Old style Television on/off switch. - Page 1
Forum section: electronics / beginners

author: asterone
author_rank: Contributor
timestamp: March 15, 2020, 06:12:39 am
content: Hi, Ive got the shell of an old 60's TV that I would like to restore, all internal electronics are long-gone so i'm hoping to be able to fit a more modern CRT's internals inside.Ive run into a snag that I can't seem to find a decent solution to....So I'm wanting to keep the functionality of the old TV's switches, but the on/off switch is a little tricky as it has a separate button for on and another one for off. When set is turned on the 'on' button is down and the 'off' button is up. When switching the set off the 'off' button gets pushed down and the 'on' button gets pushed up or 'out' (see attachments)The newer CRT has a more modern latching switch, a push in for on and another push to release the switch, turning it off. (attachment switch2)I just can't see anyway mechanical way to have the old on/off buttons properly actuate the newer mechanism.Perhaps it would be easier to replace the newer crt's on/off switch mechanism with another one that could be actuated by the old buttons easier? What would I be looking for? Something like this that has separate on & off?Perhaps all i need is the right search term to find a switch with separate on and off buttons...Sorry if it's hard to decipher what i'm trying to do, it's a little bit hard to describe!

author: james_s
author_rank: Super Contributor
timestamp: March 15, 2020, 07:04:39 am
content: Is the original switch present and functional? If so then this should be pretty trivial, you want something called a one-shot, or mono-stable multivibrator, something that will turn a change of state on the input into a single pulse of a consistent length. From a hardware standpoint the easiest and most versatile way to do this is to use a cheap 8 pin microcontroller.It's a shame the original electronics are gone, that would be a neat TV restored to original condition.

author: ludzinc
author_rank: Unknown
timestamp: March 15, 2020, 07:08:49 am
content: Or use two momentary switches, with a latching relay?

author: Nusa
author_rank: Super Contributor
timestamp: March 15, 2020, 07:41:21 am
content: I'm sure the original on-off solution was mechanical, operating a single-pole switch of some sort.I don't know the distance between buttons in your pictures since there's no scale, but wouldn't surprise me if a rocker-style wall switch could be adapted to the job, if you can figure out how to mount it.

author: asterone
author_rank: Contributor
timestamp: March 15, 2020, 08:18:44 am
content: Quote from: ludzinc on March 15, 2020, 07:08:49 amThis sounds pretty straight forward, ill give it a go.

author: asterone
author_rank: Contributor
timestamp: March 15, 2020, 08:21:40 am
content: Quote from: Nusa on March 15, 2020, 07:41:21 amYep, crossed my mind, distance is 45mm between buttons, I could make an interface between buttons and rocker i guess...

author: asterone
author_rank: Contributor
timestamp: March 15, 2020, 08:38:19 am
content: Quote from: james_s on March 15, 2020, 07:04:39 amYes, the retro TV restorers would be fuming that the internals were wasted, but coming from a non-EE background, I had no ability to restore this to original. It has been educational however taking apart the more more modern CRT and learning the basics, studying it's schematic and adhering to the safety precautions associated with the high voltage FBT!!

author: AVGresponding
author_rank: Super Contributor
timestamp: March 15, 2020, 10:44:41 am
content: What would work is something like older range/channel selector switches that are mechanically ganged to release other switches when you press a new one.I couldn't find any new with a quick 5 minute search, but they were commonly used on tvs, amps, washing machines etc in the 1970s and 1980s.Might be worth looking for some parts only stuff on ebay/craigslist etc that has these fitted.They are essentially modular, you can usually cut down the mechanical section if you need to remove a couple of switches to fit your design.

author: Raj
author_rank: Frequent Contributor
timestamp: March 17, 2020, 02:54:46 pm
content: Just get a latching switch,suitable for the current you need and use a 3d printer to print whatever kind of shell you want, over it.Don't have a printer? some companies ship the thing you want them to print,to you.If you want a solid state method-had it been DC powered, I would have recommended using an SCR. But since it isn't, i'd recommend relay logic.If you're an advanced user, you can get a mains to 5v chip, use it to power a micro controller that remains on forever (until it's unplugged), andgive button's input to it and let it switch a SSR

author: Raj
author_rank: Frequent Contributor
timestamp: March 17, 2020, 03:04:55 pm
content: Also, it looks like that switch in the photo is still in production-https://ph.rs-online.com/web/p/push-button-switches/1239059/If you are not able to do it in the end and end up resolving to use a single "button" for ON OFF... use the other button for added functionality like back-lighting (lighting up the wall behind the tv, to reduce stress when you watch it in a dark room)