New mame build, need to power monitor help??

[excaliburlives]

   Hello, i'm making a new mame build from an empty gutted arcade 1up cab. I already built the pc and want to install a a 23" acer monitor that runs off a 12V power supply. Can i just tap into a 12v rail on my pc's PSu and get abarrel connector to power ir? I'm thinking i might mess something up. I'm afraid of the amps not the volts. Is this possible anybody? Looking for an expeert in this sort of thing. Thnaks for any help or advice i can get.

[Ond]

   Hello, i'm making a new mame build from an empty gutted arcade 1up cab. I already built the pc and want to install a a 23" acer monitor that runs off a 12V power supply. Can i just tap into a 12v rail on my pc's PSu and get abarrel connector to power ir? I'm thinking i might mess something up. I'm afraid of the amps not the volts. Is this possible anybody? Looking for an expeert in this sort of thing. Thnaks for any help or advice i can get.

Generally, should be fine. Assuming the PSU you want to tap is rated at enough watts, you haven’t provided info about that. Check the current rating on the monitor as well. Finally what GPU are your using? If it’s just on the MB it won’t draw that much. Separate higher end GPUs can draw a lot of current. Need more facts.

[excaliburlives]

Well, like the the idiot that I am, lol. I tried it out and fried the monitor. Smoke came out the back so it’s done.  Just picked up another one on eBay for $30 ($30 lesson learned). I’m running a dozen 5 5600 with a gtx 1060 on 600wPSU. How can I avoid making the same mistake twice? Is there a module out there? I could use to help turn down the amperage?

[Ond]

Well, like the the idiot that I am, lol. I tried it out and fried the monitor. Smoke came out the back so it’s done.  Just picked up another one on eBay for $30 ($30 lesson learned). I’m running a dozen 5 5600 with a gtx 1060 on 600wPSU. How can I avoid making the same mistake twice? Is there a module out there? I could use to help turn down the amperage?

Well, we all learn by our mistakes including me  .  So before you go connecting up the next monitor here's a few suggestions. Take a pic of the label or info on the back of the monitor that provides power details and post it here.  Need to check both the voltage and current rating as well as the polarity of the connector. Assumptions are dangerous, facts are everything.  Is it really powered by 12V what is the polarity of the plug normally used with it, stuff like that. 

Another question. Did you actually connect 12V?  That's a yellow +wire and a black -wire from the PSU.

Here's an important bit of electrical knowledge.  Electrical devices use as much amperage as they need. Say your PSU has available 12V at 6 amps and your Monitor is rated at 12V/3 amps it will only use up to 3 amps of the what's available .   There is no "turn down the amperage". Voltage on the other hand especially for electronic DC devices has to be close or right on the right amount. 12V needs 12V or close to it.  There are exceptions to the current used by components, for instance a naked LED WILL draw all the current it can get until it blows without some sort of resistor in the circuit. The amount of total power a device uses is expressed in watts. Watts (W) = Amps (A) × Volts (V) If your monitor is 12V/3A then it would be 3 x 12 = 36 watts.  Not much when you have around 600w to play with.  I work in electronics retail. A common problem I see is people buying power packs whose amperage rating is too low. Their device needs 2.5 amps but the power pack they buy is only rated at 1 amp. They come into the shop complaining that the power pack "doesn't work".  Another problem is they have the DC plug polarity around the wrong way and "my power pack doesn't work". Buying a power pack that's rated at more amperage than you need is fine, so long as the voltage is correct.

I hope that info is useful to you. 

[excaliburlives]

I did tap into the yellow wire from the mole connector, which is 12 V, the red wire was 5 V. Not sure why it fried the monitor up but here are some pictures. Thanks very much for the help so far.

[excaliburlives]

Just noticed it was supposed to be 19v if I reading it right. The power adapter is the wrong pic. Shouldn’t matter since that’s not what fried the monitor. The 12v from the psu did that.

[Ond]

So, the new monitor needs 19V?  That is a very common voltage for LCD monitors. A quick check of the suitable power supply for that monitor reveals these facts:

•   DC 19 volts drawing 3.42 amps = 65-watt power consumption.
•   The DC plug into the monitor is centre pin positive.

Your original idea for using your PCs PSU is no longer applicable.  Getting 19 volts from a PC PSU is not practical. Even combining the 12V + 5V gives only 17V and the current supply (amps) using that method is unreliable. It is possible to modify a PC PSU to give 19V but that is beyond the scope of this project.

Some options to consider:

•   Use a power board in the cab and just plug the monitor supply adapter into it.
•   Use a DC-to-DC converter that can take 12V from the PSU and boost it to 19V (rated at around 4 or 5 amps). There are many DC-to-DC converters available, eBay, Amazon, Ali Express etc.

Plenty of BYOAC folk use a power board of some sort in their cabs to power monitors, it’s probably the easiest solution for you.

[excaliburlives]

Well, the used mintior came in from ebay and its broke. On the hunt for another monitor now. 

 I guess i have nothing to lose by openening up the one i fried and see if i can fix it. Still don't know how i fried a 19V monitor with a 12V line from the PSU?? Trying to understand how and why it happened so i can learn from my mistake and try to improve my skills. I found the original power supply.  Thank you. I Appreiciate the insight.

[danny_galaga]

Seems likely you either got the polarity wrong, or it was way more than 12v. There is a chance too of course that actually, it was that monitors time to shuffle off this mortal coil

[excaliburlives]

Gotcha, well going to give it another try. Wish me luck , lol.

[excaliburlives]

I’m taking Omd’s andvice.  I  ordered a step-up converter. I will report back after I test it. Thanks again guys.