Hameg Push Button Switch Alternative - Page 1
Forum section: electronics / testgear

author: julesgilson
author_rank: Newbie
timestamp: January 04, 2017, 01:01:46 pm
content: Hi. Just wondering if anyone knows a suitable replacement for the Schadow switches used in the Hameg 203-7 for many of the front end controls, including the channel 2 inversion? The contacts on mine are mashed up (since I bought it) and it is proving hard to find a switch of similar dimensions. Even something with compatible contacts would be fine.Photo attached.Many Thanks.

author: nctnico
author_rank: Super Contributor
timestamp: January 04, 2017, 01:22:57 pm
content: ALPS SPUN series switches come to mind but may not be an exact match.http://www.alps.com/prod/info/E/HTML/Switch/Push/SPUN/SPUN_list.html

author: julesgilson
author_rank: Newbie
timestamp: January 04, 2017, 01:51:10 pm
content: Thanks for the reply.I should have mentioned the pitch is 3.2mm and row spacing 3mm. The biggest issue (in finding a direct replacement) is the length of the legs - the existing switches stand about 12.5mm from PCB to centre of the actuator.

author: WackyGerman
author_rank: Regular Contributor
timestamp: January 04, 2017, 06:37:53 pm
content: Well if the length of the legs would be a problem you could extend the shorter one with solder pins . It s a little bodgy but would help to solve your problem

author: nctnico
author_rank: Super Contributor
timestamp: January 04, 2017, 06:42:32 pm
content: Quote from: WackyGerman on January 04, 2017, 06:37:53 pmI'd keep the legs of the original switch and solder the new switch on top of them.

author: WackyGerman
author_rank: Regular Contributor
timestamp: January 04, 2017, 07:04:07 pm
content: I zoomed into the picture and at a closer look it seems that the switch is already been soldered on solder pins

author: julesgilson
author_rank: Newbie
timestamp: January 04, 2017, 07:24:40 pm
content: I can cobble something together - but as most of them seem a little flakey I would like to replace all - about 12... Was just hoping someone knew of a source - being a fairly popular family of scopes.The original switches have pins tacked on the bottom - even so the legs are considerably longer than anything I have found so far.I have a bunch of C&K switches with the same footprint.Looks like I will start cobbling

author: mos6502
author_rank: Frequent Contributor
timestamp: January 05, 2017, 01:08:33 pm
content: Have you tried contact cleaner? Preferably the type that leaves no residue. Brake clean should also work in a pinch.If that fails, I would disassemble the switch and clean the contacts manually. Always preferable to keep the original parts than to hack stuff up.

author: julesgilson
author_rank: Newbie
timestamp: January 05, 2017, 02:07:24 pm
content: The contacts are just a mangled mess - would need some very special contact cleaner! I agree it would be better to restore them, which is why I was hoping for like for like or even just compatible contacts from another switch.Thanks.

author: nctnico
author_rank: Super Contributor
timestamp: January 05, 2017, 06:26:44 pm
content: Quote from: mos6502 on January 05, 2017, 01:08:33 pmContact cleaner doesn't work long term and it contains acids which will wreck the rest of the equipment. Once contacts (or potmeters) are worn the only option is to replace them because the plating which forms the contacts is gone and the underlying material (usually some copper alloy) will corrode like crazy. I've seen it many times: equipment which could have been restored if it wasn't soaked with contact cleaner which ate into everything made out of copper (including the wiring and PCBs).

author: free_electron
author_rank: Super Contributor
timestamp: January 05, 2017, 06:56:07 pm
content: itt cannon

author: mos6502
author_rank: Frequent Contributor
timestamp: January 06, 2017, 07:23:27 am
content: Quote from: nctnico on January 05, 2017, 06:26:44 pmOK, maybe you should stop using that "HCl" brand contact cleaner ...

author: nctnico
author_rank: Super Contributor
timestamp: January 06, 2017, 08:11:34 am
content: I never used contact cleaner. It is always others and I 'have' to deal with the resulting mess.

author: tautech
author_rank: Super Contributor
timestamp: January 06, 2017, 08:22:51 am
content: Quote from: free_electron on January 05, 2017, 06:56:07 pmYep.Take your pick:http://www.mouser.com/Electromechanical/Switches/_/N-5g2h?Keyword=ITT+Cannon+-+C%26K+Pushbutton+Switches&FS=True

author: julesgilson
author_rank: Newbie
timestamp: January 06, 2017, 11:59:03 am
content: Yeah I know they were made by ITT Cannon which eventually ended up as C&K. Been through the entire C&K catalogue - no matches. Not even close in physical terms. Also been through Alps, E-Switch and a few others' catalogues....None of them have A/. The height (which could be bodged with extended legs etc.) or B/. The length from legs to actuator face (which again could be bodged with extended the pushrod). I just don't like bodges.I would assume that some have the same, more or less, contacts that I could take out and use in the original switch - so was hoping someone had done that before and knew which switch to try as a donor.Thanks

author: Fraser
author_rank: Super Contributor
timestamp: January 06, 2017, 07:53:04 pm
content: I have a pile of complete HM203 scopes and a set of removed PCB's. All are available to buy for spare parts. I am located in the UK.Fraser

author: F64098
author_rank: Regular Contributor
timestamp: January 06, 2017, 08:18:23 pm
content: You should ask here:http://www.sky-messtechnik.de/They have all the old Hameg spare parts and if you're lucky, there are still some switches on stock.HTHFrank

author: n4buq
author_rank: Newbie
timestamp: August 03, 2020, 07:18:08 pm
content: I ran across this in my search for one of the small, black plastic adapters that is shown on the pic in the first post. The adapter connects a 2mm rod/shaft to the square post that protrudes from the front of the Schadow switch. Anyone have one of those for sale?Thanks,Barry