Computer Monitor Conversion AC to DC

[Oshi]

I have an external Acer AL1716 A 240 volt AC monitor attached to by wee netbook computer which I was wondering if it can be converted to a 12 volt DC powered monitor. I haven't pulled the Acer monitor apart yet and thought perhaps I should ask here if anyone knows a little bit more about the unit before going to the trouble to see what's inside.

[japlytic]

Re: Computer Monitor Conversion AC to DC

Welcome, Oshi!

Monitors which do not use an external "brick" power supply are a bit tricky to convert to 12V; however, some with an external "brick" power supply can run on 12V, often requiring a DC-DC converter.

[budm]

Re: Computer Monitor Conversion AC to DC

You will also need to convert 12v to 5v for the logic board. You do not want to use inverter?

[Oshi]

Re: Computer Monitor Conversion AC to DC

Welcome, Oshi! Monitors which do not use an external "brick" power supply are a bit tricky to convert to 12V; however, some with an external "brick" power supply can run on 12V, often requiring a DC-DC converter.

This one is internal and I was hoping it would be a matter of bypassing a 240V external supply and attaching to the internal power supply and hoping it would be 12 volt. I have made a couple of 12 volt variable power units which knock down to 3 volts by turning a 20k variable type resistor. So really I need to open up the Acer Screen and take a look inside. I really wouldn't know where to start looking but I will give it a try.Any advise would be grateful.

You will also need to convert 12v to 5v for the logic board. You do not want to use inverter?

I'm trying to avoid an inverter and make by whole internet system 12volt Unfortunately my system is too small by converting with my 150watt inverter.
I checked out the Acer screen and it takes 1.2 amps DC when its plugged into the inverter. I can measure amperage usage with my home's 12volt regulator's display, and which is connected to my small battery bank.

[Oshi]

Re: Computer Monitor Conversion AC to DC

Had a bit of a goosey gander under the bonnet and realised it's out of my league. Maybe I should track down a 12 volt monitor. Anyone know of such a thing, brand etcetera. I did a google without much luck. Surely boaties must use something along this line other than a 12 volt TV.

[budm]

Re: Computer Monitor Conversion AC to DC

If I were to do it, I will take out the power supply board and replace the backlights inverter with this board: http://www.ebay.com/itm/Universal-CC...item41606f799e

Then use a simple linear regulator to drop 12v to 5V for running the logic board.
The on/off control of the backlight can be done by using a switch and a pot for adjusting the brightness of the backlights.
Does you monitor look like one of these ACER?
http://s807.photobucket.com/albums/yy352/budm/ACER/

[Oshi]

Re: Computer Monitor Conversion AC to DC

If I were to do it, I will take out the power supply board and replace the backlights inverter with this board: http://www.ebay.com/itm/Universal-CC...item41606f799e

Then use a simple linear regulator to drop 12v to 5V for running the logic board.
The on/off control of the backlight can be done by using a switch and a pot for adjusting the brightness of the backlights.
Does you monitor look like one of these ACER?
http://s807.photobucket.com/albums/yy352/budm/ACER/

Thanks for that. I've order the inverter today. I will give it a go.
The monitor is anAL1716 A and version AL1716Ab whatever that means.

Have you seen these? I couldn't find anyone who retails them.Only two wholesalers in China. You can get 8" and 10" versions as well.
http://factory.dhgate.com/lcd-monito...p43071283.html

[budm]

Re: Computer Monitor Conversion AC to DC

Something fishy in the spec, it says 5V, 500mA USB powered, but the power consumption shows "Power Consumption: 4W-5W " How can you get that much brightness and power to run all the logic at 2.5W (Max power for one USB port), unless it uses one of those USB Y cable to use 2 USB ports to get enough power to run it. You may be able to get car adapter that convert 12V to 5V for it.

[Oshi]

Re: Computer Monitor Conversion AC to DC

Something fishy in the spec, it says 5V, 500mA USB powered, but the power consumption shows "Power Consumption: 4W-5W " How can you get that much brightness and power to run all the logic at 2.5W (Max power for one USB port), unless it uses one of those USB Y cable to use 2 USB ports to get enough power to run it. You may be able to get car adapter that convert 12V to 5V for it.

I checked their 7 inch and it is powered similarly. They sell a 10 inch and it's 12 volt powered?
Another company is flogging the same unit.
I was going to email them and ask some questions but there's only provision to do so by companies.

http://newaye.en.made-in-china.com/p...-CLi156B-.html

[Oshi]

Re: Computer Monitor Conversion AC to DC

If I were to do it, I will take out the power supply board and replace the backlights inverter with this board: http://www.ebay.com/itm/Universal-CC...item41606f799e

Then use a simple linear regulator to drop 12v to 5V for running the logic board.
The on/off control of the backlight can be done by using a switch and a pot for adjusting the brightness of the backlights.
Does you monitor look like one of these ACER?
http://s807.photobucket.com/albums/yy352/budm/ACER/

The inverter came yesterday. Is it straight forward to replace and recognise where it goes?

