Keithley DMM7510 Rubber Brick - Page 1
Forum section: electronics / testgear

author: jjoonathan
author_rank: Frequent Contributor
timestamp: October 02, 2022, 09:32:32 pm
content: I hope this doesn't catch on. I was repairing a DMM7510 with stuck buttons (in the sense of "they don't register presses without extreme pressure") and discovered that the front panel construction didn't have a removable, washable blister pad. Instead it had a "rubber brick" glued to a circuit board, which was a major PITA to remove!https://youtu.be/PLhyBDveVxI?t=288Is this a Keithley special or is it a new (terrible) trend that people have seen elsewhere?

author: Hydron
author_rank: Super Contributor
timestamp: October 02, 2022, 10:36:13 pm
content: Never seen that before!The DMM6500 (which came out after the 7510) uses normal buttons like everything else does. Still not the best button feel, but good enough and much easier to fix.

author: jjoonathan
author_rank: Frequent Contributor
timestamp: October 02, 2022, 11:27:46 pm
content: I'm glad to hear that! It sounds like maybe the experiment didn't pay off and we are safe from iPhone-style assembly processes for a little bit longer

author: HighVoltage
author_rank: Super Contributor
timestamp: October 03, 2022, 09:10:27 am
content: I have never seen that either.My two DMM7510 are still working ok but sometimes I notice I have to press a little harder on the buttons.What was the failure?Did you just have to clean the pads?

author: MegaVolt
author_rank: Frequent Contributor
timestamp: October 03, 2022, 10:04:28 am
content: Thank you for the video.I will seriously think whether I need to repair these buttonsThey are already almost dead.Maybe I need a remote control...Terrible design

author: jjoonathan
author_rank: Frequent Contributor
timestamp: October 03, 2022, 12:17:30 pm
content: I think the failure had to do with adhesive evaporating and condensing on the conductive pads / boards. Cleaning them with isopropyl alcohol cleared up the problem and it hasn't returned.I already had to push quite hard when I first purchased the DMM, but the situation got worse until I had to grasp the DMM body to press hard enough. After some time I had to grasp and keep the button depressed for almost a second before it would register.The virtual front panel is pretty nice, but still, tough choice. Whatever you choose, best of luck MegaVolt.

author: arcitech
author_rank: Regular Contributor
timestamp: October 04, 2022, 01:42:01 am
content: Damn, I’ll bet if that was purchased in the past couple months it was one that I was eyeballing. Did the seller disclose this “difficult to use” characteristic in the listing?This info is certainly going to keep my sights set on other 7.5d meters (my growing pile of 6.5s, a lone DMM6500 and its scan card chief among them, keep me happy for now).Guess I no longer need to get insights into whether the 7510 is much louder than the 6500…Thanks a ton for sharing.

author: HighVoltage
author_rank: Super Contributor
timestamp: October 04, 2022, 07:45:02 am
content: Quote from: jjoonathan on October 03, 2022, 12:17:30 pmThanks for this info, that could become very useful, when I need to fix my DMM7510The adhesive pad is between two surfaces squeezed.Its hard to imagine that the glue vapor could cause this.Maybe its just an oxidation over time on the contacts?Anyhow, your repair is very valuable!I think eventually all DMM7510 will suffer from this problem.

author: jjoonathan
author_rank: Frequent Contributor
timestamp: October 04, 2022, 03:07:36 pm
content: Maybe, but the board had good ENIG with no visible signs of corrosion. Perhaps the conductive polymer pads degraded? I still like my evaporation/condensation theory on account of it involving the one major thing Keithley did differently from everyone else (adhesive). They had an industry standard proven setup and they changed one thing, so naturally I suspect it. Diffusion through the adhesive region would be slow on normal timescales, yes, but this happened over years, and having some goopy organic residue covering the contacts seems like it would create the observed symptoms. This is all just speculation, though. What I know is that wiping and scrubbing both sides with IPA fixed the problem.@arcitech, no, I bought this DMM7510 a few years back. The seller didn't disclose the exact problem, but they marked it For Parts/Repair, so it could have been worse

author: HighVoltage
author_rank: Super Contributor
timestamp: October 04, 2022, 04:03:31 pm
content: Quote from: jjoonathan on October 04, 2022, 03:07:36 pmThat's the most important part and thank you for this discovery.

author: aronake
author_rank: Frequent Contributor
timestamp: June 07, 2025, 06:53:54 pm
content: As I commented to the youtube video Keithley 2450 SMU has the same terrible "rubber-brick" design.They keys on mine was pretty bad. So got the rubber brick off the front PCB, luckily with no damage. jjoonathan's video was helpful here.Cleaned PCB and conductive pads with IPA. Put together. It worked better but not great.There are lots of different methods recomended on youtube how to repair rubber button remote controls. I used the method using a pencil, grinding of some graphite and "painted" the conductive rubber pads with graphite until they got shiny. Put together and now it works quite well. My new double sided tape is a bit more strategically places than the original glue/tape, so pretty easy to take a part again if needed, but still holds together.

author: coppercone2
author_rank: Super Contributor
timestamp: June 08, 2025, 08:38:24 pm
content: I noticed the engineers at work that like 'potting compounds' are not the type of people you would like to build the equipment you need to service. It's always the guy that is working with the 'police' that are trying to 'restrict' the equipment for sales related reasonsI thought it was cool at first but it works exactly how you think it might not work out because people are supposed to be 'nice'.To the point where they want the spec the wrong compound for 'security' reasons rather then to increase reliability (i.e. a hard one that decreases reliability).Thankfully smarter people often prevail, that hold the end buyer accountable to a 'contract' (most of the money) rather then trying to make sure some dregs in the far future might not benefit.... the analysis seems to show that worrying about that far future is a waste of money and decreases your reputation AND options that you might think of later (and deals). Its 'theater' like with masks and capes.And its hilarious when a big batch of shit can't be repaired or retrofitted or retested or repurposed or modified or studied (electrical or mechanical or other analysis that requires substantial sample size for a field problem) because of a ECO or other discovery or complaint or request because of compound or glue. And when they can't get parts or materials or money or people to build more... then someone asks "well why is thisshiton here.....?" when someone ships it to someone for some work ANYWAY. The little meeting might be smiles and understanding but later when they rework the budget a few times and think about why the spec is as it is and can't make it work it starts gettingsinisterat the little informal meetings and interactions.......also related to lock out of processors and keys and such. Its like a 15 year old loosing keys to his dads PorscheBe wary of buying security you don't need....

author: aronake
author_rank: Frequent Contributor
timestamp: June 12, 2025, 02:20:34 pm
content: After my first round of detaching the "rubber brick" from the PCB, cleaing the contact pads and "painting" them with graphite, the buttons turned acceptable.I wanted to take it to next level so got below kind of conductive mesh pads installed on top of the conductive rubber tips.It then went from acceptable to pretty good. Better than on brand new Keithley gear with same kind of buttons. So highly recommended. Still not great though as the general feel of these rubber buttons are quite so so. Keysight/Agilent, despite also using rubber buttons are quite a bit better. Then of course we have Japanese gear buttons which is a completely different level of feel and functionality. Like the Yokogawa rubber keys, or even better ADCMT plastic keys.https://detail.tmall.com/item.htm?_u=c2lgsmegde31&id=872581554569