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PirateDentist posted:Yep. Mine was cut off my 4runner a few weeks ago. Out $300 so far and still fighting one stupid nut to get the end of the pipe off the header. They cut the upstream O2 sensor wires as well, even though they didn't cut that part off. So I have to solder those back together as well. Do NOT solder O2 sensor wires if they are not copper. Hopefully they are after the connector that was cut off. If the wires are silver (i.e steel wire) you need to find the right crimps.....and those are not the ones that you have at the parts store. They are the kind that come with "universal" o2 connectors.
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Jul 24, 2021 04:21
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PirateDentist posted:Yep. Mine was cut off my 4runner a few weeks ago. Out $300 so far and still fighting one stupid nut to get the end of the pipe off the header. They cut the upstream O2 sensor wires as well, even though they didn't cut that part off. So I have to solder those back together as well. Uhm, you're not supposed to solder oxygen sensor wires. The solder joint will add resistance to the wire and screw up the signal. If you must repair them, quality crimp / heat shrink connectors should be used instead. If they're not super expensive, I would just replace them. e:fb
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Jul 24, 2021 04:26
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Black88GTA posted:Uhm, you're not supposed to solder oxygen sensor wires. The solder joint will add resistance to the wire and screw up the signal. FYI, it's not resistance......there is super low current coming out of an O2 sensor and they are very hot so wires close to it of different materials can create a thermocouple that makes actual power......throwing off the very little power coming from the O2 sensor that your ECU is trying to read. (this is a super simplified answer, tl'dr don't do this it will make a bunch of problems that are hard to diagnose)
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Jul 24, 2021 05:06
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Motronic posted:Do NOT solder O2 sensor wires if they are not copper. Hopefully they are after the connector that was cut off. If the wires are silver (i.e steel wire) you need to find the right crimps.....and those are not the ones that you have at the parts store. They are the kind that come with "universal" o2 connectors. Black88GTA posted:Uhm, you're not supposed to solder oxygen sensor wires. The solder joint will add resistance to the wire and screw up the signal. If you must repair them, quality crimp / heat shrink connectors should be used instead. If they're not super expensive, I would just replace them. Noted, thanks. I was not aware of that. I'll just buy a new one, so another $50 down the tube because of those fuckers.
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Jul 24, 2021 06:15
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So what kind of misbehaviour soldering the wires would have caused and how long it would have taken to diagnose it?
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Jul 24, 2021 12:36
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FIRE.
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Jul 24, 2021 12:46
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You can solder if it's done right. Generally automotive wiring recommends against solder for various reasons, non of which were described.
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Jul 24, 2021 13:50
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You generally don't want to solder because it hardens when it cools, and can crack from the vibration. If you tie the wires together properly and put heat shrink tubing on them they should be fine. I don't think you need to replace the O2 sensor because of it. Use a western union splice and put heat shrink over it and you'll be fine: 
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Jul 24, 2021 14:16
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I'm having difficulty putting the heat shrink over it after I made the splice, can someone help?
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Jul 24, 2021 14:46
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Well you have to put the heat shrink on before you solder the wires together.  But seriously just use bigger heat-shrink. Post a picture of the joint?
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Jul 24, 2021 14:51
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I crimped milcirc pins to mine and then soldered the pins and used adhesive heatshrink to hold it all together.
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Jul 24, 2021 14:57
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Saukkis posted:So what kind of misbehaviour soldering the wires would have caused and how long it would have taken to diagnose it? It would gently caress with the oxygen sensor signal going to the ECU so you'd see the same sort of stuff that you would with a faulty O2 sensor. Bad fuel economy, a little less power, funky smelling exhaust, and eventually a check engine light when the O2 sensor signal doesn't respond to various load conditions like the ECU expects it to.
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Jul 24, 2021 15:06
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The cat thefts have gotten so bad that all of Toyota's cats are on manual release. Which means dealerships are no longer allowed to simply order them for stock, or order them for a vehicle and have them sent right away like a normal part. They need to be manually checked to make sure the part number fits the vin, then it's recorded that the part was sent for that specific vin. For every manifold and pipe converter that Toyota makes. And that's assuming the part isn't on national backorder like about 25% of our parts are. Don't bother with OEM rotors, we probably don't have them. We're keeping our local NAPA in business solely through orders for rotors for 11+ Highlanders and Siennas...
