TV RGB mod thread

[numbski]

I am feeling a bit dumb. I have done this mod a few times without issue, but this time around I am getting AC power somehow flowing through my 4PDT toggle switch, and AC noise if I leave it on composite video - I can see a ghosted version of the picture, along with AC distortion. If I touch the metal housing of the toggle, the screen behaves as if I have caused a short. :\

https://www.evernote.com/shard/s3/sh/58 ... 733aac016d

The 4 pole pins are wired to the jungle IC at Ys, Red, Green, and Blue - these are out-of-circuit. The first throw is wired to the original points Ys, Red, Green, and Blue were into circuit. The second throw I have a 150k resistor from pin 3 of an 7805 on the chassis to the Ys pin, and then Red, Green, and Blue are wired to the top 3 pins of a mini-din-8 female plug with a 0.1uf 50v cap in-line, and a 75ohm resistor to ground - that ground is the shared audio/video ground for the TV's line-in.

The composite sync pin on the mini-din-8 is run to the center pin for the lone composite in, and all of the ground points on that plug tie to the shared audio/video ground for the line in. I also went ahead and tied the two audio pins on the mini-din connector together and ran that to the center pine of the composite audio line-in.

It is really weird. The screen flickers if I touch that housing or the RCA grounds. The TV only has two prongs, and I don't see a grounding screw to earth the thing.

[numbski]

Actually, it looks like the chassis has a pin for earth, it just isn't being used. Checking resistance to that point shows 525ohms of resistance to the chassis frame. Beginning to wonder if I should add a 3 prong power cable just to be sure. :\

[MarkOZLAD]

Marcos.

Here is how I would wire up to a scart port.

http://imgur.com/a/9HVgT

[MarkOZLAD]

Hello Mark
Perfect, will do directly into the J281 from the top and solder them from the botton as you suggest, no problem!
Now about those 75ohms resistor, give a look on the photos how i will be wiring the mod, those 6 wires will came from the Ultimarc VGA Amp, including the 5v, let me show you the picture.

https://goo.gl/photos/GQGfuVWMBLByEiYX8

Now do you think even with the VGA AMP circuit behind the mod will be necessary the 75ohms resistors ?

Thanks a lot!
Marcos

Hey Marcos,

I somehow overlooked this post. I don't know anything about those VGA AMP circuits. My experience is with Scart RGB. I guess you can try without and if it doesn't work, add them in.

There are a fair few VGA to Scart wiring diagrams on the net.


EDIT: Just checked out https://www.ultimarc.com/vidamp.html

I don't think you want to use this AMP. I think you want to get a female 15 PIN DIN socket and wire directly from there or buy a VGA to Scart adapter. The Ulitmarc Video amp will amplify the VGA signals. YOU DO NOT WANT THAT! The TV will accept RGB signals with 0.7V Peak to Peak. Standard VGA already provides this. This amplifier will amplify the RGB signals to 4V Point to Point. It may be possible to use the Ultimarc amp to combine the synch.

As I said VGA to Scart is not my specialty, perhaps someone else can help you with that.

[buttersoft]

Actually, it looks like the chassis has a pin for earth, it just isn't being used. Checking resistance to that point shows 525ohms of resistance to the chassis frame. Beginning to wonder if I should add a 3 prong power cable just to be sure. :\

I've had a similar issue. Picture will come up, but ghosted and full of noise. I haven't found a solution yet.

Admittedly, Sony was the one manufacturer that connected board ground and AC earth, at least on some sets. Where does that earth pin go? Every set I've seen bar about two has a three pin connector, but is only ever designed to connect to the active and neutral.

It might even be the power you're using for the blanking voltage getting noise somewhere. Try using 5V from your video source instead, mb?

Keen to hear if you do manage to solve the issue.

[Syntax]

I am feeling a bit dumb. I have done this mod a few times without issue, but this time around I am getting AC power somehow flowing through my 4PDT toggle switch, and AC noise if I leave it on composite video - I can see a ghosted version of the picture, along with AC distortion. If I touch the metal housing of the toggle, the screen behaves as if I have caused a short. :\

https://www.evernote.com/shard/s3/sh/58 ... 733aac016d

The 4 pole pins are wired to the jungle IC at Ys, Red, Green, and Blue - these are out-of-circuit. The first throw is wired to the original points Ys, Red, Green, and Blue were into circuit. The second throw I have a 150k resistor from pin 3 of an 7805 on the chassis to the Ys pin, and then Red, Green, and Blue are wired to the top 3 pins of a mini-din-8 female plug with a 0.1uf 50v cap in-line, and a 75ohm resistor to ground - that ground is the shared audio/video ground for the TV's line-in.

