Fluke 70 series (old square type) switch - Page 1
Forum section: electronics / testgear

author: Excavatoree
author_rank: Frequent Contributor
timestamp: June 28, 2013, 01:11:22 am
content: I purchased a Fluke meter off of a well known auction site that was missing it's knob. When the knob of the 70 series meters is removed, it's easy to damage the switch, especially by trying to turn the rotor by hand. (or using whatever is handy.)I hoped for the best, but I bid low enough to prepare for the worst, and that's what I got - the switch was mangled. I was able to rob a switch from a beyond repair 70 series and it's doing fine.I was just wondering, has anyone ever had any success straightening these switch contacts back out? I've never had any luck - the things always get "flaky" and just become unreliable. Also, I thought I'd show everyone the most mangled 70 switch I've ever seen.I've seen the inner switch of the 27 type (includes 8025A, 8025B and 25) get mangled when, during diss-assembly or re-assembly, the two switches get shifted relative to each other. It's always the inner one that get's mangled. I've replaced two, and you have to take the outer one off to get to it.

author: ModemHead
author_rank: Frequent Contributor
timestamp: June 28, 2013, 01:28:50 am
content: I have a 73-III that looked like someone had gotten really clumsy while changing the battery or something and mangled several of the contacts. None of the contacts were actually broken, just kind of bent off to the side. Using needle-nose pliers, dental picks and patience, I got them all lined back up again, and the meter is still working fine. I was expecting the metal to be really brittle and springy, but it was surprisingly ductile.Of course the one you have pictured is beyond repair!

author: retiredcaps
author_rank: Super Contributor
timestamp: June 28, 2013, 04:29:47 am
content: Quote from: ModemHead on June 28, 2013, 01:28:50 amNo possibility of a Molex connector like style fix ala Beckman 3020?

author: ModemHead
author_rank: Frequent Contributor
timestamp: June 28, 2013, 11:32:31 am
content: Quote from: retiredcaps on June 28, 2013, 04:29:47 amSometimes the trashman wins.

author: Excavatoree
author_rank: Frequent Contributor
timestamp: June 28, 2013, 12:13:35 pm
content: I figured if anyone had ever done it, Modemhead would have. It's good to know that someone else concurs that the switch was too far gone. Plus, it was horribly dirty.I'm not familiar with the "Molex connector like style fix." Did I miss a thread or something?

author: ModemHead
author_rank: Frequent Contributor
timestamp: June 28, 2013, 07:48:41 pm
content: Quote from: Excavatoree on June 28, 2013, 12:13:35 pmIt'shardcore repair pornwith tin snips and rotary tools and solder.

author: lowimpedance
author_rank: Super Contributor
timestamp: June 29, 2013, 05:15:38 am
content: Quote from: ModemHead on June 28, 2013, 07:48:41 pmSerious effort there, glad it paid off. Sometimes you just have to go that extra mile to save some 'landfill'.As to the fluke well the one in the photo is toast but the contacts look like the ones in the old 'oak ' switch wafers i have at work.If you only need to replace one or two 'contact fingers' you could try to find a suitable wafer with about the right finger dimensions (old junk gear perhaps, not necessarily another FLUKE mm), and drill the rivet out and then use a small screw and nut, (10BA etc), to attach it to the FLUKE wafer (after removing the stuffer finger on the FLUKE of course).I have done just this procedure for a switch in an old Kenwood amplifier many years ago and it still working.