Entropy

Relax in southern comfort on the east bank of the Mississippi. You're just around the corner from Beale Street and Sun Records. Watch the ducks, throw back a few and tell us what's on your mind.
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JR.
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Re: Entropy

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Well, I just finished rebuilding my chainsaw... I suspect if I paid myself minimum wage I would have been better off buying a new one, The fuel lines were trashed by ethanol, and the saw has been hard to start for years. When I took the carb apart to rebuild I found a few blocked internal passages, one maybe blocked jet.

So now it should be good until the next hurricane drops some more trees in my yard. I have some big pines that need to come down, but not something I can handle with power lines and a little thing like my house too close nearby.

=======

I got my UV-C killer beam weapons working. I put one 9W lamp inside my room sized air filter, and the second one on a base that I can move around. I need to be careful with this since UVc light can burn skin and eyeballs, while it doesn't take much to block it. In fact I removed the extra layer of hepa filter from my air filter since it didn't make much sense to trap particles on the outside, while the UVc lamp is on the inside.

Coincidentally ozone blocks it , and the lamps can make ozone if they put out shorter wavelength light... Something like 250 nM for ozone-free bug bursting UVc, and the not very far away 185 nM makes nasty ozone.

According to the guy I bought the bulbs from they don't make ozone, but according to my nose they do. I asked the guy who sold the bulbs and he gave me a speech about how not everything from China is crap (that's my rap ), and it's even illegal to sell air cleaners that make ozone in CA.. I'm not shocked.

I am tempted to buy a premium brand name UVC bulb to compare and see if it doesn't make ozone.

I don't mind the ozone too much, it dissipates reasonably quickly after I turn it off, but it can be an irritant to lung tissue on top of the UVc melting my eyeballs. Danger will robinson.

I hope it does some serious damage to the mold I am chasing out of my bathroom.

JR
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JR.
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Re: Entropy

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Replaced the UV bulb in my water filter... not only did I pay too much for the bulb ($25) from the water filter company but I had to solder wires to all 4 pins on the lamp, Next time I replace this I'll buy a cheaper bulb from one of the sundry bulb sellers, and add my own push on pins or connector. It's a tight fit inside the quartz tube, but soldering every time seems like a poor design. They claim the bulbs should be replaced every year or less. Of course the bulb doesn't need to be on 24x7. THose wall times are getting cheap enough I may need to seen if I can extend the bulb life, several X by selectively powering it for when I expect to use RO water (morning coffee, etc).

=====

I forgot to mention in middle of trying to hold back the decay I experience personally, I fixed my UPS driver's headphones...he has a pair of closed back cans he used for attending NASCAR races and while mowing his lawn. The 3.5mm connector had a wimpy solder only attachment to the wire and that was not robust, so I put a real plug on it that allowed for mechanical and solder connection to hold the wire.

---------

I worry I would be tempting the fates, if I say I have nothing left to repair, but I actually do.. the check engine light on my car has been on for a few months. :oops: Always work to do...

JR
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Re: Entropy

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Not only could I predict this, but I did predict this... A few minutes ago while doing leg presses on my weight machine the main cable failed, so now 3 of the 4 stations are down. I can only do bench presses until I replace the cable. Ironically I was feeling bad about how the butterflies make my arms hurt (arthritis, not from the burn), but it could be worse, look at the cable. :lol:

This was already a pretty serious steel cable, I used thicker than than stock the last time I had to repair them. At least now I have the tools to crimp my own cables. Something that wasn't obvious to me the last time I replaced the cables is that bigger is not always better. Even pretty modest cable is not at much risk of shearing from my workout weights, but thicker cable works harder going around a given diameter pulley than the smaller cable.

So back to 1/8" or whatever was the standard cable diameter before.

Well now I know what was the next shoe about to drop... I can relax, and slide on the butterflies for a while... :D

Of course I just placed an order with McMaster Carr a few hours ago... arghhh. I waited two days to place that order so I wouldn't miss anything.

JR
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Re: Entropy

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OK, fixed the weight machine back in Oct and the smaller cable actually feels a little better, more flexible so goes around the pulleys with less friction.