The composite sync pin on the mini-din-8 is run to the center pin for the lone composite in, and all of the ground points on that plug tie to the shared audio/video ground for the line in. I also went ahead and tied the two audio pins on the mini-din connector together and ran that to the center pine of the composite audio line-in.

It is really weird. The screen flickers if I touch that housing or the RCA grounds. The TV only has two prongs, and I don't see a grounding screw to earth the thing.

Remove the audio lines you wired to the set and see if it clears it up.
I've had issues with a.c. like interference and it turned out to be poor audio cables.

After looking at the jungle why are you using ys? I would of thought pin 9 was blanking.

Would of used 10 11 12 for rgb input too and wouldn't of hurt the osd

Ys is actually a sync input pin it seems dude. Your putting voltage to sync... Find the blanking or hijack the osd.

[elvis]

There are a fair few VGA to Scart wiring diagrams on the net.

EDIT: Just checked out https://www.ultimarc.com/vidamp.html

I don't think you want to use this AMP.

The Ultimarc Video Amp is designed for arcade monitors, not consumer televisions. It amplifies the 0.7-1V signals that VGA and SCART expect up to 4-5V that an arcade monitor expects.

Definitely don't use this on a regular TV chassis, as it could do damage.

I've got 2 of these Ultimarc Video Amps in use. One on a genuine arcade monitor, and one on a TV I converted to an arcade monitor with a chassis swap (using a Jomac Universal Chassis). For that purpose and price, they are brilliant.

[MarkOZLAD]

Remove the audio lines you wired to the set and see if it clears it up.
I've had issues with a.c. like interference and it turned out to be poor audio cables.

After looking at the jungle why are you using ys? I would of thought pin 9 was blanking.

Would of used 10 11 12 for rgb input too and wouldn't of hurt the osd

Ys is actually a sync input pin it seems dude. Your putting voltage to sync... Find the blanking or hijack the osd.

Yep, Ys is sync. I'd put RGB through 16,17 and 18. Not sure it needs a blanking voltage. I find the datasheet a little confusing, it seems to say that just by putting the sync through Ys will put it into RGB mode. Otherwise try pin 9 i guess.

[m.andrade1]

Hello Mark
Thanks you so much for your advice, i was ready to proceed with the mod today!, now i will revise it again.
I found an alternative cable that i already had, it´s a vga cable that i used on my Revenge from Mars pinball, it´s a vga female standart in one point and the other a 10 pins Well´s Gardner default, let me show a picture.

https://goo.gl/photos/5hZNPUYAx5yoMwvk7

I think i can get all the necessary wires from this 10 pin connector (red, green, blue, sync, gnd), without the amp, now for the 5v i think i will hack a ordinary usb cable and get the 5v from the usb port of the pc, i thinks it´s safer than the directly from the power supplier.
Now i think will use the 75ohms resistor with that configuration, do you know how many watts the resistor have to be?
Here in local eletronics store, they have only 82ohms 1/4wats do you think it will work ?

Thanks a lot again
Marcos

[MarkOZLAD]

Hello Mark
Thanks you so much for your advice, i was ready to proceed with the mod today!, now i will revise it again.
I found an alternative cable that i already had, it´s a vga cable that i used on my Revenge from Mars pinball, it´s a vga female standart in one point and the other a 10 pins Well´s Gardner default, let me show a picture.

https://goo.gl/photos/5hZNPUYAx5yoMwvk7

I think i can get all the necessary wires from this 10 pin connector (red, green, blue, sync, gnd), without the amp, now for the 5v i think i will hack a ordinary usb cable and get the 5v from the usb port of the pc, i thinks it´s safer than the directly from the power supplier.
Now i think will use the 75ohms resistor with that configuration, do you know how many watts the resistor have to be?
Here in local eletronics store, they have only 82ohms 1/4wats do you think it will work ?

