Help each other Fixit Log

What skills to learn, what tools to get
UK-with-kids
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Re: Help each other Fixit Log

Post by UK-with-kids »

All of my attempts at soldering have basically melted the plastic sheet and now it has holes in it :( :oops: I did get another batch of keys working for a while as a lucky strip of solder joined a gap up until it broke off again.

The sanding didn't seem to go very well either.

I've tried foil, and I've even mixed up a charcoal paste to try and stick a conductive line over the break, but it never seems to make a connection.

I think I will buy of those pens and see how I get on. At least I can't do any more damage that way. But after putting all this time and effort in I'd kind of like to at least fix the problem at the end of it all. :roll:

UK-with-kids
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Re: Help each other Fixit Log

Post by UK-with-kids »

Here's the mess I made of the plastic sheet when I tried to solder it.

Image

UK-with-kids
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Re: Help each other Fixit Log

Post by UK-with-kids »

But to finish with some great news, the conductive paint tube arrived and I managed to fix it in about 5 minutes. I turned it over from the earlier pictures and I scraped the green film off with a mini screwdriver.

This did cost me £11.69 for the tube including shipping, which wasn't really worth it just to fix this toy. However, if the tube of paint lasts a while then hopefully I'll get some more value out of it with other repairs. And I got a huge feeling of satisfaction in completing the job and I've learnt a lot from this project. My daughter was also ridiculously happy about it :D

Here's the fix with the tube visible in the picture too. The left-hand line had to go around the hole as I had caused so much damage with my soldering attempts.

Image

CDR
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Re: Help each other Fixit Log

Post by CDR »

The cost of learning is always cheap if it reduces your future expenses! The other benefit is that you've recorded the solution for the benefits of others. Now if I ever have a problem with electronics on a plastic film, I am going to think of your post, and get a conductive paint pen!

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Sclass
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Re: Help each other Fixit Log

Post by Sclass »


CDR
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Re: Help each other Fixit Log

Post by CDR »

Nice find, that will cut costs even more!

Alphaville
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Re: Help each other Fixit Log

Post by Alphaville »

Sclass wrote:
Thu Sep 24, 2020 6:06 am
I found this.

https://youtu.be/W_ouYLeIkoo
brilliant. i wonder if it could also be drawn with a soft graphite pencil, for those of us who have those things at hand already?

i’d test, but my multimiter died...

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Sclass
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Re: Help each other Fixit Log

Post by Sclass »

Yeah. Or what about bbq charcoal? Or printer toner?

Alphaville
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Re: Help each other Fixit Log

Post by Alphaville »

what about cutting thin strips of aluminum foil, aligning them correctly onto packing tape, then “stamping” the array on the circuit lines? might be a bit tough if the strips contact prematurely.



as for other charcoal, rather than a fireplace, maybe burn matches?

art charcoal also is finely burned wood... i think birch. again, if you can’t light fighes at home without summoning the fire dept.


oh! the cores of aa, c & d batteries! used to be graphite in my prehistoric childhood. no idea about these days.

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Sclass
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Re: Help each other Fixit Log

Post by Sclass »

Alphaville wrote:
Thu Sep 24, 2020 7:38 pm

oh! the cores of aa, c & d batteries! used to be graphite in my prehistoric childhood. no idea about these days.
Of course! I think they are still carbon on cheap batteries. This is cool because you can recycle dead ones!

I totally forgot motor brushes. I have some dead motors in my junk pile that have carbon brushes.

Alphaville
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Re: Help each other Fixit Log

Post by Alphaville »

ha ha i love this board.

btw i was searching the web for “thin electrical conductors” and read that... concrete is a conductor???

https://www.thoughtco.com/examples-of-e ... ors-608315

whaaaaaat? first i hear of this...

it’s lies, isn’t it?

