, Elbonia:
One of the other engineers wore the hat and beard to a meeting. The design was quite good for the amount of time allowed. However, the company also had the PCB and packaging done in India. While the design company was sufficiently experienced in circuit design to do a decent job, the packaging and PCB layout were a mess, and may have been done by a sub-contractor. Both eventually had to be redone. That's also the source of the RJ45 arcing problem.
Incidentally, the original package was an amazing example of a box that could only be built by left-handed assemblers. I didn't believe it until I tried it myself.
I'm a bottom feeder, cleaning up the mess of others, doing what nobody wants to do, and deal mostly with dysfunctional companies. Nobody hires me because I'm the best. They hire me because they're in a hurry, desperate, cheap, need a scapegoat, or completely clueless. Most commonly, I get involved when there's a feud between two departments that are not on speaking terms. If I were to insist on an air tight definition of completion, the endless negotiations necessary to finalize a contract would take forever. I've picked up a few consulting jobs after a reputable consultant burned up too much time in negotiations.
[1] Everything is a conspiracy.-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
I think the 42V stuff has fizzeld, as expected. But mounting electronics on top of a motor is real stupidity, one just does not do that.
In this case there would have been space towards the radiator, but ...
Ouch!
[...]
:-)
Sounds like the Toyota here, except you also need skinny arms.
[...]-- Regards, Joerg http://www.analogconsultants.com/
Yeah, sorta. I don't run an IT department. I do run a consulting biz that in the past has wired various buildings, offices and homes for ethernet. I've also helped setup server farms for an ISP. Lots of connectors involved. I've seen failures, but they were never due to contact failure. It was almost always failure of the insulation displacement connection on the jack, crimping failure on the plug, wrong plug type, and shredded cables. Most customers insist on having the wiring tested with a cable certifier to detect split pairs and other wiring screwups that don't show up on continuity tests. All my crimpers are ratcheting type, which is required for a decent connection. Lots of other precautions, such as pull tests. After installation, the wiring is again tested using diagnostics built into the managed switch.
When I inherit a new system, I run the certifier though the wiring and usually find problems. Usually, it's bad patch cables with miserable crimps to the plugs. Lately, I'm finding really awful RJ45 plugs that really can't be properly crimped. I sometimes find stranded wire RJ45 plugs used with stranded CAT5. That won't work (although the reverse will work).
I rarely see any "failures" that could be directly attributable to the connector unless the connector was mechanically damaged. If I had to assign the blame, it would be with whomever built the patch cable or installed the wall jacks.
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
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