Thanks a lot again
Marcos

1/4 watt resistors will be fine. Not sure about 82ohm though. Strange they don't have 75ohm. It's a very common size. Are there no alternative suppliers? Internet sites with overnight shipping?

The vga breakout cable looks good but how will you get Composite sync? Does your video card output csync? I have heard of people just twisting the two hsync and vsync wires together. Might be ok because we are going to send it through a port that expects Composite video. I don't think it's the recommended option though.

Good luck with it. Would really like to see it work for you.

[m.andrade1]

Hello Mark
Brazil things are complicated, will try buy online, 1/4w are more common, will use the 75ohms, will not risk the project with 82ohms, no way.

The mod has began !
https://goo.gl/photos/zqjmVdnL249YgNj9A

Exactaly ! To get the composite sync, i will twist both h+v sync into 1, or jump wire the V into the H, already did it and worked with the Vga amplifier.

Thanks a lot for Elvis with perfect explanation about what tv set needs to fill, i usually plug arcade chassi, so that info save me from fry the tv original chassis!
Soon will post news !

Marcos

[lukilla]

If you can find a broken vga monitor nearby you could get those resistors.

[numbski]

Remove the audio lines you wired to the set and see if it clears it up.
I've had issues with a.c. like interference and it turned out to be poor audio cables.

After looking at the jungle why are you using ys? I would of thought pin 9 was blanking.

Would of used 10 11 12 for rgb input too and wouldn't of hurt the osd

Ys is actually a sync input pin it seems dude. Your putting voltage to sync... Find the blanking or hijack the osd.

Yep, Ys is sync. I'd put RGB through 16,17 and 18. Not sure it needs a blanking voltage. I find the datasheet a little confusing, it seems to say that just by putting the sync through Ys will put it into RGB mode. Otherwise try pin 9 i guess.

This is why I shouldn't mod when I'm half-asleep. I'm a moron, as stated.

Will make this adjustment and check back later - right now the thing won't even power on. I hear the power relay "click", but the screen doesn't come up, even with the new mod switch to "off". Oopsie.

[m.andrade1]

Hello All
Anyone knows how much is the ideal (AMP) to send the 5v to F blank, i will hack a usb cable that by default on usb port 2.0 send 5v with 0,5A or 500Mah, the other alternative is thru a cheap wall charger that feeds 5v with 1000mah or 1A, what you guys think it´s the ideal feed for the circuit ?

Thanks
Marcos

[ApolloBoy]

Hello All
Anyone knows how much is the ideal (AMP) to send the 5v to F blank, i will hack a usb cable that by default on usb port 2.0 send 5v with 0,5A or 500Mah, the other alternative is thru a cheap wall charger that feeds 5v with 1000mah or 1A, what you guys think it´s the ideal feed for the circuit ?

Thanks
Marcos

Your TV doesn't already have a 5V rail? Even if it somehow doesn't that's a pretty hackneyed way of getting 5V.

[mikejmoffitt]

Hello All
Anyone knows how much is the ideal (AMP) to send the 5v to F blank, i will hack a usb cable that by default on usb port 2.0 send 5v with 0,5A or 500Mah, the other alternative is thru a cheap wall charger that feeds 5v with 1000mah or 1A, what you guys think it´s the ideal feed for the circuit ?

Thanks
Marcos

The current rating of an adapter doesn't represent energy flow. How much current is present will be however much the device draws. The rating on the adapter is the maximum. It should be less than 1mA as an input like this typically has megaohms of resistance.

[m.andrade1]

Hello Mike
Thanks for the reply!
I decided to get the 5v from an outside source because i could't find a sweet spot on the chassis, Mark help me on that task we found a transistor that could supply the 5v, but when i measure the voltage was -5v even with the right leads, my thread start on pag 29, will try with a usb cable hack so i can turn on and off just removing the usb cable from the pc.
Just waiting for the resistor 75ohms to came to proceed with the mod.

Thanks a lot
Marcos

[Syntax]

Hello Mike
Thanks for the reply!
I decided to get the 5v from an outside source because i could't find a sweet spot on the chassis, Mark help me on that task we found a transistor that could supply the 5v, but when i measure the voltage was -5v even with the right leads, my thread start on pag 29, will try with a usb cable hack so i can turn on and off just removing the usb cable from the pc.
Just waiting for the resistor 75ohms to came to proceed with the mod.