UK-with-kids
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Re: Help each other Fixit Log

Post by UK-with-kids »

I did try sticking thin strips of foil in place, which I had partial success with, and I even ground up a charcoal art crayon into a paste after finding one of those videos, but that didn't seem to work at all for me. In the end the conductive pen made things very easy in comparison.

Although I was a bit annoyed at spending the money, it's not so different from buying any replacement components or tools. Yes it would have been great to make my own conductive paint, but where do you draw the line? I've never made any other types of paint, pens or glues even if theoretically I could have done. The better solution would maybe have been to find somebody who already had a pen and borrow it to use that tiny bit of ink. Ironically when I used to have a job they would have had that exact item in the workshop I think.

Anyway, the positive thing to keep in mind is that 99% of people would have thrown the toy away but I've fixed it and developed some great skills and knowledge in the process.

Now I'm wondering if I can use that pen to fix other bits of technology for people, maybe for charitable purposes rather than as a side hustle, but you never know!

Alphaville
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Re: Help each other Fixit Log

Post by Alphaville »

oh, art charcoal didn’t work? damn.... i was hoping it would save me in an emergency some day.

one thing i was thinking about after the charcoal video is that while it’s conductive it’s not as conducive as the metal film and increased resistance would either a) not work or b) wear out batteries faster.

so something like that probably happened with the charcoal, or maybe art charcoal is the wrong charcoal (it was odd to see the guy testing charcoals like someone buying fruit at the market, but i digress).

anyway hm generating ideas is fun in and of itself. divergent thinking sort of entertainment.

as for further uses for the pen, i keep thinking of electrical graffitti and/or pranks messing with preexisting circuits :lol:

UK-with-kids
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Re: Help each other Fixit Log

Post by UK-with-kids »

Alphaville wrote:
Fri Sep 25, 2020 1:14 am
oh, art charcoal didn’t work? damn.... i was hoping it would save me in an emergency some day.

one thing i was thinking about after the charcoal video is that while it’s conductive it’s not as conducive as the metal film and increased resistance would either a) not work or b) wear out batteries faster.

so something like that probably happened with the charcoal, or maybe art charcoal is the wrong charcoal (it was odd to see the guy testing charcoals like someone buying fruit at the market, but i digress).
It might have worked if I'd been very patient and invested a lot of time and attention in the charcoal method. Or it might not have worked, and to be honest I was losing patience after the soldering disaster. One thing to be wary about with all those videos is that they paint a strip with their DIY paint and then "prove" it completes the circuit, but they do it while the paint is still wet! And obviously water conducts electricity pretty well - you have to be sure it's going to work once it's dried.

Alphaville
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Re: Help each other Fixit Log

Post by Alphaville »

water with electrolytes, yeah (eg salt). maybe that’s what they meant with “concrete is conductive” in that thing above.🤔

i’m still curious and would like to play with graphite just because. i need to install a bench (hobby bench) in this apartment, and get me some basic tools...

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Sclass
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Re: Help each other Fixit Log

Post by Sclass »

Alphaville wrote:
Fri Sep 25, 2020 1:14 am

one thing i was thinking about after the charcoal video is that while it’s conductive it’s not as conducive as the metal film and increased resistance would either a) not work or b) wear out batteries faster.
It’ll either not work or it’ll make the batteries last longer. Keyboard I/o usually pulls current through a 10k load into a digital input that sinks the electrons to ground. Adding a weak connection in the chain will limit the number of electrons. There is the whole reliability thing with the diy glue.

It is fun to think about it though. I actually need one of those pens to repair the heated rear window on one of my cars where I scratched the little foil wires while scraping off old window tint. One of these days I’ll buy one.

There was a conductive silver epoxy I’d use for commercial applications to ground components electrically and thermally to heat sinks a few years back. It was like the thermal grease under a processor but it was a two part epoxy mix. I didn’t suggest it here because it was expensive. Not something I considered in a mission critical piece of industrial automation gear.