[mariushm]

Re: Computer Monitor Conversion AC to DC

I have that exact model of universal inverter.

As in the picture, it has four wires and they're labeled on the back side... power (Vin) , ground (GND), adjust brightness (ADJ) , and enable/disable (ON/OFF)

The Vin goes to where you have 10v or more on the power supply, GND goes to ground.

The two other wires, adjust and on/off are to be connected on the display board and there should be two wires from the old power supply going to the display board.

Either on the power supply or on the display board, there should be by the connectors text saying what each wire does (or pins in a connector do)

If you can't tell which is what, the adjust wire should have a voltage of around 2-4 volts, depending on what brightness you used before. The On/Off pin should have 5v coming from the display board when the backlights are supposed to be on, nothing when the monitor is supposed to be in standby.

[Oshi]

Re: Computer Monitor Conversion AC to DC

I have that exact model of universal inverter.

As in the picture, it has four wires and they're labeled on the back side... power (Vin) , ground (GND), adjust brightness (ADJ) , and enable/disable (ON/OFF)

The Vin goes to where you have 10v or more on the power supply, GND goes to ground.

The two other wires, adjust and on/off are to be connected on the display board and there should be two wires from the old power supply going to the display board.

Either on the power supply or on the display board, there should be by the connectors text saying what each wire does (or pins in a connector do)

If you can't tell which is what, the adjust wire should have a voltage of around 2-4 volts, depending on what brightness you used before. The On/Off pin should have 5v coming from the display board when the backlights are supposed to be on, nothing when the monitor is supposed to be in standby.

I must admit of being a novice at this.
I used this link to help me get the monitor apart.
http://martybugs.net/electronics/Acer-AL1716-caps.cgi

I gather you are referring to the 2 PCB boards that can be un-hooked. Is
the larger one not used anymore as it is only the power supply and can be discarded? I noticed the inverter has the 4 plugs for the monitor. So the smaller PCB is connected to the inverter as you described to that 6-pin connector (circled in figure 11 below) as described in the link I used.
Do you need to solder it in some how? I noticed there are 8 pins. Four lots doubled up somehow? How do you connect to thees pins.
Also where do you put in the 12 volt supply?
Thank you and budm for any assistance.

[mariushm]

Re: Computer Monitor Conversion AC to DC

The power supply (the big uglier board with the mains plug) is connected to the smaller display board with that 8 pin connector.

It's possible they used that 8 pin connector simply because it was the most convenient or because it was more reliable or provided a better connection.

The monitors usually run on 5v and 3.3v and sometimes 1.8v.
The lamps usually run from 12-16v which gets converted by the inverter to 600-1000v.
Sometimes, this power supply also sends 12v to the display board, in case the display board also has a small audio amplifier for speakers.

So the big power supply's purpose is made out of two sides - the actual power supply which creates around 12v for the inverter and usually 12v and 5v for the display board.

You can get rid of the big board if you have a way to give 12v to the inverter and the display board, and a separate 5v to the display board separately.

In your exact case, after looking at the service manual for the monitor, that 8 pin connector is like this:

1. ON/OFF monitor
2. Adjust brightness
3. 12v
4. Ground
5. 5v
6. 5v
7. Ground
8. Ground

Usually, pin 1 is the top left pin in that 8 pin connector on the power supply and pin 5 is the bottom left pin, but you can be sure by testing with a multimeter.

Disconnect the two boards, remove the big power supply board from that metal case, put it on a few big sheets of paper or a cardboard sheet so that no part of it touches anything, carefully plug the cable into the connector then plug the cable into the wall socket.
Now get the multimeter, put it on DC, if it doesn't autorange put it on 20v or some value similar to that, put the black probe on the top right pin and the red probe on the 3rd pin from the top.
If you see 12v, then it means the 3pin is 12v, so the layout above is right.

So now you have all four pins for the inverter: on/off , adjust brightness, 12v, ground all at the top.
The first two pins on the bottom row are 5v for the display board. Easy.

Now, if you have an external 12v DC power supply, you can simply remove the power supply board completely.

You only need to generate that 5v for the display board. This can be done with a linear regulator. The classic 7805 will do, you can find it on eBay or shops under various names, but as long as it has 7805 in the name and can provide at least 1.5A it will do.



So as you can see it's very simple: 12v goes into the first pin, out comes 5v from the third pin. You just need those capacitors to made the output smoother.

You will however have to be careful because this chip will stay hot as long as it runs, so you can't just stick/tape it to the back of the screen. You should unscrew one of those metal plates (heatsinks) from the power supply board, screw this chip to it and then screw the metal plate to one of the old screw holes where the big power supply board was screwed to.

[budm]

Re: Computer Monitor Conversion AC to DC

Can you post good clear pictures of the power supply-inverter board, both sides?

[Oshi]

Re: Computer Monitor Conversion AC to DC

Thank you mariushm for the detailed info. I will need to digest this tonight when I have a few moments.

Can you post good clear pictures of the power supply-inverter board, both sides?

