# Parma 90 ohm resistor questions.



## smalltime (Jun 3, 2006)

Hey all,
I've been having difficulty with my parma 90 resistors. I've mounted three of them in the last year. I'm using a parma turbo frame, with the usual mods. No brakes, light wire on the wiper, that's about it.

I've done dozens of these things over the years using the 100 ohm claristat, as well as the Ohmite. They work fine and I haven't needed to open them up for five years. But the one with the parma 90 has gone thru three resistors in a year. All three have broken the wire where it is welded to the last band. All three were epoxied and sanded smooth as usual, nothing more.

Anyone else having this problem?

Should I contact Parma?

Thanks,
Tim Leppert
AKA smalltime


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## sidejobjon (Jun 3, 2010)

*Test*

Off topic but how do you test OHM on controler?
Thanks SJJ


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## smalltime (Jun 3, 2006)

sidejobjon said:


> Off topic but how do you test OHM on controler?
> Thanks SJJ


Unplug the controller.

Set your trusty ohmeter to Ohms. (This sends a very small current thru the test subject.)

Clasp the test leads with your aligator clips on the end of your controller leads.

Apply just enough presure to move the wiper arm to the very first band on the resistor.

Read the meter.

And for an added check:
Apply full power. Read the meter. You are looking for it to read as close to 0 as possible.


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## Hornet (Dec 1, 2005)

Tim i have a new 15 ohm Econo,that's lost the wire on the top end band already,the controllers never been opened up.
I'd thought it was a fluke resistor,but if you've gone through a couple,maybe somethings changed at Parma
Rick


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## Bill Hall (Jan 6, 2007)

Count me in too Tim. Busted wire at the full throttle end on one of my 90's. Purchased last year-ish.


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## smalltime (Jun 3, 2006)

Hornet said:


> Tim i have a new 15 ohm Econo,that's lost the wire on the top end band already,the controllers never been opened up.
> I'd thought it was a fluke resistor,but if you've gone through a couple,maybe somethings changed at Parma
> Rick


That's what I'm thinkin'. 

This type of wire has to be welded, not soldered. There should be a spot welding type of setup for these. I'm wondering if they are trying something new or they are outsoucing to a new vender.


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## sidejobjon (Jun 3, 2010)

Thanks the test is cool. But now only 1 out of 5 reads right ohms.
How do i repair?
Thanks SJJ


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## smalltime (Jun 3, 2006)

sidejobjon said:


> Thanks the test is cool. But now only 1 out of 5 reads right ohms.
> How do i repair?
> Thanks SJJ


The repair depends on the problem.

The first thing to do is make shure the wiper is clean and in good order. 

The way I do a quik tune up is as follows:

Split your handle,

Take out the frame, being carefull of your wires.

Cut a peice of wet/dry type sand paper, say 800-1000 grit. Make it the same width as the resistor.

CAREFULLY slip the paper in between the resistor and the wiper, with the rough side towards the wiper.Make sure the paper is FLAT. Then simply work the trigger normally for about three to five minutes.

Slide it out, and reassemble.

That's the quick version.

If more is needed, we may have to start a "controller tips" thread, whatcha' think?


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