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Author Topic: Potentiometer Questions  (Read 1851 times)

Offline beko1987

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Potentiometer Questions
« on: September 30, 2015, 11:21:29 AM »
What ho teccie chaps!

One of my long, long term projects is an Electrolux Dolphin Z2260. Lovely cleaner, bloody rare and also broken.

The speed control on the hose was broken when I got it years ago. I broke it in another place and its sat in the loft unloved. I fixed the main issue with it the other night, and am looking to fix the speed control. Initially, one of the pegs holding the potentiometer on was broken



My stepdad soldered it up for me, but still nothing. I'm wondering if I lost part of it back in the day when it broke originally.

Either way, I need a new one. I found this on ebay

http://www.ebay.co.uk/itm/2x-Piher-PT15NV-15mm-Trimmer-Potentiometer-Horizontal-25K-Variable-Resistor-PCB-/291550700143?hash=item43e1c6a26f, having spotted a 25k marking on the old one, and working out I need a Horizontal not vertical one as they look the same.

I also had a look at the datasheet on the attached listing, and I think I need one with a removeable shaft/rotor, it certainly looks roughly the same



but I know nothing about wiper settings, apart from on a car... I emailed them asking the same question as I have here (awaiting a reply), but does anyone know any better than me about what I potentially need?







Would be nice to get te old girl working right again, she's bloody rare!
Collector and restorer of vintage vacuums, Dyson Appreciator! Come and see my blog, where I am uploading all my mountains of brochures, manuals and other vacuum cleaner paperwork, and also my youtube channel @beko1987!

Offline beko1987

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Re: Potentiometer Questions
« Reply #1 on: September 30, 2015, 11:30:43 AM »
Message received -

"Sorry, we do not have any technical support, and are unable to answer technical questions'...

More googling to be done then
Collector and restorer of vintage vacuums, Dyson Appreciator! Come and see my blog, where I am uploading all my mountains of brochures, manuals and other vacuum cleaner paperwork, and also my youtube channel @beko1987!

Offline Tech12

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Re: Potentiometer Questions
« Reply #2 on: September 30, 2015, 12:04:04 PM »
A few questions: 1) Have you checked the pot with a multimeter ?   2) Have you checked the 2 resistors ? & 3 are the dimensions etc the same as the eBay one ?.
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Offline beko1987

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Re: Potentiometer Questions
« Reply #3 on: September 30, 2015, 12:35:47 PM »
I did check the pot, the solder didnt hold too well and did break off again, so I popped the cover off, and took out the inner adjuster, to reveal the inner. I'll have to grab a picture in a sec, but with the machine on, and bridging the 2 connectors within makes the speed slow down, as I presume it should. The pot itself doesnt have continuity, but all the places it conencts to on the back of the PCB have continuity. The resistors have continuity. I presume the dimensions are the same, the main body is 15mm like the ebay one.

It's the hole that the adjuster wheel will connect to thats worrying me. I'll have a look on RS in a sec and see if there are any better pictures. Do the wiper positions matter?

Working from home, so here are the pics, I'll try to describe how to connects together (well, how I think it connects together):



is all I have. The middle part is sat upside down in this pic



The underside of it all

This part drops into the main part in this orientation. I presume I am missing a park that goes inbetween these bits to provide the connection? Bridging the 2 contacts on the housing did do something to the motor speed



The 25k mark



Measurements





Collector and restorer of vintage vacuums, Dyson Appreciator! Come and see my blog, where I am uploading all my mountains of brochures, manuals and other vacuum cleaner paperwork, and also my youtube channel @beko1987!

Offline Tech12

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Re: Potentiometer Questions
« Reply #4 on: September 30, 2015, 04:22:24 PM »
Hi Sam: OK it's broken, but just for you to know in future: Across the 2 outer terminals on the pot you should have resistance for a good pot, in this case it would show 25K. From either of the outer terminals to the centre you would have a varying resistance from 0 ohms to 25K ohms on your pot as you adjust it. You also need to make sure that the change in resistance is smooth & not jumping about, either an Analogue meter or  Digital with bar graph is best for checking.
Repairs to All makes of Small Commercial & Domestic appliance. Power tool repair.
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Offline beko1987

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Re: Potentiometer Questions
« Reply #5 on: September 30, 2015, 07:03:32 PM »
Ah I dont have access to that sort of equipment. Before it fell off the PCB I could possibly have checked the reistance, but cant now.

