Bottom adjust trimmers

[armdnrdy]

I've looked around a bit but have drawn a blank.

Does anyone know of a source for trimmers that can be adjusted from the bottom (trace side) through a hole in the PCB?

[haveyouseenhim]

I couldn't find any so I used a multi turn trimmer like this.

[armdnrdy]

Thanks for the reply Mike.

I was looking at possibly using a 3386W type, bending the pins so that the adjustment is face down on the component side over the adjustment hole.

[psychedelicfish]

Jaycar sells some square piher trimpots that can be adjusted from the bottom. Have a look on their website.

[bluebunny]

These are adjustable from both sides:

   (click for bigger picture)

These particular ones are from Rapid in the UK, but they look like generic "Bourne" trimmers, so I guess would be widely available?

[digi2t]

Bro, wouldn't you be better off using something like a Piher?



Adjustable from both sides, and judging from the hole pattern, it looks to me that's what your board was configured for.

[Govmnt_Lacky]

@Dino

What hole pattern did Larry post that you are referring to?

@Larry

Although Piher-style trimmers will definitely work... they have a large footprint. I believe you will be hard pressed to find a trimpot that is adjustable on both sides AND will fit the smaller profile footprints like the 3386 Bourns types  

Do you have the room to solder the trimmers to the trace side where they will be available to you?

[digi2t]

@Dino

What hole pattern did Larry post that you are referring to?

Looking at this pic,



it just looks to me like a Piher is supposed to Beher (pardon the pun... I just couldn't help myself  ). Note the triangular pattern around the hole where the adjustment screw is. I think the third leg is supposed to go into the lower right pad, where there is nothing now.

[Govmnt_Lacky]

@Dino

I believe that pic is from Mike (haveyouseenhim)... not Larry 

Although I do prefer the Piher trimpots for their adjustability, they do tend to take up a bit more board space than the standard 3386-style Bourns.

[haveyouseenhim]

@Dino

What hole pattern did Larry post that you are referring to?

Looking at this pic,

it just looks to me like a Piher is supposed to Beher (pardon the pun... I just couldn't help myself  ). Note the triangular pattern around the hole where the adjustment screw is. I think the third leg is supposed to go into the lower right pad, where there is nothing now.

I think you are mistaken. I posted that to give Larry an idea around the problem.

[armdnrdy]

Thank you all for your posts.

It was because of one of the posts that I began looking in a certain direction and came up with something usable and reasonably priced. (I won't say which one so you all can feel special)  

The Piher N6 series. The footprint is 6.4mm X 8.7mm so I'll have to adjust the board a bit. (yes G.L. the footprint that I used is a smaller Bourns variety trimmer.

The bonus about these trimmers is that they are available at Mouser for 25 cents.

The model # is: N6-L50TOC-103

Here's a link to the PDF:

http://www.mouser.com/ds/2/325/09-N6v03-2037.pdf

The reason I decided to go with a bottom adjust type is this build has board mounted hardware and attachment to the smaller LED/LDR board which is attached to the enclosure. The components on the main board (with the trimmers) face inside the enclosure with the trace side showing when you remove the bottom cover.

It would have been a real pain to go through the adjustment procedure with the pots not accessible when you remove the cover!