Help with things el...
 
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Help with things electrical please - Position Sensor fix

cyclehead
(@cyclehead)
Honorable Member

I'm struggling to reproduce a repair trick that a kid in Moscow did on his Spyder.  Triz said he has done it also.   The position sensors crap out, send jumpy voltage to the TCU and it goes nuts.   The "fix" is to remove the conductive strip from inside the position sensor(s), scrub the surface with a pencil eraser, then restore the conductive surface with a #2 pencil.   

So I have disassembled a bad sensor, and I'm scrubbing.   Any ideas if I'm removing bad crap from the conductive surface?  Are the original shiny tracks just polished conductive stuff?  Or are the shiny tracks a build-up of crud to be removed?   What's coming off onto my eraser, good stuff or bad stuff?

Any help is appreciated!

The upper track has been scrubbed with the eraser.  The lower track is "as removed".

295E5C35 E3BA 4DBA B926 95B0A6DDC540
83931F8B 9985 40BE A67A 623347EACCF5

 

I make Amateur Armrests - see the Commercial Forum. I also have SMT repair seals available.

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Topic starter Posted : July 2, 2020 4:59 pm
cyclehead
(@cyclehead)
Honorable Member

 

E1DE8591 8295 49B5 8AF7 CAF1CE5B9EFD
C25B568E B71C 43F6 A278 BD264B23F835
4793E6C8 44F3 46F9 9DD4 5D538A6FA840
503C5592 0FA8 4A93 972A 7AA858E933C2

more pictures from the disassembly...

I make Amateur Armrests - see the Commercial Forum. I also have SMT repair seals available.

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Topic starter Posted : July 2, 2020 5:02 pm
cyclehead
(@cyclehead)
Honorable Member
0E444AB8 3558 4568 A2A3 2F81B1AE4300

I make Amateur Armrests - see the Commercial Forum. I also have SMT repair seals available.

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Topic starter Posted : July 2, 2020 5:09 pm
cyclehead
(@cyclehead)
Honorable Member
80D1E75A BE6E 48D1 AD71 4FF6B6FB4BD4

I make Amateur Armrests - see the Commercial Forum. I also have SMT repair seals available.

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Topic starter Posted : July 2, 2020 5:28 pm
Uncle Mush
(@uncle-mush)
Member

Hi Cyclehead . . . Please remember I know nothing about any of this kind of stuff.   There's my legal disclaimer.   Sometimes the contacts on the ink cartridges in my printer get grunged-up with grunge you can't even see and prevent the printer from printing.  I used to replace the cartridge and discard the non-working one.  Then I started using the eraser trick and most times that would do the trick to get the ink cartridge working again.   I got to where I would automatically do the eraser trick when installing new cartridges with fewer breakdowns.   Don't know if that helps any,  but thought I'd pass it along, just in case.

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Posted : July 2, 2020 10:28 pm
RIA
 RIA
(@ria)
Estimable Member

I'm no expert but I'd say you might be on to something. I made a transistor with a sheet of paper and a pencil once though if that does anything for you lol. Hope it works.

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Posted : July 2, 2020 10:34 pm
Petrus
(@petrus)
Reputable Member

Beejeezus, and then am I struggling with the idle being too high. I am sériously in awe 😲 

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Posted : July 3, 2020 4:34 am
(@suoiruc)
Trusted Member

I believe that’s the variable resistance strip which I think is graphite. That’s also the part that gets contaminated with brake fluid. I think it just washes away the graphite. My guess is some of the wiper material gets left behind and imbeds in the graphite making it shiny. Erasing it might be enough although it might remove some of the resistor. Don’t see the pencil lasting long but it’s worth a try. I was amazed at how delicate the wiper is and how it barely touches the resistor.

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Posted : July 3, 2020 5:42 am
CSPIDY
(@cspidy)
Reputable Member

They make a spray graphite in a can. You may need to bake it at 200 degrees for an hour or 2.

I have done this method to replace the graphite coatings on rods.

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Posted : July 3, 2020 4:25 pm
suoiruc reacted
cyclehead
(@cyclehead)
Honorable Member
Posted by: @cspidy

They make a spray graphite in a can. You may need to bake it at 200 degrees for an hour or 2.

I have done this method to replace the graphite coatings on rods.

“Dry film lube” correct?   I’m pretty sure the circuit is printed on Mylar sheet.   Can Mylar take the heat of baking?

I make Amateur Armrests - see the Commercial Forum. I also have SMT repair seals available.

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Topic starter Posted : July 4, 2020 6:23 am
CSPIDY
(@cspidy)
Reputable Member

Yes dry film, maybe try 100 degrees for 3-4 hours. Like slow roasting.

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Posted : July 4, 2020 3:11 pm
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