Destruction and Inside of MultiTurn 200 Ohm Bonens (Bourns Immitation) Trimpot - Page 1
Forum section: electronics / projects

author: Mechatrommer
author_rank: Super Contributor
timestamp: July 06, 2016, 01:35:47 pm
content: curious...when compared to original Bourns...http://www.robotroom.com/Trimpots-2.html

author: calexanian
author_rank: Super Contributor
timestamp: July 06, 2016, 10:40:46 pm
content: That is actually not too bad. I was expecting worse!

author: Vgkid
author_rank: Super Contributor
timestamp: July 06, 2016, 10:51:40 pm
content: Thanks for pulling one apart. Actually not bad.

author: bitseeker
author_rank: Super Contributor
timestamp: July 07, 2016, 04:33:01 am
content: Neat. The brush is definitely wimpier.

author: CJay
author_rank: Super Contributor
timestamp: July 07, 2016, 08:42:27 am
content: Nice pics and doesn't look too bad at all.Did you tear it apart because it failed (if so what was the failure) or just 'because'?

author: Mechatrommer
author_rank: Super Contributor
timestamp: July 07, 2016, 11:14:47 am
content: Quote from: CJay on July 07, 2016, 08:42:27 amno. just for fun, i still have some stock for that 200 ohm trimpot and i find it the least used part. and i was curious on inductive effect of it. i guess not suitable for ghz range of application, similar to original Bourns since they are the same geometry construction. but on some of the other Bonens immitation that already in a circuit, i detected some discontinuity at some place usually set during operation, but not so serious for me to take it apart so far, a slight turn will get it back inline. i cant 100% blame on the components since its maybe my design is flawed, i havent analyze its heat dissipation spec.

author: Melt-O-Tronic
author_rank: Frequent Contributor
timestamp: July 07, 2016, 03:44:11 pm
content: This is nifty. I always wondered what happens internally when you hit the limit of travel. Now I can see that, at least for this style, continuing to turn at the limit won't cause damage. Thanks!

author: Fungus
author_rank: Super Contributor
timestamp: July 07, 2016, 04:01:25 pm
content: Quote from: Melt-O-Tronic on July 07, 2016, 03:44:11 pmI want to know how it comes back if you go past the end then start turning it backwards.Doesn't that disconnect the gears?

author: Mechatrommer
author_rank: Super Contributor
timestamp: July 07, 2016, 05:24:43 pm
content: Quote from: Fungus on July 07, 2016, 04:01:25 pmon the working unit, clicking sound can be heard while attempting to go past beyond the end indicates some sort of spring action that reverse the last teeth of the gear back inline, but i cant reproduce it on the teared unit. luckily i'm not inclined to know how it function mechanically, all i know is its working.

author: metrologist
author_rank: Super Contributor
timestamp: July 07, 2016, 07:36:12 pm
content: I suspect the wiper is in spring contact with the end-point and pushes the gear drive together.

author: LabSpokane
author_rank: Super Contributor
timestamp: July 07, 2016, 08:25:36 pm
content: I bought a grab bag of those to have for prototyping and they work OK, particularly for the price. I'd run the Bourns for production.

author: mikerj
author_rank: Super Contributor
timestamp: July 07, 2016, 10:26:33 pm
content: I'm guessing this was a pretty heavily used device? There seems a be a lot of brush material embedded into the resistive track, and the brushes themselves look a little worn.

author: Mechatrommer
author_rank: Super Contributor
timestamp: July 08, 2016, 12:21:51 am
content: Quote from: mikerj on July 07, 2016, 10:26:33 pmno, it only used a few times in a test circuit. most of the time ever since collecting rust. maybe that shows the low quality of the internal parts of it..

author: Fungus
author_rank: Super Contributor
timestamp: July 08, 2016, 07:39:48 am
content: Quote from: mikerj on July 07, 2016, 10:26:33 pmThat might be from the disassemble process.All the internal parts in those things are really soft so they make good contact. They're not built for daily use. Even the genuine parts are only rated for 200 turns.