Thanks a lot
Marcos

Get a 10k potentiometer connect it to say 7 or 12 v on an outside leg wire blank8ng to center and turn it to full resistance then turn your set on and turn the resistance down till the screen blanks.
Then either leave the pot connected or write down the current resistive value and swap the pot for a similar value resistor

Some jungles require a stable voltage divider to drain current from a pin (usually their pins are sitting high 5v) in this case w8re the pot v one side ground the other and blanking center.

[MarkOZLAD]

Your TV doesn't already have a 5V rail? Even if it somehow doesn't that's a pretty hackneyed way of getting 5V.

If you read the thread you will see that I advised Marcos to use the 5V regulator and also see Marcos' response.

[m.andrade1]

Hello All
Thank you so much for all folks for your help!
Will try supply the mod with the USB 5v 500mah, if it diesnt work will get the 5v directly from the atx power supply from the pc, as it near the tv set its easy to get the 5v, my only concern is frying the chassi, i'm very excited to test this mod, because here in brazil we have very few options to keep our arcade hobby alive, we got only 1 brand of arcade monitor Eletrocyan that stop sells long time ago, and we have to do miracles with these remaining chassis, from blooming issues till geometry issue that could't be solve, so the high expectative on that tv Philips chassis!
So on other hand here is easy to get old tvs, people still have in home watching them!

Thanks a lot
Marcos

[MarkOZLAD]

Hello All
Thank you so much for all folks for your help!
Will try supply the mod with the USB 5v 500mah, if it diesnt work will get the 5v directly from the atx power supply from the pc, as it near the tv set its easy to get the 5v, my only concern is frying the chassi, i'm very excited to test this mod, because here in brazil we have very few options to keep our arcade hobby alive, we got only 1 brand of arcade monitor Eletrocyan that stop sells long time ago, and we have to do miracles with these remaining chassis, from blooming issues till geometry issue that could't be solve, so the high expectative on that tv Philips chassis!
So on other hand here is easy to get old tvs, people still have in home watching them!

Thanks a lot
Marcos

Arcade is my passion so I hope this goes well and it can help restore some arcade games in Brazil.

[m.andrade1]

Hello Mark
So you are like me, give a look on my 2 beaulty, that i'm trying always get them better, one of them i have for about 12 years.

Always trying to anchive the graal on the image and pixel perfect so maybe can match the old good times!

Thanks
Marcos

[MarkOZLAD]

Marcos,

Looking at the following page...

http://www.geocities.ws/podernixie/htpc/cables-en.html

It seems you might need to run the H Synch and V Synch through 1000Ohm resistors before joining them to reduce the amplitude of the Sync signal from TTL levels to scart levels.

Cheers,

Mark

[m.andrade1]

Hello Mark
Wow, saved me again from ruining the tv chassis!
I saw the diagram now, it has 2 1kohms en each wire from the sync H and V, before split, i think will do just like on the diagram.
Another cool think, see this diagram is exactaly how i will supposed to do run a wire directly from the pc power supplier but this schematics have a 100ohms on the 5v wire.
Will ways that doubt becase i´m doing this directly to a "NOTUSED J281" port maybe it is already prepared to receive the signal or maybe not, who knows!
The strange thing that on this schematics shows no 75ohms on the colors wire.
Well will put those 2 1k resistors before the H+V reach the Twist, and soon will test.

Thanks again
Marcos

[MarkOZLAD]

Another cool think, see this diagram is exactaly how i will supposed to do run a wire directly from the pc power supplier but this schematics have a 100ohms on the 5v wire.

That is because the Scart specification is for 3V for RGB switching. What we are doing is very similar. We are injecting RGB into an unused port and then triggering the blanking. Most people just use 5V, however 3V would likely also work in this situation. In my experience 100Ohms isn't enough to reduce the voltage down to 3V.

It wouldn't be a bad idea to put a 1kOhm or 10kOhm potentiometer on the 5V line and reduce the resistance until the blanking is triggered.

The strange thing that on this schematics shows no 75ohms on the colors wire.