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Jul 24, 2021 15:12
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Shifty Pony posted:It would gently caress with the oxygen sensor signal going to the ECU so you'd see the same sort of stuff that you would with a faulty O2 sensor. Bad fuel economy, a little less power, funky smelling exhaust, and eventually a check engine light when the O2 sensor signal doesn't respond to various load conditions like the ECU expects it to. Yes, soldering could eventually lead to that, and it wouldn't be immediate. The annealing/cooling process would lead to the solder becoming brittle, especially if it's lead free, due to proximity to the exhaust path. A properly spliced and covered connection will be fine. The splice that I posted is designed to be able to withstand changes in tension etc. The resistance of the wire is not going to be wildly fluctuating and will be well within the material specifications. An O2 sensor will have an internal resistance of 10-25 Ohms. An addition of a few mOhms is not going to change anything.
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Jul 24, 2021 15:23
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That's why I have two new sensors complete with their wanky looms. Not soldering poo poo.
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Jul 24, 2021 15:40
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It is not the resistance that fucks with the signal it is the EMF generated by inserting a junction of dissimilar metals into the circuit. It essentially is putting the O2 sensor in series with an uncharacterized thermocouple without a reference junction. It isn't a serious problem with other sensors because the signal voltages are high enough and/or the temperature difference across the harness isn't high enough to generate substantial emf, but a big swing in the O2 sensor signal is tens of mV and the sensor body is at over 600°F.
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Jul 24, 2021 15:48
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Minnesota Mixup posted:Yes, soldering could eventually lead to that, and it wouldn't be immediate. The annealing/cooling process would lead to the solder becoming brittle, especially if it's lead free, due to proximity to the exhaust path. A properly spliced and covered connection will be fine. The splice that I posted is designed to be able to withstand changes in tension etc. The resistance of the wire is not going to be wildly fluctuating and will be well within the material specifications. This is simply not correct. Again, due to the specifics of the environment an O2 sensor exists in, putting dissimilar metal (whether it solder or a crimp) creates a thermocouple, which produces voltage. The same way that the O2 sensor itself does by design. So now you're creating a dirty signal.
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Jul 24, 2021 16:38
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Saukkis posted:So what kind of misbehaviour soldering the wires would have caused and how long it would have taken to diagnose it? Don't solder. I did it on my stereo harness and the heat/vibration eventually caused intermittent crackling that I didn't realize it was my lovely solder job failing months later. Your engine bay and O2 sensor are more critical and in a more volatile area. https://www.youtube.com/watch?v=pOTrS6-mNtA https://www.youtube.com/watch?v=KTbNxhTzucU
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Jul 24, 2021 17:21
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Well, I certainly learned some things in there. I’ve always tried to solder vehicles wires over crimps but I also do a western union splice like above. I shall endeavor to crimp in the future instead. Guess I need to order a bunch of those fancy heat shrink crimps.
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Jul 24, 2021 17:52
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Motronic posted:This is simply not correct. Again, due to the specifics of the environment an O2 sensor exists in, putting dissimilar metal (whether it solder or a crimp) creates a thermocouple, which produces voltage. The same way that the O2 sensor itself does by design. So now you're creating a dirty signal. No. You will not produce enough voltage to have any impact on the O2 sensor reading. For instance, a type k thermocouple, made of chromel and alumel is specifically chosen due to it's high seebeck coefficient. At 200-400 C this type of probe will produce approximately 8-16 mV. O2 sensors are typically made of zirconium dioxide and will produce at a stochiometric mixture of combustion around 450 mV. That's a 2-4% difference. And that's assuming that you are soldering with type k material and doing it inside the actual sensor. It's negligible in the same way that the temperature gradient along the wires that connect the sensor are. If it were that sensitive they would require strict thermal controls to control the change in resistance with temperature. Solder itself however would be well within it's glass transition temperature, and will become brittle after many thermal cycles, and combined with vibration etc is a recipe for poor connections. It should outside of very special circumstances only be used when at least one side of it is a rigid structure, and caution taken to avoid strain. Crimps are fine, tied splices are fine. The signal isn't going to be 'dirty' because it's off by a percent or two. This isn't a measurement where analytical precision is required. Source: I have spent over a decade designing and creating analytical instrumentation, including some destined for space flight, with nearly every sensor under the sun, primarily producing sub uA/uV signals, with some in the fA/fV regime.
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Jul 24, 2021 20:29
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Minnesota Mixup posted:No. You will not produce enough voltage to have any impact on the O2 sensor reading. For instance, a type k thermocouple, made of chromel and alumel is specifically chosen due to it's high seebeck coefficient. At 200-400 C this type of probe will produce approximately 8-16 mV. O2 sensors are typically made of zirconium dioxide and will produce at a stochiometric mixture of combustion around 450 mV. That's a 2-4% difference. And that's assuming that you are soldering with type k material and doing it inside the actual sensor. It's negligible in the same way that the temperature gradient along the wires that connect the sensor are. If it were that sensitive they would require strict thermal controls to control the change in resistance with temperature. So your talking about this using experience you have that isn't an O2 sensor in a car? Because I've looked at this on a scope with multiple O2 sensors in multiple cars that were having this exact issue. This isn't a theory for me, it's direct observation. And I'm not the only person who has observed this exact phenomena, which seems even more pronounced when using the wrong crimps.
