GW Instek GPE-4323: Anyone tried replacing the pots? - Page 1
Forum section: electronics / testgear

author: IDEngineer
author_rank: Super Contributor
timestamp: May 06, 2019, 03:08:52 pm
content: I bought one of these units new a while back and like it quite a bit. Nice linear supply, reasonably quiet, decent voltage and current capacities, etc. My two complaints are the arrangement of the output connectors (CH4 - CH1 - CH2 - CH3, wanna guess how many times I accidentally connected to 4 instead of 1 or adjusted the wrong knob?) and the oversensitivity of the pots since they are single turn controlling a rather wide dynamic range.I can't fix #1, but perhaps I can swap in some 5-turn (preferred) or 10-turn panel pots instead of the singles to improve resolution. Anyone tried this yet? Are they connected via flying leads or soldered direct to a PCB? I can get their values with a DMM but before I crack it open I'm wondering if anyone has any personal experience to share, like "It's super easy" or "Don't even bother because...".Thanks!

author: HalFoster
author_rank: Frequent Contributor
timestamp: May 06, 2019, 07:47:32 pm
content: Did it a month or so back... The pots are 10K as I remember, the only thing is that they need to be low profile - Bourns makes some - don't remember the model at the moment but they can be found - they are only 3 1/2 turns, but that actually is a huge improvement over the one turns. Don't try to de-solder the side tabs at first - cut them with a pair of good side cutters and remove after main pot has been removed if you want - the new ones don't have tabs - might need to shim about 1/4 inch - once I verified the operation of mine I just shot a good blob of hot snot under them and they are rock solid.HalPS: finding the pots was the hardest part - wound up sourcing mine on e-pray about 6 months prior.

author: zzattack
author_rank: Regular Contributor
timestamp: May 06, 2019, 07:59:16 pm
content: Definitely interested in doing this on mine, ever since I changed it from 3 to 4 digit readings I always spend a ton of time getting the last digit to read 0

author: HalFoster
author_rank: Frequent Contributor
timestamp: May 07, 2019, 09:42:06 am
content: Well, keep in mind that just because it says "0" doesn't mean that it actuallyis- just not going to get that kind of accuracy from a GPE-4323. If mV or better accuracy is truly needed, pick up a nice Power Designs 2020, 5020 or similar off e-Pray. For me, the reason to change them was to be able to vary the voltage without worrying that a twitch was going to jump it up 2 V instead of 2 mV and let the magic smoke out. That's probably what you meant, but i guess that it bears repeating...Hal

author: HalFoster
author_rank: Frequent Contributor
timestamp: May 07, 2019, 09:47:17 am
content: BTW: It's the Bourns 3856 series - shaft: 1/4" diameter x 7/8" length.Hal

author: IDEngineer
author_rank: Super Contributor
timestamp: May 07, 2019, 03:50:11 pm
content: Quote from: HalFoster on May 06, 2019, 07:47:32 pmExcellent, thank you! For the benefit of those who search for and find this thread later, here's the link to the Bourns spec sheet:https://www.bourns.com/pdfs/385126.pdfQuoteBy side tabs, you mean the factory pots have those little anti-rotation through hole pins? I'm asking because the Bourns 3856 series has an anti-rotation LUG that is molded into the body, rather than a solder pin. Just trying to make sure I understand what you're describing.Thanks again!

author: HalFoster
author_rank: Frequent Contributor
timestamp: June 06, 2019, 07:18:13 pm
content: Sorry it took a bit - been away.Yes, on mine the original pot had two of the anti-rotation lugs on the sides. I don't remember the Bourns having the lug but since mine needed to be raised a bit above the board it wouldn't have been an issue either way..Hal