### Recent Posts

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##### Repair / Re: Asus B85M-G motherboard reboots with one second intervals
« Last post by janoc on Today at 06:32:04 am »
I applied power from the motherboard and carefully touched the every inch of the motherboard, but didn't feel any abnormal heat. I'm afraid I need to give up at this point. However, thank you everybody for sharing your knowledge!

You would need to provide a lot of current for anything on the board to get hot. Keep in mind that a computer motherboard is designed to take amperes of current on each rail, in addition to what the CPU and the GPU(s) take.
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##### Beginners / Re: Isolation transformer and electrons
« Last post by IanB on Today at 06:30:34 am »
Lets freeze the picture in time, when we have 120 V potential on the top and 0 on the bottom tap.

But this picture is wrong. The transformer output winding is isolated so we don't know the potential of any part of it. It is undefined. All we know is that one end of the winding is at a 120 V higher potential than the other.

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We are standing on the ground which is 0 V.

To be more precise, the ground is at 0 V because we have decided to use this as a reference.

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We touch the bottom tap and because it's 0 V

As noted above, before we touch the bottom tap its potential is undefined. We do not know what it is. After we touch the bottom tap its potential becomes 0 V, because we have connected it to ground and all connected parts of the system equalize to the same potential.

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and we are standing on the ground which is also 0 V, there is no current.

Naturally there is no current because potentials have equalized and there is no driving force.

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Now we touch the top tap which has 120 V potential and we are standing on the ground which is 0 V. Now what?

Before we touched the top tap its potential was undefined. After we touched the top tap its potential became 0 V, because we have connected it to ground and it will equalize its potential through the connection.

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You are going to say, yes there will be no current, because we have isolated system and we don't have a current loop to flow. Ok, but electrons do not know nothing about isolated system, they just see a voltage difference. So we are touching the top tap 120 V potential, and we are standing on the ground 0 V potential.

You are correct, there is no current because there is no circuit. But also there is no current because the top tap is at 0 V potential after we touch it, the same as the ground, so there is no voltage difference to produce any current.
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##### Beginners / Re: Transmitting CAN messages and ignoring ACK with MCP2515
« Last post by HwAoRrDk on Today at 06:25:18 am »
Added some code to output the value of the relevant TXBnCTRL register after sending each message. It always has the ABTF and MLOA flags set (TXERR is not set), meaning that the message lost arbitration during transmission and was aborted.

I don't understand, why would it lose arbitration when there are no other nodes on the bus?
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##### Other Equipment & Products / Re: REVIEW: Dental Surgical Binocular Loupes with LED Light
« Last post by cdev on Today at 06:23:10 am »
As somebody who has recently done this I can attest to the fact that almost any eye drop that is sold can have a tiny bit of pure l-carnosine added to it and that that will markedly improve vision for somebody who is a bit older. However, once you add the carnosine you need to throw the eye drops away in a few days, as carnosine is a amino acid derivative it may feed bacterial growth so I would be conservative and assume that once you start adding carnosine you should discard them in a few days and make new.

For 15 ml of saline eye drops, a very small amount of l-carnosine should be used, about the amount in a match head. I have no way of measuring how much I use, I always use the same amount, in volume, using a small measuring spoon, or estimating it visually. I always taste it first. L-Carnosine has a bland but recognizable taste. It is soluble in water.

Make sure its pure! Get it from a reputable seller.

However l-carnosine when used this way is extremely cheap since so little is used. Also if you use the cheapest generic eye wetting drops they are pretty cheap too, much cheaper than the $50 n-acetyl carnosine eye drops sold for pets that some people buy or the$45 for three tiny vials human version.

Note: L-carnosine is not as effective as the (patented) n-acetyl carnosine is in reversing eye yellowing by weight or by the drop, but the ultimate result is the same, and the cost differential makes it affordable for all even pet dogs who have major problems with eyes as they age, so knowing this is very useful.
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##### Projects, Designs, and Technical Stuff / Re: potting contacts
« Last post by coppercone2 on Today at 06:22:43 am »
you are changing the tension and probobly the oxide growth rate etc determined by the manufacturers at some tension level. and the resistance/power handling/dissipation.

i think it will be more stiff since the spring has less effective room to travel/free space is now gummy.
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##### Renewable Energy / Re: When Will Electric Cars Become Mainstream?
« Last post by mtdoc on Today at 06:17:05 am »
Maybe I have to make really simple.  Always leaving the house with a full tank is what people are raving about.
But why is that necessary at all...? IMHO lack of range! If you do the math it is likely that an EV owner spends more time plugging/unplugging and searching for a parking spot with a charger than it would take to fill up an ICE based car every once in a while. A typical ICE has enough fuel left to travel 80km in any condition when the 'now I need a drink' light goes on. In cold winter conditions the range of some EVs drops to less than 150km (unless the driver likes to freeze to death). Range anxiety still is a real thing. OTOH I'm not going to fill up my car to the brim if there is enough fuel in the tank to cover the distance. And if there isn't enough I'll just stop somewhere for a quick refill. The whole 'plugging in everywhere is better than filling up once in a while' idea is utterly moronic if you really think about it.

More talking out the arse by someone who doen't own an EV and has zero personal experience with them.

Most BEVs now have range close or equal to ICE vehicles - so "filling up" daily is not necessary.  But why not fill up daily when it is cheap and painless?. Why do I plug my phone in every night even though in reality a charge can last several days?

I have a friend who recently bought a Tesla Model 3. She does not have a high level charger installed yet at home and originally thought she would use the free public charger a block from her office to fill up once a week.  But it turns out she says it's just easier to top off the batteries every night at home with the 120V charger that came with the car.  And over the recent Thanksgiving holiday, her and her family drove it 350 miles each way to visit family. No problem.

Again - your constant nonsense is just like all the ranting a few years ago about all the short comings of DSOs by people who had never actually used one.  In the end it turns out there are only a few niche areas where analog scopes have an advantage over DSOs.

EVs are now mainstream. As time goes on the edge cases where an ICE vehicle is the better solution will become a smaller and small subset of all vehicle use.

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##### Repair / Re: Asus B85M-G motherboard reboots with one second intervals
« Last post by m4rtin on Today at 06:16:34 am »
I applied power from the motherboard and carefully touched the every inch of the motherboard, but didn't feel any abnormal heat. I'm afraid I need to give up at this point. However, thank you everybody for sharing your knowledge!
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##### Test Equipment / Re: Service manual for Fluke i50s / Lem PR 50 current clamp
« Last post by 0xdeadbeef on Today at 06:11:51 am »
This would be great. Also any input on my idea to use that trimmer for gain correction would be appreciated.
And I'm still not 100% sure how to remove the label on the backside without damaging it. Heat maybe.
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##### Projects, Designs, and Technical Stuff / Re: RC2014 Retrocomputer Boards I've Designed
« Last post by rstofer on Today at 06:07:43 am »
I have a couple of the RC2014 kits including the one for CP/M.   They are a lot of fun to build but I haven't found an application.  I have a 50 MHz Z80 version of CP/M and it is FAST!  But I still don't have an application.  Maybe one day...

I did build the T80 FPGA clone of the Z80 and it is currently running PacMan.  I just haven't got room for the bar table that would complete the project.
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##### Metrology / Re: What are these boards from? Who can make sue of them?
« Last post by Edwin G. Pettis on Today at 06:07:21 am »
Sorry, the resolution is insufficient to 'read' any part numbers, can you do a zoom in on some of them or just write the numbers down.  Even the board numbers are a bit difficult to make out.  Without more information I can't make any identifications.
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