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Jul 24, 2021 20:36
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Motronic posted:So your talking about this using experience you have that isn't an O2 sensor in a car? Because I've looked at this on a scope with multiple O2 sensors in multiple cars that were having this exact issue. This isn't a theory for me, it's direct observation. And I'm not the only person who has observed this exact phenomena, which seems even more pronounced when using the wrong crimps. I am talking about fundamental laws of physics. It's a sensor that creates a potential. It doesn't matter if it's an O2 sensor or anything else, the same methods are used to measure them. If you create a poor contact through poor crimping or another method, yes, it will not function properly. No one is debating that. It has nothing to do with creating a nernst cell by accident. Or by having solder (before a poor contact/heating is introduced) as it would act in parallel or series over a small distance. Yes, if you have bad contact, either initially or through vibration/tension then it will not behave as expected. You cannot cite observational data such as that without controls and knowledge of the properties of the connections. I have seen soldered joints that have poor connections on circuits. Does that mean that solder should not be used?
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Jul 24, 2021 20:52
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So the answer is "no, I don't not have direct experience". But you do have a huge case of "well ackshually I'm an engineer" going on.
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Jul 24, 2021 21:00
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Motronic posted:So the answer is "no, I don't not have direct experience". But you do have a huge case of "well ackshually I'm an engineer" going on. Ok you're right, I bow to your experience of I've looked at cars with bad ones. Engineers are stupid and all that science is a waste of time. Anyway here's how I solder all my car wiring connections 
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Jul 24, 2021 21:09
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And to get the thread moving again: Somehow on the front AND backwards.
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Jul 24, 2021 21:11
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It's on the rear and forwards if you are driving in reverse!
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Jul 24, 2021 21:16
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Uthor posted:It's on the rear and forwards if you are driving in reverse! Brilliant, the cheapest way to turn your fwd car in to a rwd one! A classic that was recently posted in the randomwaffles thread: 
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Jul 24, 2021 21:21
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TIL that shirtless dude is still making music… https://youtu.be/8D7iT2MT00o …Even though no one asked him to.
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Jul 24, 2021 21:46
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MrYenko posted:TIL that shirtless dude is still making music… Yeah it's uhh, quite a change and also awful.
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Jul 24, 2021 21:46
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Minnesota Mixup posted:Ok you're right, I bow to your experience of I've looked at cars with bad ones. Engineers are stupid and all that science is a waste of time. I usually intertwin braided wires then solder them together so they look like one contiguous wire.
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Jul 24, 2021 21:52
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CommieGIR posted:I usually intertwin braided wires then solder them together so they look like one contiguous wire. Yeah that's pretty much SOP for things like that. Just that special attention is sometimes warranted in areas where the environmental temperature can approach the Tg of the solder or even Tm. It can just become brittle over time and in some places oxidize giving a bad connection. Since engines/exhausts etc aren't rigid it can cause issues long term. If materials etc were really such an issue it would suck because we wouldn't even be able to use things like connectors, or solder on PCBs. Fun fact: NASA has huge rooms where equipment can be mounted and put through the same vibrational frequencies of the rockets that will launch them to test for wiring/mechanical issues before hand.
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Jul 24, 2021 22:02
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Minnesota Mixup posted:Fun fact: NASA has huge rooms where equipment can be mounted and put through the same vibrational frequencies of the rockets that will launch them to test for wiring/mechanical issues before hand. I'll be disappointed if someone hasn't strapped their car to it.
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Jul 24, 2021 22:44
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Minnesota Mixup posted:
Well it's in the right thread at least. Do talk more about what you yeet off this rock though, fascinating stuff.
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Jul 24, 2021 23:23
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Gotta be honest when AI gets all crimp don't solder there's usually a link to a NASA wiring standards pdf. I can also count on the fingers of one hand the number of times a soldered wiring splice has bit me and or a car I've worked on with the fingers of one hand. I have lost count of the number of problems with twisted, twisted and taped, twisted and heat shrunk, and crimped, and loving wire nuts but that doesn't count, have caused. Crimped with heat shrink though has batted 100% but is the least common I've seen.
