Turning on PC monitor when mains power turned on...

[Mickey Juice]

I have almost completed my cocktail mame cab, but I have one small problem I'd love to elimate.

When I first turn on the cab from the wall, I have to open up the lid and manually press the monitor button, then it goes into standby mode and is ready to use when I power up the PC (single button on the cab).

This wouldn't be a problem if I was to leave the power on all the time and have the monitor sitting in standby mode. I dont want to do this.

Has anyone had this problem and over come it?

I thought of wiring the monitor button to the cab button using a DPDT pushbutton... but there will be a problem if I shut down the computer and then restart with the button ie the monitor will then turn off while the PC is on.

I'm thinking: Wire up a circuit with a relay (similar to what people use to power on their cabs with a single button...) so when I turn on the mains power the relay triggers the monitor switch, putting it into standby mode/turning it on. The relay would only have to close the circuit momentarily. This possible?

[danny_galaga]

a relay could work. on my cab i have a relay wired normally closed so when the power comes on it opens up the circuit in question. but for a brief instant its still closed, hence it mimics being momentarily on for a brief instant. this worked for me but not for peale who used a capacitor in a similar situation (we were both getting around having to press a button to start the pc- prefering the pc to just switch on when the main cab switch is hit).

otherwise i wonder if you could just by-pass the monitor switch and hard-wire it to just be on or off? i'm sure someone else here will be able to say if that's possible or not. i'm lucky, my monitor seems to switch on and off with the main power.

[Mickey Juice]

I was going to hardwire a new switch, but i'd prefer a single start button...

I'll have to have a look around for more solutions.

[the3eyedblindman]

Why not just leave it turned on all the time, I never turn off this monitor, if power ever turns off or anything then you could just manually turn it on whenever that happened.

[Mickey Juice]

I'd like to, but I know it's not going to happen 

I had a look at some of the Dell monitors here at work and they have push buttons that can be left either on or off. Who knows why mine is a momentary on pushbutton >_> Damn gateway!

[danny_galaga]

I was going to hardwire a new switch, but i'd prefer a single start button...

I'll have to have a look around for more solutions.

well, there you go! replace the monitor switch with a relay. have the relay switched by the main cab switch. job done!

[Mickey Juice]

The main switch is just an extension of the PC on/off momentary switch, so:
* is the voltage high enough to trip the relay?

[danny_galaga]

The main switch is just an extension of the PC on/off momentary switch, so:
* is the voltage high enough to trip the relay?

hmmm, getting trickier. you see, the relay i use is to actually SWITCH the pc on. what sort of switch have you got? if you can use a double pole type switch then one set of switch contacts does its thing with the pc, the other set can be whatever voltage you want for the relay. i think for instance my relay is powered by the powerpack of the speakers, which is about 12 volts. if you have a 5v supply on your power pack, then a 5 or 6 volt relay should work.

[Mickey Juice]

hmmm, the DPDT might be the way to go. So when I press the button momentarily to turn on the PC, the voltage on the other contacts flows, switching the relay....

I thought of doing it that way, but minus the relay (just wire the monitor on/off button direct to a DPDT switch on the cab... only one problem. If i shut down the PC via mamewah, then need to restart... I'd press the cab button, the PC would boot BUT then monitor would then turn off! They'd be out of sync

So i'd have to wire it (realy) to something like the speaker powerpack like you mentioned... but this voltage would be constant, when I only need a momentary pulse  unless it works like yours, stays closed for a split second...

I have to do some experirments... 

i'm guessing having the monitor switch shorted out all the time may cause some problems if I went down that route.

re: your question, the button is just a pushbutton, with a led inside. It's wired to the PC start jumpers, and to the PC power (LED) jumpers, so it lights up when the pc is on.

[Buddabing]

I have almost completed my cocktail mame cab, but I have one small problem I'd love to elimate.

When I first turn on the cab from the wall, I have to open up the lid and manually press the monitor button, then it goes into standby mode and is ready to use when I power up the PC (single button on the cab).