I always wondered how it worked because if I visualized the metal particles floating around in the epoxy I wondered how they made sure they were in good contact rather than just suspended in the matrix not providing a good electrical path. This is kind of the same issue with the carbon pencil glue wet dry conundrum.

I think the takeaway from this is get your hands dirty and try stuff. Just because something doesn’t pay for itself on the first go doesn’t mean it’s a total waste. Stuff was learned. A mental investment. Tools bought and skills developed. If you keep drifting in that direction you will always put yourself in a better place over time. A lot of my projects are a wash but I end up with tools and skills (and *diy attitude) for the future challenges.

*getting in the habit of toss and replace is a slippery slope. It’s kind of like farming out services to a professional source on a micro scale. Pretty soon you lose capabilities. It may be more efficient for an instant in time but I think it integrates up to a terrible state. An example of this is the plastic recycling problem today where it is still more “efficient” to just make old plastic containers disappear and make new ones.

Alphaville
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Re: Help each other Fixit Log

Post by Alphaville »

Sclass wrote:
Fri Sep 25, 2020 11:05 am
It is fun to think about it though.
it’s a blast.

and thanks for the explanation, i was never very good at electronics but would like to learn more.

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Re: Help each other Fixit Log

Post by jacob »

If you like to live vicariously/get inspired by fixing stuff and perhaps learn a few things too, I recommend https://www.youtube.com/c/Mymatevince/videos ... it's very laid back (almost Bob Ross like) and he usually discusses his mistakes as well. His main focus is on consumer electronics.

Riggerjack
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Re: Help each other Fixit Log

Post by Riggerjack »

I haven't been checking in enough lately, it seems.

Back to the original problem with lights. If I understand correctly, you have two lights, one works, one doesn't. You tested, and both seem to have 12v.

The next step, is to ensure both have a good ground.

But this is a trailer. Trailers get the cheapest, simplest wiring and devices. I expect, if you pull the whole unit off the ceiling, it will only have one (12v) wire attached. Ground is provided by the mounting hardware to the chassis. Maybe, you will be lucky, and there will be a grounding strap from device to a chassis mount, but either way, this is what you need to check. The hardware should be clean, and firmly tightened.

You messed up your tester, so you can do that check with a screwdriver, disassemble, clean, and reassemble. I give you a 55% chance of this fixing your problem, w/o a tester.

....

Next, fried multimeter. Open the back of your tester. It only has the one screw on the back, most likely. Pull the back case, and look for the fuse, it's very small, glass tube style, like in cars of the 60-70's, but much smaller. Usually, there is a spare fuse taped to the back case. Change fuse, and reassemble, and test.

....

When troubleshooting simple DC systems, stay in voltage for most everything. Be sure you are in DC voltage at the right range.

If you need to check continuity, disconnect the battery from the system. Touching 12v with your probe while in continuity mode will pop that fuse at least, almost every time. If it doesn't, because you only hit leakage, you still get a false reading, as your tester can't tell the difference between leakage and signal.

When troubleshooting old DC wiring, the first thing I do, is find the ground straps, disconnect them, clean them up, spooge some dielectric grease on everything, and reassemble. Basic tools and a wire brush, or sandpaper, is all you need.

Give that a try and let me know what you find. Good luck!

Riggerjack
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Re: Help each other Fixit Log

Post by Riggerjack »

Also, on using alternative conductors.

In my misspent youth, one of the pranks I learned was to pull the distributor cap, and with a soft art pencil, draw a line from each contact, to the base of the distributor cap.

When one then tries to start the car, each sparkplug wire has a parallel circuit going to ground through the pencil line. The pencil line isn't a good enough conductor to prevent spark at the plug, but it is a good enough conductor to greatly reduce the spark, so the engine runs rough, if it runs.

So graphite does work, but I wouldn't use it as a repair on anything, I rather tend to look at it as a potential problem. Graphite makes a good lube on smooth, hard surfaces, but then, remember that it's conductive, so watch for where it can go after application...

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