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Jul 24, 2021 23:49
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All the slap fight arguments about soldering vs. crimping are only valid if the job is done correctly. Which is better: a halfassed crimp done with the wrong size of terminal and a pair of pliers, or a dusty soldered joint done with a thousand degree wood burner and no flux? Cause both of those are far more likely on a PO car than a correctly executed anything.
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Jul 24, 2021 23:55
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Where do the all in one heatshrink/solder/seal jobbies come on that scale?
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Jul 24, 2021 23:56
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Sagebrush posted:All the slap fight arguments about soldering vs. crimping are only valid if the job is done correctly. This is actually what it comes down to. Most people say soldering sucks because they don't know how to solder. Or that you need the right solder for the right applications. Or strain relief. This is why the NASA PDF gets posted. If you can't be arsed to figure any of that out the answer is simple: it's not that soldering sucks, it's that you suck at soldering. On the other side of this, most people crimp wrong too. Wrong size connector. lovely connectors. Not using the right crimper, or any crimper at all.......
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Jul 25, 2021 00:02
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It's just no crimper at all from my experience. Just mushed with side cutters or vise grips. But I also was only looking when there were electrical problems so what's the opposite of survivor bias?
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Jul 25, 2021 00:16
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Sagebrush posted:
The crimp, because I can see it a lot easier and then fix it, rather than unravelling a wiring harness that I cant find a replacement for to try and work out where there's a soldering joint that is intermittent hidden under conduit and tape. And frankly most people who solder in cars are thinking that means it'll be a better connection while not for one second wonder why the loom they are spicing into doesnt have a hint of solder in it to start with ... and then wonder why their ECU is showing up weird outputs or it stops working a couple of years later when they should have done a proper breakout plug to install a signal interceptor style ECU upgrade but nooooo is like more work man and we dont have time for that poo poo The dodgy crimpers usually know they dont know what they are doing and that usually limits the damage because they only do minimal poo poo. The dodgy solders think they do and gently caress things up worse by going to town. Also its a drat sight easier to learn how to crimp properly than to solder. Maybe it's the excessive pain from what I'm avoiding due to previous owner stupidity trying to fix in my WRX project speaking but *gently caress soldering in a car's wiring*
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Jul 25, 2021 01:01
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cursedshitbox posted:Well it's in the right thread at least. Instrumentation to do accurate soil ion analysis on Mars. Previous rovers with wet chemistry labs used 'ion selective' electrodes. Except that they used these and found that they had more of the components than the total mass of soil that was tested. Turns out these ion selective electrodes aren't actually single ion selective and that perchlorate throws off the measurements in a huge way, and the soil of Mars appears to have a significant amount of it. So I worked to develop a compact method of doing what we would do on Earth to do the same on Mars. Power and weight are understandably severely constrained when it comes to space flight, especially somewhere distant like Mars. A system that we'd use for this here would weigh around 50 kg and consume several liters of liquid, which would need to be heated for the entire trip to keep it from freezing. Getting 1 kg of mass to low earth orbit costs ~$10,000, and it's way way more to get it to Mars. So I developed an instrument that weighs < 500 g, uses < 1 watt, and consumes ~10,000x less liquid. Other advantages are that because of the way it works it can go through freeze/thaw cycles without reduction in performance, greatly reducing power requirements when not in use. It's been moved on to engineers now to ensure that it's radiation hardened etc. Also fixed some problems with another project that was on-going while I was there to separate amino acids by chirality for exoplanet exploration in the search of evidence for why L amino acids are overwhelmingly preferred in terrestrial lifeforms as opposed to D. (Chirality is 'handedness,' your left and right hands are mirrors of each other but cannot be aligned on top of one another due to chirality). I do more boring stuff these days, as working for government agencies like NASA that are controlled by politicians can be a total nightmare, especially when the people in power move between 'we'll just kinda forget about them' and 'the earth is 6000 years old and space exploration angers god.' There were several contractors there that had been waiting 5+ years to try and get a civil servant job. I did get to meet several astronauts though which was pretty cool, including Jim Lovell. honda whisperer posted:It's just no crimper at all from my experience. Just mushed with side cutters or vise grips. Probably something like selection bias. Taking a non-representative sample, i.e. only cases where something has failed, and considering only those or placing a much higher weight on those. Tends to feed in to confirmation bias. You're already expecting that to be the result, and only see cases where it was the cause, so they work together to lead you to an inaccurate interpretation of the data. We don't tend to seek out causes of something working, only failing. Especially when it comes to repairing things that have failed. Also I agree that I'd rather have someone do a lovely crimping job than a lovely soldering job. You can hide the solder joints a lot more easily than the crimp connectors.
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Jul 25, 2021 02:08
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