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The elusive early TR dash light rheostat

Discussion in 'Boxers/TR/M' started by V4NG0, Oct 21, 2020.

  1. V4NG0

    V4NG0 Karting
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    Dec 14, 2018
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    Looking for parts NLA
    This part has been confirmed as NLA for some time. Rather puzzling is the fact that two reputable Ferrari parts specialists couldn’t even give me a part number for it. A search of table 118 shows the part in the drawing, but provides no reference to it.

    Does anyone know any of the following:
    1. The part number?
    2. Where to purchase one new?
    3. Where to purchase one used?
    4. Where to refurbish one?
    5. Or if a rheostat from another model will work? For example, the part clearly shows in table 121 for a 512TR, part number 131467. Or will a period 328 or Mondial one work?

    This is for a US spec ‘86 TR where the dash light rheostat is located in the middle tunnel down low next to the odometer.
     
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  3. Veedub00

    Veedub00 F1 Rookie
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    I’m willing to bet it’s a common fiat part.
     
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  4. campbell360

    campbell360 Formula Junior
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  5. V4NG0

    V4NG0 Karting
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    Dec 14, 2018
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    Looking for parts NLA
    Thanks for the tip. That’s the same part number as for the 512TR rheostat. On the linked diagram, however, it shows the rheostat located in the dashboard by the speed/tachometer. My rheostat is down low in the center by the odometer. I don’t know if this placement makes a difference, but if my history of sourcing early TR parts is any guide, it does make a difference. Can anyone confirm?
     
  6. c4b4the04

    c4b4the04 Formula Junior
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    I am no expert, but I have a feeling it is a linear taper potentiometer, and those would be available from any electronics supply house. If it were mine, I would pull the unit, read the numbers off the casing and call somewhere like Mouser Electronics. There are likely only a few wires connected and they wouldn't be hard to transfer over. Thinking outside the box. The joy of this car is that these are usually common parts underneath the expensive F car parts.

    Hope that helps. The other thing you may want to try is a good contact cleaner. I use Deoxit, but there are lots on the market. You may be able to revive your notchy/semi working one, if that is the case.
     
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  8. ago car nut

    ago car nut F1 Veteran
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    I was able to clean the oxidation from mine with a pencil eraser.
     
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  9. c4b4the04

    c4b4the04 Formula Junior
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    Is the AC/Heat switch the same way?
     
  10. ago car nut

    ago car nut F1 Veteran
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    I don't know, I keep mine on MAX cool.
     
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  11. V4NG0

    V4NG0 Karting
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    Looking for parts NLA
    Thanks for the good input. You are probably right about that, and I like the idea of sourcing a donor part. I was hoping to have an update on it being pulled and analyzed, but the car is hung up at the service shop right now with a different issue.
     
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  13. V4NG0

    V4NG0 Karting
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    Looking for parts NLA
    Thanks for the idea. Do you have more info on this remedy and/or pictures by chance?
     
  14. ago car nut

    ago car nut F1 Veteran
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    Just used the eraser to gently remove the oxidation from the copper, I believe I had to disassemble it.
     
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  15. Steve Magnusson

    Steve Magnusson F1 World Champ
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    Will just add the comment that rotating it once in a while (to wipe the brush over the windings) will help keep it healthy (vs leaving it in one place for 3 decades ;)).
     
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  16. Gary Sandberg

    Gary Sandberg Formula Junior

    Stupid comment to add, but I rarely drive at night and the last time, went to use the rheostat and turned it to the right - no response, after several tries.

    Turned it to the left and the dash lights came on perfect. So, ignorance on my part at its best or Italian engineering at its best. :confused:

    Take your pick.;)
     
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  17. V4NG0

    V4NG0 Karting
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    Looking for parts NLA
    Thanks Steve for the maintenance tip!
     

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