Fixed a few things since I last reported in,,, one relatively simple fix, that was disproportionately rewarding was putting a new lock and doorknob on my tool room... I bought a new lockset a few years ago and never got around to replacing it because I couldn't get the old door knob off.. I was ready to take a hack saw to it, but found the catch to push in and get the knob off, that was painted over. Nailed it...

=====

My neighbor who was tired of listening to me talk about fixing stuff gave me an old leaf blower that wont start to fix or throw away... I took it apart and checked the regular suspects, it looks like it needs a carb rebuild, and I am too cheap to spend $15 on a rebuild kit for a throw-away leaf blower, so far but I may have to fix it on principle. While I generally find leaf blowers a scourge of the 20th century. Maybe I'll fix it so I can fire it up to compete with my neighbors when they run theirs. :lol:
...

OK this week's interesting fix... My sweet 84YO neighbor asks me to take a look at his old welder that won't draw an arc (he used to run a logging operation)... He said it worked when they last put it in storage but now it doesn't arc... How hard could that be? They thought it was the control PCB, a $1000 conformal coated roughly 8x10" thru hole controller (only 4 repair boards left in the country, its an old welder). I probed around in the cold poorly-lit shop and didn't see anything obvious but since it was a few minutes before lunchtime and my 84 YO neighbor is diabetic and needs to eat his lunch exactly at noon to keep his blood sugar up, I suggested he drop me off at home so I can look at the control board on my bench while he eats his lunch...

I rig up some AC into the board and confirm that the +/-5V supplies come up fine without catching fire or drawing excessive current, so I opine the control board is probably OK.

After lunch we go back to his shop and I start tracing out the wiring expecting a loose wire somewhere explaining the control board not having power, but the wires ring out good from the transformer, so I keep looking... BTW this is motor/generator/welder... so a two cylinder Honda motor in the back... the motor works and I trace the missing AC voltage all the way back to two wires coming out of the honda motor... While unlikely I told them the problem looks like it's inside the honda motor...

Then they decide to share with me, that a open box of nails fell down inside the welder and a half dozen nails got wedged behind the flywheel and jammed up the works.. SOMETHING THAT THEY COULD HAVE TOLD ME SOONER.

So I had them take off the flywheel and the motor has 3 magnetos inside the flywheel, one for each spark plug, and one to power up the control electronics, I guess the transformer up front was a step down transformer from the magneto voltage. Well the suspect magneto was beat up pretty bad and the coil winding was broken off from fly lead.

I cleaned up a few turns of the coil that were nicked by the nails so they wouldn't form a shorting turn, and soldered up the wire to the coil end.

Presto now it draws a nice arc and works fine... If they told me about the nails chewing up behind the flywheel I would have looked there first... It was as if they were testing me...and had me start looking as far away from the actual problem as possible... :D

I told my neighbor not to tell anybody I fixed his welder so I don't get more calls to fix broken stuff... but I have to admit it feels pretty good for my old neighbor to now think that I'm actually good for something.

JR
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Re: Entropy

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As proof that no good deed goes unpunished, while I told my 84yo neighbor not to tell everybody that I can fix stuff after repairing his welder, that didn't stop him from asking me to look at his electric scooter chair battery charger. :lol:

Long story short it is a 3-4A 24V pretty serious charger. A PIC microcontroller inside with two to-220 power SCRs. A pretty healthy transformer to support 75W+ output.

While I didn't trace out the entire schematic it was through hole so not that hard to follow. I determined that the PIC micro was coming up and working, it was able to detect when the charger was connected to a battery, just not charging it.

Working backwards from the SCRs they were not getting any gate drive, so backwards from there, a transistor follower buffered a 1/4 LM324 opamp configured as a comparator to gate the SCRs on/off. The + input to the comparator was supposed to get a ramp-sawtooth generated by a pull-up R, C to ground, and a transistor pulsed to reset the sawtooth.

In a rather obscure failure I found the 820k 1/4w pull-up resistor was completely open circuit. I think i may have seen a similar unstressed resistor failure like this only once before in several decades of repairing stuff. I didn't have the exact value but stuck a 910k from my parts bin in the circuit and presto the SCRs started switching again.