On TVs that come from the factory with Scart built in there are 75 Ohm resistors tied to ground on the inside just near the Scart port. This diagram assumes we are connecting to a TV that was built in the factory to have an RGB Scart port and therefore 75 Ohm termination built in. In your situation you have to do the 75 Ohm termination yourself..

Another cool think, see this diagram is exactaly how i will supposed to do run a wire directly from the pc power supplier but this schematics have a 100ohms on the 5v wire.
Will ways that doubt becase i´m doing this directly to a "NOTUSED J281" port maybe it is already prepared to receive the signal or maybe not, who knows!

I still think you need to get the 5V from inside the TV itself rather than from the external PSU. Otherwise there will be different grounds. I'm not sure of this though. Someone else may know if your plan will work.

EDIT: Pin 9 on the TDA4662 requires 5V. Maybe there would be a good place to get it. Datasheet here....That or Pin 12 of the Tuner as I said before.

[m.andrade1]

Hello Mark
Thanks again !
Understand about the 75ohms, will be install for sure!
1k Ohms on the Sync H and V, ready to go too!
About the 5v inject i like the Syntax idea, now i read again his answer and understand, he tell´s to wire in any one outside legs of the potenciometer no matters wich one, and them run the center pin of the potenciometer to the "F blank", he mentioned 7v till 12v, do you think will be safer to get the 5v from the power supplier, and them turning the knob until the image appears, i think i understand this way, am i correct?

Thanks
Marcos

[MarkOZLAD]

I wouldn't use the power supply at all for 5V.

I rechecked the schematics. On page 26 of the PDF (manual page 28) there are two not used connectors. J384 for the non volatile clock and J380 for the serial port. They both have 5V lines.

I would use pin 3 of the J380. Connect it to the EXT FBAL IN on J281. If you want you can put a potentiometer between so you can vary voltage as Syntax said.

[m.andrade1]

Hello Mark
Espetacular !
I saw the connector ! it´s super easy next to the mod region! will put a fast connect just like i´m using, to turn the 5v on/off just unplugin the little cable!
Give a look to the photos !

https://photos.app.goo.gl/4crnTtus6IoSuG293

Wow now i´m confident that will work !

Thanks a lot!
Marcos

[Syntax]

I wouldn't use the power supply at all for 5V.

I rechecked the schematics. On page 26 of the PDF (manual page 28) there are two not used connectors. J384 for the non volatile clock and J380 for the serial port. They both have 5V lines.

I would use pin 3 of the J380. Connect it to the EXT FBAL IN on . If you want you can put a potentiometer between so you can vary voltage as Syntax said.

Its a funny Jungle, the Blanking for external RGB is not clearly marked anywhere in the supplied schematics.

I have a funny feeling the OSD blanking pin will have 3 voltage settings ie: Off, OSD, External.
If so it may require a voltage divider but Being a Sony probably not, Panasonic is the brand that likes to keep pins high.
Either that or it requires no blanking at all for that second set of RGB inputs. Hence the interference your getting.

Almost easier to OSD hack if you cant find the correct blanking pin.

I did not look at the J281, where does its pin 3 end up on the Jungle?

[MarkOZLAD]

I wouldn't use the power supply at all for 5V.

I rechecked the schematics. On page 26 of the PDF (manual page 28) there are two not used connectors. J384 for the non volatile clock and J380 for the serial port. They both have 5V lines.

I would use pin 3 of the J380. Connect it to the EXT FBAL IN on . If you want you can put a potentiometer between so you can vary voltage as Syntax said.

Its a funny Jungle, the Blanking for external RGB is not clearly marked anywhere in the supplied schematics.

I have a funny feeling the OSD blanking pin will have 3 voltage settings ie: Off, OSD, External.
If so it may require a voltage divider but Being a Sony probably not, Panasonic is the brand that likes to keep pins high.
Either that or it requires no blanking at all for that second set of RGB inputs. Hence the interference your getting.

Almost easier to OSD hack if you cant find the correct blanking pin.

I did not look at the J281, where does its pin 3 end up on the Jungle?

Syntax, I think you're getting posts by two people mixed up....Easy to do on this crazy thread.

For Marcos' TV, the J281 pin 3 goes to the jungle's pin 26 marked F BLANK.