Trimmer tools for "through the hole" trimming of pcb trimming pots - Page 1
Forum section: electronics / testgear

author: Specmaster
author_rank: Super Contributor
timestamp: November 03, 2017, 01:40:00 pm
content: What trimming tools do you use for trimming the small 6mm type of trimming pots on circuit boards like oscilloscopes etc. that have access through holes drilled in the pcb? I have a few trimming tools but none of them will either fit through the holes or if they do, they don't have the reach or the right tip to fit the pot!The trimming pots on the boards I need to adjust have either small crosses or a slot that I need to fit into and rotate?I attach photo of the ones I have which I think are the CK Tools ones and the 2 on the right will go through the holes but have small square tips on them

author: bd139
author_rank: Super Contributor
timestamp: November 03, 2017, 01:53:14 pm
content: I use a bog standard screwdriverhttps://www.amazon.co.uk/dp/B009ODV0PI/Usually from the above set. I got a set on an Amazon sale day for £19 I think it was.Edit: also one of these for capacitors:http://uk.rs-online.com/web/p/trimmer-resistor-mount-adaptors/7432479/

author: Specmaster
author_rank: Super Contributor
timestamp: November 03, 2017, 02:08:55 pm
content: I have a set similar to those but they won't pass through the holes as I have to access the rear of the trimmer. Its on the Goldstar CRO and all the trimmers are mounted on the component sides and then they go and flip the boards so the only access is the solder side with insufficient space to access from the other sidePoles apart from the construction of the HP 1740A where it was arranged for repair and adjustment

author: bd139
author_rank: Super Contributor
timestamp: November 03, 2017, 02:21:19 pm
content: Thurlby power supplies are the same. The trimmers are on the front panel. You have to get your hand inside it and about an inch away from uninsulated mains taps on the transformer before you can turn the pots. I usually put some cardboard over that first or bzzt!

author: Specmaster
author_rank: Super Contributor
timestamp: November 03, 2017, 02:47:06 pm
content: Direct access is not possible on this, there is only 50mm clearance between components on the 2 pcb's and then some of the trimmers are 800mm in from the edge. I need something like a screwdriver with 1.5mm dia shaft, stepped down to 1mm for 11mm length with a 1mm flat blade to reach

author: bd139
author_rank: Super Contributor
timestamp: November 03, 2017, 02:51:08 pm
content: That's a bit of a bugger. I'd hit poundland then get the angle grinder out and MacGuyver something

author: Specmaster
author_rank: Super Contributor
timestamp: November 03, 2017, 02:54:31 pm
content: There has to be something suitable because they have to set them up in the factory and calibration houses

author: Specmaster
author_rank: Super Contributor
timestamp: November 03, 2017, 02:58:22 pm
content: Quote from: bd139 on November 03, 2017, 01:53:14 pmYes I look at those, I have similar ones by Proskit, but they don't fit. Bourns do one with a blade that would fit, the H-92-1 but their data sheets total omit the diameter of their tools from the data sheet

author: bd139
author_rank: Super Contributor
timestamp: November 03, 2017, 02:59:09 pm
content: If it looks like that one it's about 3.5mm at the tip.

author: Specmaster
author_rank: Super Contributor
timestamp: November 03, 2017, 03:10:57 pm
content: I have to go shopping in a minute or two so I'll nip into Maplins and see if the have anything that will fit. I have some fine jewelers screwdrivers that would fit but their all metal and I'm working on live circuits.

author: bd139
author_rank: Super Contributor
timestamp: November 03, 2017, 03:19:02 pm
content: Insulation tape FTW

author: Specmaster
author_rank: Super Contributor
timestamp: November 03, 2017, 03:23:51 pm
content: Problem solved, I remembered I had this problem before and I found a set of drivers that fitted, problem is though that my son who builds lots of models burrowed them and kept them in his drawer. I just fished them out and presto they fit like a charm

author: Cerebus
author_rank: Super Contributor
timestamp: November 03, 2017, 04:54:27 pm
content: Quote from: Specmaster on November 03, 2017, 03:10:57 pmHeatshrink!

author: bd139
author_rank: Super Contributor
timestamp: November 03, 2017, 04:57:12 pm
content: Quote from: Specmaster on November 03, 2017, 03:23:51 pmI actually had a set of them before I got the Wera ones. They're quite good.

author: LaurentR
author_rank: Frequent Contributor
timestamp: November 03, 2017, 05:15:28 pm
content: Find any mini-screwdriver that fits and cut the shaft to whatever length you can fit and put some knob (even just a pile of electrical tape) on the cut end.Another option is to get a set of mini-screwdriver tips and use the tip directly.To stay in the theme of high-quality German screwdriver, you can get a set of Wiha like this one:https://www.wihatools.com/sys-4-esd-safe-micro-bit-26-piece-set

author: SeanB
author_rank: Super Contributor
timestamp: November 03, 2017, 05:49:20 pm
content: At Poundland get a nice set of plastic crochet needles and do a bit of work with a file to get the end screwdriver shaped, and use it as an adjuster.

author: Neomys Sapiens
author_rank: Super Contributor
timestamp: November 03, 2017, 06:28:17 pm
content: Bernstein has all the adjustment tools that you'll ever need. They make a type with bronze alloy blades set into very slim shafts which should do the task. For example, type 1-301.http://www.bernstein-werkzeuge.de/

author: Specmaster
author_rank: Super Contributor
timestamp: November 06, 2017, 10:56:19 pm
content: Quote from: SeanB on November 03, 2017, 05:49:20 pmHaha, I tried that, all they had was metal knitting needles, but its a good tip anyway, so I'll be keeping my eyes open for them. If all else fails we do have dedicated crafts shops but their prices will be sky high but first I'll try all the pound based shops on a regular basis as their stocks are constantly changing and also a couple plastic needles would make excellent prodders as well.

author: macboy
author_rank: Super Contributor
timestamp: November 07, 2017, 01:39:47 pm
content: Search ebay (etc.) for "ceramic screwdriver". I bought a set of various slot/flat and cross/philips sizes. They are non-conductive and equally important, non-inductive. The ceramic's surface also provides good grip. Be careful, especially if you have concrete floors (my lab is in my basement) as they will not survive a fall. And don't be tempted to drive screws with them, they are trim tools only.

author: macboy
author_rank: Super Contributor
timestamp: November 07, 2017, 01:59:36 pm
content: Quote from: bd139 on November 03, 2017, 02:21:19 pmThe trimmers for adjusting the volt and amp meters on a Keysight E3620A power supply are less than an inch directly above exposed terminals of the front panel mains power switch. I have also used the cardboard trick. Imagine dropping an all-metal jeweler's screwdriver onto those things.

author: bd139
author_rank: Super Contributor
timestamp: November 07, 2017, 03:06:00 pm
content: Yeah and right behind the RIFA X2 flame thrower too!I actually like the E36xx supplies.

author: Cerebus
author_rank: Super Contributor
timestamp: November 07, 2017, 03:09:31 pm
content: Quote from: macboy on November 07, 2017, 01:39:47 pmGood call! Knowing the exact search term can make the difference on ebay between instantly finding what you want and 2 hours fruitless searching.

author: Specmaster
author_rank: Super Contributor
timestamp: November 07, 2017, 03:37:56 pm
content: Quote from: macboy on November 07, 2017, 01:39:47 pmAlready looking for some of them as well as the plastic needles of either the crochet or knitting varieties as they also make excellent prodders for tracking bat connections etc.Sent from my SM-J510FN using Tapatalk