Need help designing a couple of simple circuits

[zeiram]

Hello I am a newbie here, and while I can fix circuit boards and various electronics, I need some help. I am trying to replace an electromechanical circuit in an old game with some electronic circuits to do the same thing. The parts are no longer available and to modify the existing parts is somewhat problematic.

Part 1 I need to switch a 50V AC circuit on and off every second. This runs continuously while the machine is on. I do have a source of 110v in the machine to power it as well as the 50V AC.

Part 2 A circuit to "fire" a switch on twice within a 1/2 a second. This will be activated using a relay and will also be using the existing 50V AC.

Hopefully someone out there can help me. I really appreciate it! Thanks Chris

[KMoffett]

Part 1 I need to switch a 50V AC circuit on and off every second. This runs continuously while the machine is on. I do have a source of 110v in the machine to power it as well as the 50V AC.

Is this on for 1/2 second and off for 1/2 second, or on for 1 second and off for 1 second? Or some other on/off ratio?

Part 2 A circuit to "fire" a switch on twice within a 1/2 a second. This will be activated using a relay and will also be using the existing 50V AC.

"activated using a relay"...is the relay contact closed for a period shorter or longer than the 1/2 second two pulse firing?

Ken

[zeiram]

Hey Ken,

Part 1 It is for the 1/2 second on 1/2 second off.

Part 2 Well the relay pulls in a little pin that lets the score disk turn and then resets when the score motor turns. (Sounds complicated but that is how the old electromechanical gun games work) SO I would have to slightly longer.

Does that help?

Thanks
Chris

[zeiram]

Hello Ken,

Part 1... it would be for 1/2 second on and 1/2 second off.

Part 2... Well I am trying to mimic what the machine does. It activated a solinoid that pulls a small gate, that lets a disc turn of 1/3 of a second that makes contact with the switch twice in that 1/3 of a second. That scores 50 points twice. It is for an electromechanical gun game from the 50's.

Thanks for your help!
Chris

[KMoffett]

For the 1/2sec on-1/2sec off circuit, I would use a 120VAC/12VDC wall wart to power a LM555 1-second astable oscillator driving a 12dcv relay that switches the 50VAC on and off. Depending on how much current that clocked 50vac supply needs to switch will depend on how long it lasts.
Another approach is a 60 RPM timing motor with a cam wheel that switch a roller "Microswitch" on and off.
To get rid of the life expectancy problem with the electromechanical relay or switch, a solid state solution would require more knowledge of the switch loads.

I'll think over the other problem.

Ken

[KMoffett]

Part 2... Well I am trying to mimic what the machine does. It activated a solinoid that pulls a small gate, that lets a disc turn of 1/3 of a second that makes contact with the switch twice in that 1/3 of a second. That scores 50 points twice. It is for an electromechanical gun game from the 50's.

So you want to replace this switch with a relay that is driven by a circuit, when triggered, will pulse the relay twice (~100mS each) in ~333mS?

Ken

[KMoffett]

After a little thought (in spare time) : two LM556 (dual 555s) ICs.
#0: 12VDC wall wart
#1: 1/2 LM556: an astable oscillator with a one second period that switches a small relay to give a 50VAC 1/2sec ON and 1/2sec OFF.
#2: 1/2 LM556, a LM556, and a two-diode-OR gate: 3 monostables sequentially connected with ~300ms periods. The outputs of the first and third monostables are diode-OR'ed to a small relay that switches the 50VAC (normally OFF) ON(300mS)-OFF(300mS)-ON(300mS)-OFF

Ken