I did find these though

http://www.rapidonline.com/Electronic-Components/Piher-PT15NV-15mm-0-25W-Trimming-Potentiometer-Horizontal-Mount-Shaft-Adjust-528816

but, what R value would I need/would be safe? What does the R value (the first number on each title) mean? It has to adjust a 1000w motor, the 1400w boost only happens when you press the boost button, the speed adjuster only goes up to 1000.

Will be 9 delivered for 10 too, may have to wait until payday, will be taking the mickey with my buying if I get yet another thing, just spent 10 on a Hooverette...

But that gives me plenty of time to buy the correct part!
Collector and restorer of vintage vacuums, Dyson Appreciator! Come and see my blog, where I am uploading all my mountains of brochures, manuals and other vacuum cleaner paperwork, and also my youtube channel @beko1987!

Offline Tech12

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Re: Potentiometer Questions
« Reply #6 on: September 30, 2015, 07:35:58 PM »
Hi buddy: If you look, they show a 25K pot on the list. But are'nt they the same pots shown on eBay ?. You don't need a pack of 10 do you ? So the eBay listing would be better for you 1 for that PCB & 1spare.
You can test a pot with a standard Digital meter, it's just much easier to see any glitches in action with an analogue meter or Bargraph.
Repairs to All makes of Small Commercial & Domestic appliance. Power tool repair.
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Offline beko1987

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Re: Potentiometer Questions
« Reply #7 on: September 30, 2015, 07:38:42 PM »
That is true,  but the ebay listing inspires me with no confidence that I will get the right size hole for my shank (oo-er).  At least the site above lists multiple types,  rather than a picture with the important bit blurred out...
Collector and restorer of vintage vacuums, Dyson Appreciator! Come and see my blog, where I am uploading all my mountains of brochures, manuals and other vacuum cleaner paperwork, and also my youtube channel @beko1987!


Offline Tech12

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Re: Potentiometer Questions
« Reply #8 on: September 30, 2015, 07:42:53 PM »
It's your choice mate but I wouldn't be paying 9.00 for pots I may never use again. Takes all the fun and profit out of a repair, don't your local Maplin sell them ?. Or maybe a local electronics repair shop ?.
Repairs to All makes of Small Commercial & Domestic appliance. Power tool repair.
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Offline Tech12

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Re: Potentiometer Questions
« Reply #9 on: September 30, 2015, 07:48:17 PM »
On the eBay listing download, for the Horizontal mount & Vertical adjust pots they're shown with a straight adjustment slot.
Repairs to All makes of Small Commercial & Domestic appliance. Power tool repair.
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Offline beko1987

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Re: Potentiometer Questions
« Reply #10 on: September 30, 2015, 08:26:09 PM »
Plus,  ive just noticed the model number is the same on the ebay listing,  should be grounds enough to moan if they send me a pt10-lv instead...

You may have a point tech...
Collector and restorer of vintage vacuums, Dyson Appreciator! Come and see my blog, where I am uploading all my mountains of brochures, manuals and other vacuum cleaner paperwork, and also my youtube channel @beko1987!

Offline Tech12

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Re: Potentiometer Questions
« Reply #11 on: September 30, 2015, 08:47:04 PM »
I should be working on commission, saving you all this money Lol.
Repairs to All makes of Small Commercial & Domestic appliance. Power tool repair.
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Offline beko1987

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Re: Potentiometer Questions
« Reply #12 on: September 30, 2015, 10:53:56 PM »
Youd be up to about 12 now...
Collector and restorer of vintage vacuums, Dyson Appreciator! Come and see my blog, where I am uploading all my mountains of brochures, manuals and other vacuum cleaner paperwork, and also my youtube channel @beko1987!

Offline Tech12

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Re: Potentiometer Questions
« Reply #13 on: September 30, 2015, 10:58:04 PM »
Repairs to All makes of Small Commercial & Domestic appliance. Power tool repair.
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Offline beko1987

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Re: Potentiometer Questions
« Reply #14 on: September 30, 2015, 11:11:26 PM »
I bought the ebay ones, almost tempted to pop a plug on my soldering iron (I pinched it years ago), pinch a bit of solder from my stepdad and have a crack myself...
Collector and restorer of vintage vacuums, Dyson Appreciator! Come and see my blog, where I am uploading all my mountains of brochures, manuals and other vacuum cleaner paperwork, and also my youtube channel @beko1987!

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