Couldn't get both photos up together. Here's two close ups.
http://sphotos-g.ak.fbcdn.net/hphoto...86854495_n.jpg

http://sphotos-e.ak.fbcdn.net/hphoto...60320626_n.jpg

[Oshi]

Re: Computer Monitor Conversion AC to DC

[QUOTE=mariushm;283294]
The monitors usually run on 5v and 3.3v and sometimes 1.8v.
All at the same time or only one?

The lamps What are the lamps?
usually run from 12-16v which gets converted by the inverter to 600-1000v.
Sometimes, this power supply also sends 12v to the display board, in case the display board also has a small audio amplifier for speakers.


You can get rid of the big board if you have a way to give 12v to the inverter and the display board, and a separate 5v to the display board separately.
I can supply both 5 and 12 volts.

[mariushm]

Re: Computer Monitor Conversion AC to DC

I was talking in general.

Yes, generally monitors need several voltages but use a power supply to generate one or two of them at high current, then use some very small converters to generate the smaller voltages on the display board.

In your particular case, on your monitor, the big power supply only generates 12v and 5v, and the display board has on it a small dc-dc converter which generates 3.3v (and maybe another one for 1.8v but I didn't check the service manual in great detail)

Anyway, you only have to care about 12v and 5v, these two are needed by the display board. The inverter only needs 12v or more.

If you can use a small power supply (adapter) to provide both 12v and 5v directly, that's great, but it would really be better if you'd use a DC-DC converter to generate that 5v from 12v.

This is because if you have long cables, you may not actually get 5v at the end of the wires, and also there may be noise, interference which can affect the quality of that 5v input

That small circuit I put a picture of above, makes sure the 5v it generates is very smooth, clear of noise, and as it's produced inside the monitor, very close to the connector, you will almost definitely have no problems.

The only concern is like i said, heat... but that's easily solved if you leave it screwed on one of those rectangular metal bars that are used on the old power supply board.

But feel free to test with 12v and 5v directly from something before, you won't do anything bad with it. If the monitor resets or acts out, consider doing like I said.

[Oshi]

Re: Computer Monitor Conversion AC to DC

Anyway, you only have to care about 12v and 5v, these two are needed by the display board. The inverter only needs 12v or more.

So you only supply 12 volts to the inverter. I gather it's the 4/6 pin connector in the middle between the caps in the above photo? Colour of the wires are red, black and two yellow. I guess now is how to wire/solder what to where?

If you can use a small power supply (adapter) to provide both 12v and 5v directly, that's great, but it would really be better if you'd use a DC-DC converter to generate that 5v from 12v.

I have made a couple of DC to DC variable units using the IC LM317T which can be plugged into 12 volts to be turned down using a variable resistor to give 5 volts.

.

I checked the voltage of the pins and they were different from those you listed.
Looking at the back of the pins on the power board toward the connector of the disconnected display board.

left to right
top row... 1= -0volts, 2=5volts, 3=grd, 4= 14volts,
bottom row... 5= -0.12volts, 6= 5 volts, 7=grd, 8= 14 volts

[mariushm]

Re: Computer Monitor Conversion AC to DC

That's OK, very good of you that you checked.

I got those from a service manual, but the pictures showed probably an older revision of the power supply using a connector having all those 8 pins in a single row.

14v is actually 12v, but the power supply is not regulated.. When the monitor isn't running or the lights are off, the power supply idles at 14v but as soon as something draws power from that, the voltage will go down towards 12v

So now your 12v and 5v pins are obvious, but it's not so obvious is which one is the on/off pin for the inverter and the adjust brightness pin.

Connect the two boards together, put the red probe on one of pins 1, 5 , 3, 7 and plug the monitor in the mains socket. You don't have to connect the lamps.

The display board should send the command to the inverter to turn on, which is done by sending 5v to the on/off pin.. so one of those pins that weren't 5v or 14v before should be around 5v, at least for a brief moment until the monitor goes back to stand by. If it remains ground or zero, remove the plug from the socket, move to another pin and plug it again.

While you do this, one of the pins you check would be the adjust pin, which should have something between 1.5-2v and 5v... 5v would be the highest brightness possible. Since it's unlikely you had the monitor on highest brightness, you should see on the pin something less than 5v.

I have made a couple of DC to DC variable units using the IC LM317T which can be plugged into 12 volts to be turned down using a variable resistor to give 5 volts.

That's great, so you're already familiar with making up something like this. As you won't adjust the voltage, you would be able to change the variable resistor with a fixed one.

The output doesn't have to be exactly 5v, so don't be concerned if the resistor combination gives you 4.9-5.1v, that's close enough.

The beauty of that 7805 is that it's fixed, it doesn't need resistors for the feedback, so it's kind of "idiot proof". But it's not worse or better than a LM317T for this purpose.

[Oshi]

Re: Computer Monitor Conversion AC to DC

I did the test this morning and could only find 3.3volts from pin #1.
No voltage could be seen from pin #5.
Would that voltage be correct?

It was a bit fiddly and the contacting points were difficult together with pulling the 240 volt plug in and out.
I'll try again this evening.
I need to go out and pull my car's back caliper apart now.