2020. 3. 2. 03:16ㆍ카테고리 없음
This is a circuit converter from VGA in TV SCART connection. Basically it is a circuit that accepts the signals from the exit of card VGA, him it then changes in combination RGB+composite sync and it leads to fastener SCART. The elements of picture from her exit card VGA, RED, BLUE and GREEN are already ready, bring right tendency the 0.the 7 vpp and right resistance of 75W for direct connection with fastener SCART,for depiction in the TV. What should it changes it is the rightcombination the horizontal and vertical synchronization signals from theVGA in a complex signal that will be led to the entry VIDEO in pin SCART.
This transformation him they undertake electronic elements of circuit. That It Functions:This circuit has been drawn in order to it changes regular signals VGA, standard RGB and the complex signal of timing. Circuit is simple because signal RGB from the VGAis ready in standard level 0,7 Vpp and in 75W charge. For the signalsof timing exists a circuit that changes the horizontal and vertical incomplex. The circuit is simple based on a TTL completed with four gates XOR, two resistances and two capacitors. His choice completed TTL it is reasonable because the signals of timing of VGA they are signals TTL.The converter of signals of timing is system that regulates thedifference of polarity of signals, so complex signal it is always right.Card VGA uses different polarities in thesignals of timing in order to it informs the Monitor anymore analysis ituses.
This circuit regulates the changes polarity the signals in leastfrom 200 mSec, that are faster and from the time of regulation of commonMonitor VGA. The circuit in order to function need stabilized tendency + 5V (+/- 5%) and current 120mA.Manufacture:Converter VGA in TV is easy in themanufacture to him it is enough exists a relative experience in themanufactures electronic. The circuit can be manufactured on one small EPOXYboard. Remember only to connect also the completed circuit with thecatering of 5V (in the drawing it does not appear). The circuit in orderto it rightly functions it needs without fail stabilized tendencyconsequently it should you use also a REGULATOR LM7805.In the entry the 7805 the tendency should be from 9 until 16V sothat it accomplishes us it gives the desirable stabilized tendency of 5Vin his exit. Tendency from 9 until 16V we can him take also from ourcomputer or from exterior small power supply’s socket.
From the computerwe can we take from the following points: from door RS232, from theparallel door, from the PS2 and finally from a gambling chip ofcatering by his interior computer.Big attention should be given in him you stick that you will makeand in the wiring of circuit, you avoid the chills you stick why thecircuit functions in big frequency and sure will be createdinstabilities in the circuit with result bad quality of picture or evenlack timing in the screen of TV. Be careful in order that the solderingis clean and glazing thus you will only be sure that the soldering hasbecome right.
For the wiring you are used shielded cables blentaz andground the thorax of cables in the board’s chassis. Good it ismanufacture it is placed in a plastic box and it is placed and aconnector EURO/scart female for placement in chassis.Materially:U1: 74LS86C1: 22mFyC2: 2,2 mFR1, r2: 2k2R3, r4, r5: 2k2R6, r7, r9: 47kR8: 120T1, t2: 2N2222Cable of connection VGA male 15pin sub D (DE 15)Output connector 21pin EURO/scart female.
I want to connect my DVD player which has a SCART output to a computer LCD monitor with VGA input. The DVD player supports the Progressive scan mode. It supports both PAL and NTSC.I've built and it 'works':In PAL mode, the monitor is showing 800 x 600 @ 50 Hz and in NTSC 640 x 480 @ 60 Hz.Only one problem: the image is greenish. First I thought I miss-connected or didn't connect R and B signals, but if I look at the picture it has red and blue colors too.
Scart To Hdmi Cable
White picture appears green. Red and blue appear darker than normal. There is a green tint over the picture.One thing I noticed: the whole signal is transmitted via the green wire. I can disconnect all, if I leave green and ground connected I get picture. The two transistor circuit appears to have no use at all because it works the same without it (as long as I provide R, G, B).
This makes me believe that the green signal is also carrying sync data (sync-on-green).I've tried adding potentiometers, capacitors over green signal but with no luck. The picture disappeared. I've tried all possible settings on my DVD player. It only works with progressive scan enabled.UPDATE: I guess I found the cause on:If you connect a component signal to an RGB input, you’ll only get a green image.
The R and B output will be very low.It is exactly what.What can I do to make the green color less intense? Will a simple transistor voltage amplifier for the Red and Blue channels solve things? This might come a little late, but you need to boost red and blue, not lower green, because apparently you're outputting component (YPbPr) and not RGB. You can use an amp to do that like the Texas Instruments THS7314 (I think you can order that stuff from AliExpress, not sure though) or you can use a method that may be unsafe, but it works, that is using 220uF capacitors on the red and blue signals.
I used those capacitors when doing a component mod to a Super Nintendo some time ago and so far no TV has died or exploded, so I guess it's safe enough.One question though, that has me quite curious. You managed to separate the sync signal into H and V for VGA or your monitor supports composite sync?