This wouldn't be a problem if I was to leave the power on all the time and have the monitor sitting in standby mode. I dont want to do this.

Has anyone had this problem and over come it?

I thought of wiring the monitor button to the cab button using a DPDT pushbutton... but there will be a problem if I shut down the computer and then restart with the button ie the monitor will then turn off while the PC is on.

I'm thinking: Wire up a circuit with a relay (similar to what people use to power on their cabs with a single button...) so when I turn on the mains power the relay triggers the monitor switch, putting it into standby mode/turning it on. The relay would only have to close the circuit momentarily. This possible?

Peale worked out a usable relay circuit. Try searching for that thread.

I would just use a SmartStrip, if they work with your voltage.

[Mickey Juice]

Thanks i'll have a look for the circuit.

A smartstrip wouldnt work, getting power to the monitor is no problem. Having to manually press the monitors power button is the problem (it's momentary push button, it wont stay on after power is lost).

[Mickey Juice]

Okie Dokie, I think i've found a solution. Much like Peale I need a momentary switch that will activate briefly when power is applied to the cab.
Instead of turning on the PC, mine will turn on the monitor after the mains power is applied or when the PC is turned on. Most likely when mains power is applied to stop it all getting out of sync.

So I think the solution is a time delay relay.
* Turn on the power to the cab
* leave the relay closed so it turns on the monitor instantly, after a short amount of time the relay activates, breaking the circuit (remember the monitor button is momentary)

Here's a time delayed relay kit from Jaycar (Australia):
Based around the ever-popular 555 timer this kit can be set to trigger from anywhere between 100ms to approximately 20 minutes. The timer controls a relay with both N.O. and N.C. contacts so it can be used to switch a device on or off for the timed period. Features reverse polarity power protection, strt & reset switches and variable time control.
- Kit includes silk-screened solder-masked PCB (60x42mm), relay and all electronic components.
- 12 - 14VC required.

JayCar.Com.Au Link



Here's another interesting relay switch kit:
This kit will close a relay's contacts with as little as 5mA to trigger the circuit. Literately any kit you see on these pages that uses an LED as a trip-condition indicator, can be used with this nifty project. Use the relay to sound buzzers, switch on lights, operate solenoids, trigger alarms, etc. Kit includes Kwik Kit PCB, relay plus electronic components
JayCar.Com.Au Link

[Mickey Juice]

*bump*

Thought I'd post my solution here incase anyone else comes across this problem.

I'm finally getting back to finishing off this project, as I never solved the monitor problem (built the relay timer kit, just didn't try it out).

Thanks to Dave on the Aussie Arcade forums, he's build the ideal solution:

Dale (DM247) & I were just discussing this very issue today. I have just designed a small board with a micro, relay and switch inputs. It's for TV's that power up in TV mode instead of AV mode. The idea is that my little board waits a few seconds after power-up, then pulses the TV/AV switch via a relay.

It could also be useful for monitors that power up in the standby mode. You can try a simpler timer that just keeps the relay on from power-up for a few seconds but I've found that a lot of PC monitors (and TVs) will ignore the button if it's pressed when the monitor is powered-up.

You need to power it up, wait a few seconds, then pulse the button. My new board will do all of this. Price is looking to be about $25 at this point. Installation should be easy. You just need 12V (or 5V) and access to the button to connect the relay contacts. Well within the DIY arcader here!

I've pre-ordered it from his website:
Audio Visual Devices

This board has both voltage (5V - 12V) and contact (button) trigger inputs and a normally open relay contact output. It waits for several seconds after being triggered (or powered up) and then pulses the relay output.

This enables it to be connected to a TV in an arcade cabinet so that it switches over to AV mode automatically. A lot of TV's always power-up in TV mode, so this is the perfect solution.

A similar situation exists with some PC monitors. They need to have their power button activated after power-up otherwise they sit there in "power save" mode, even though they are getting a valid signal from the arcade PC.

Will post up when it's installed.