I was loading the charger with 3x 9V batteries in series to get close to 24V and they immediately rose up to around 30V dc. Since these were not rechargeable batteries I didn't leave them charging as it probably wouldn't end well. :o

I heard back today from my neighbor that the repaired charger charged up his chair batteries fine, and LEDs stopped blinking to indicate full charge.

I had to scrape up some shoulder washers to secure the SCRs to the heatsink, since they were loose when I got it, and one set of hardware was completely missing. My neighbor took the charger to somebody else to fix before me...and they apparently gave up declaring it unfixable. 8-)

and the beat goes on........

JR
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Re: Entropy

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It should be no shock, that I got tapped to repair my same neighbors riding lawnmower. Actually I volunteered after he gave up. The charging system was not keeping his battery charged and he had already sunken $70 in replacing the "regulator" (measures like a couple diodes).

First thing I noticed was his DIY fix for the starter solenoid, he apparently jumped a switch across it to directly feed the starter motor (including the voltage drop from a few feet of higher gauge wire).

After probing around the voltages coming from the magneto coil and after the rectifier, looked a little low, but biggest problem was that the charging wire was connected to the wrong terminal on the starter solenoid. Instead of charging the battery it was charging the starter motor???

Now I need to get him to replace/fix the solenoid, since eliminating his DIY fix voltage drop will help make it easier to start.

I never got a straight answer about how that wire got connected so wrong. Apparently an old fix for the starter that made something else not work.

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Re: Entropy

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More entropy updates concerning decay that surrounds me.

yesterday I was going to mow some of my weeds thriving before the grass starts growing, but I noticed a flat front tire, so I whip out my still shiny (made in china) hand pump..only a year or two old. First thing I notice is a horrible scraping sound, so I work some oil into the small hole on top. After a few hard pumps, the cylinder separates from the base... I also notice a crack in the plastic base. After fashioning a clamp out of two smaller hose clamps rigged together I am still not filling up the tire. So next step is to drop 4 quarters into the air machine at the local gas station. After pushing $1.00 of air through it I never manage to get the tubeless tire to make a seal with the rim and hold air. I find it impossible with only two hands to hold the hose on the valve stem, squeeze the release trigger, "and" manipulate the tire to seal with the rim. Arghhh

I drive up to the mower shop in defeat to pay them some nominal fee to fill it with air, and they are closed... :oops:

=======
Thursday night after playing basket ball I do my food shopping and while ready to drive home I notice my headlights are not on. The dash lights are fine, but I walk around in front of the car and both headlights are out. Not good... I try the high beams and they work. After toggling the high beams on and off a few times the headlights come on.

I guess this is what I get for driving a '97 model. From talking with my brother I learn it could be worse. In Europe they have "love the planet" recycling rules, covering all car parts. Mercedes changed to biodegradable wire insulation in the wiring harness, but apparently after less than 10 years the wiring is already bio-degrading to the point that wiring harnesses short out and need to be replaced. Yup, another case of our government helping us.

JR
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Re: Entropy

Post by emrr »

Geeez, 'green' should not be used as another excuse for pre-planned obsolescence, it should be used to build stuff that lasts as close to forever as can be managed.
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Doug Williams
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JR.
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Re: Entropy

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I'm guessing the mercedes bio-degradable wires were a miscalculation.

===

I need to make a correction, my cheap tire pump that fell apart was made in USA. Go figure... Not much to it. A molded plastic bottom, that cracked, a cheap steel tube and plunger. I glued the cheap parts back together, and wrapped a screw clamp around the base to help hold it together.. For now it is pumping air again, at least for modest pressure.

I had my local mower shop drop a tube into the tubeless tire so It's working again, the tube had a too long valve stem that hit the cotter pin holding on the wheel and made the axel cap fall off (and get chewed up. I managed to bend and get the cotter pin tight flush to the axel so new cap should stay on. (I hope).

It's always something :lol:

JR
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Re: Entropy

Post by emrr »

I have a poplar tree that's only come back about half way this year, looks like I'll have to $$$$ take it down. They sure like to throw heavy shrapnel in a strong wind, and it's that season.
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Doug Williams
Electromagnetic Radiation Recorders
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