HP3466A Damage Switch - Opinion Request - Page 1
Forum section: electronics / testgear

author: rfdes
author_rank: Regular Contributor
timestamp: October 20, 2023, 04:43:54 pm
content: Hi -I am looking for some suggestions. I have a recently acquired an HP3466 multimeter that I am attempting to get up and running. As no surprise, the ganged push buttons were dirty and needed cleaning. 'Mr 5 Thumbs' managed to damaged the plunger plastic retainer flap as shown in the photos. I've been unsuccessful in finding a replacement switch and now at the point where I want to attempt to repair this the best I can. The plastic is likely polypropylene and adhesives are probably not going to work in this case. So, I was hoping someone who understands the construction of these switches might have a clever idea for implementing a patch for this retainer clip. There is a photo of the broken unit and one of the non-broken switches for comparison.Your thoughts are appreciated.ThanksJim

author: enut11
author_rank: Super Contributor
timestamp: October 21, 2023, 11:38:33 pm
content: A quick fix could be a suitable hardwood towel cut to fit the switch, perhaps painted or covered in heat-shrink. You need to find a suitable spring or make one from thin piano wire.

author: Technotronic
author_rank: Contributor
timestamp: October 22, 2023, 04:53:51 pm
content: They look alot like C&K F2UEE or F4UEE type switches. I saved some duds I replaced over the years thathave good actuators. Looks like you need a new plastic cover on the black one. Hard to tell how many rows of contactsit has but I suppose you could carefully remove the plastic cover on a dud, cut it in half and transplant if you have the patience.If you want a couple of my duds you are welcome to them....actually one of those covers is already separated.

author: rfdes
author_rank: Regular Contributor
timestamp: October 23, 2023, 12:31:13 am
content: Quote from: Technotronic on October 22, 2023, 04:53:51 pmThanks for your reply. The second photo looks just like the top of my damaged unit. My unit is a 6PDT unit and your idea of cutting it down and splicing in yours sounds doable. How did you remove the top from the switch in your second photo? They look like they probably slide over the solder lugs and latch in place. Your second photo appears like you may have needed to use some heat to release the latch. I believe I would like to take you up on your offer for the duds.Thanks again.Jim

author: Technotronic
author_rank: Contributor
timestamp: October 23, 2023, 12:40:31 pm
content: JimYes I think when I was unsoldering these the heat fouled them up mostly, melting the plastic frames,and loosening up the contacts in the housing.I think you can remove that upper cover carefully with a heat gun on it and a jewlers screwdriver gently prying it off...itdidnt take much for that cover to come off in the pic. I am sending you that cover as well.Steve

author: rfdes
author_rank: Regular Contributor
timestamp: October 23, 2023, 06:58:02 pm
content: Steve -I removed my switch this morning successfully with no apparent heat damage. So when I receive your parts, I am confident that I will be successful in repairing the damage switch.Oddly, just a bit ago I did some Google poking and came across a forum thread from 2015 (Dutch site) where the OP was needing to replace one of these switches from the same piece of HP equipment. It turns out that he was successful using one of the C&K F2UEE style switches as you called out. I did some physical measurements prior to finding this forum thread and the dimensions indeed agree. So, if my modified switch turns out to be unsuccessful, I know that I can purchase a new switch and replace it altogether.Here is a link to the forum thread if anyone is interested.https://www.circuitsonline.net/forum/view/125815Thanks for the helpJim

author: Technotronic
author_rank: Contributor
timestamp: October 23, 2023, 10:36:07 pm
content: Welcome Jim, sounds like you have it under control.Yes mechanical switches in general seem to be going extinct for ss type circuitsso saving what seems to be junk otherwise pays sometimes.I once did a ganged array like that in a Sony 1980's amp where they were all badlyoxidized inside and causing weird symptoms.I immersed the entire gang in several inches of plain vinegar, actuated them all many cycles,let them soak 20 mins and an large amount of crud surfaced to the top. I followed up with water,then some deoxit to protect them and it came out fantastic.With the cost of contact cleaner thru the roof these days, vinegar makes a good alternative.

author: rfdes
author_rank: Regular Contributor
timestamp: October 31, 2023, 03:29:14 pm
content: Hi Steve -I received your dud switches and was 100% successful in the repairing my damaged switch. As mentioned, I was able to cut out the broken switch section and insert the proper section of one of your switches (with a little trimming). It came out nicely.Thanks gain for the help, I'm back in business.Jim

author: Technotronic
author_rank: Contributor
timestamp: November 01, 2023, 08:26:24 pm
content: Well done Jim.Glad the operation went as planned !