TV RGB mod thread

[abispac]

I'm just finished modding a Toshiba 32A33 and I'm having an issue. I'm getting blue only through the VGA cable.

I've Quadruple checked continuity between on RGB from the VGA connector to my small project board where I tie R, G, and B to ground via 75ohm resistors, and push each through a 104 cap to the other side of the board. I'm certain of good continuity between the VGA and the "in" side of this board, and continuity between the "out"side the the wires soldered to the jungle. I've ensured the wires are making good contact with the jungle pins (I soldered the wires to the legs topside) by checking continuity between the outer edge of the wire and the pins below the board. there are no shorts, I obsessively checked.

I used a 22k and 33k resistor as a voltage divider from the 5V source suggested by bratworst/others to get a 3V signal to kick the jungle into RGB mode.

Through the VGA/Scart connection I get this:



Flip the switch to put the jungle back in YUV mode and pump the 15khz vga through a vga-component transcoder, and get this through component:

.


Also, there's a dramatic shift left. i put sync through the green Y (well, it's yellow on this set but whatever, it's the green wire). Suggestions on resolving this?

Thanks in advance.


Any suggestions? Bad voltage on the blanking pin? Anything else? I'm at a loss at the moment.

i had a similar problem once and it was a problem with my cable.

[benyamin39]

Can you add a pullup resistor to the color channels to bring the swing up?

Thx for the suggestion. I don't know how exactly a pull-up resistor configuration works. I guess I need to work from the 5v supply to swing up the voltage with a resistor and maybe add-on with rgb signal. Looking at the documentation on the web, often a pull up resistor is associated with a transistor. What is the general arrangement of a pull up resistor in this case? Thx for ur help

I have setup a second op amp to add the voltage following the schmeatic below.


The results are better. I should be able to get there.


Note that I also tried to add the 3.3V and0-0.7Vpp straight to the THS7315. It works, color gradient improves but not as much as with the schematic described above.

I am left with 2 issues
1. I used a generic quad amp NTE987. It generates a lot of noise. I will try with an AD8054 that is adapted for video signal processing. Anybody used that one?

2. More annyoing : When I disconnect the red cable the voltage input on the second op amp jump and I get redish screen. the voltage on the input of the second op amp goes up and the output voltage reach 2.5V instead of 1.6V. I believe it is due to the relative impedance of the 3.3V line and the 0-3.6Vpp line. Would a diode do the job?



I feel that those issues are getting quite complex, and maybe shmups rgb mod is not the best avenue to discuss it. Anybody knows a forum where more generic video processing and electronics are discussed, for which those questions are addressed?

Thx

[Osirus]

[
CRT Emudriver has support for Composite Sync.

huh. crazy.

Still though, it's a real pain in the ass to setup.

It kind of is. I prefer to build a sync combiner into my RGB mods and use RGBHV as my input.

[vol.2]

I have setup a second op amp to add the voltage following the schmeatic below.

Spoiler

I didn't mention this at first because I wanted you to follow through with Syntax's suggestion first, but I noticed in your earlier post that you had the op-amp setup in inverted mode. I'm too lazy to read through this second schematic of yours, but make sure you are using the Non Inverted schematic from the op-amp datasheet.

Generally speaking, I've noticed that op amp datasheets often give the primary example circuit in the inverted operation because they are often used for audio, and it doesn't matter in audio if it's inverted or not (because you're just moving the speaker cone back and forth).

[cyborc]

Also, there's a dramatic shift left. i put sync through the green Y (well, it's yellow on this set but whatever, it's the green wire). Suggestions on resolving this?

The component green (Y) input on this TV also functions as a composite input. if you plug any random RCA cables into the red and blue inputs, it will activate component mode, and bypass the comb filter that's used when this input is in composite mode, which is causing your picture shift issue. There's probably a cleaner way to do this internally with a switch but that's the quick and dirty method.

[Bratwurst]

The component green (Y) input on this TV also functions as a composite input. if you plug any random RCA cables into the red and blue inputs, it will activate component mode, and bypass the comb filter that's used when this input is in composite mode, which is causing your picture shift issue. There's probably a cleaner way to do this internally with a switch but that's the quick and dirty method.

I'll have to give this a try, when did you discover this?

[MarkOZLAD]

> I have not found the mix method eplained

With the mix method we mix the OSD and external RGB into the same circuit at the same time and use a resistor on each RGB line to create a voltage divider so that the OSD RGB has the correct voltage level.

...as opposed to the OSD Snip method where you implement the mod the way a general assistant at a public school might do electronics.

[abispac]

> I have not found the mix method eplained

With the mix method we mix the OSD and external RGB into the same circuit at the same time and use a resistor on each RGB line to create a voltage divider so that the OSD RGB has the correct voltage level.

...as opposed to the OSD Snip method where you implement the mod the way a general assistant at a public school might do electronics.

Thank you kind Markkoslad, im reading alot, to get the hang of it, right now im working on a real arcade monitor, but as soon as i finish this project, ill get my hads dirty on a tv rgb mod again, i got this new 13 set, but i suspect is digital rgb, if im not mistaken, digital rgb give 0.1 v while analog give 7.0v? im stll learning, but ill get there...thanks again

[Osirus]

> I have not found the mix method eplained

With the mix method we mix the OSD and external RGB into the same circuit at the same time and use a resistor on each RGB line to create a voltage divider so that the OSD RGB has the correct voltage level.

...as opposed to the OSD Snip method where you implement the mod the way a general assistant at a public school might do electronics.

Thank you kind Markkoslad, im reading alot, to get the hang of it, right now im working on a real arcade monitor, but as soon as i finish this project, ill get my hads dirty on a tv rgb mod again, i got this new 13 set, but i suspect is digital rgb, if im not mistaken, digital rgb give 0.1 v while analog give 7.0v? im stll learning, but ill get there...thanks again

Typical analog RGB is 0.7Vpp. Digital is TTL voltage.

[abispac]

> I have not found the mix method eplained

With the mix method we mix the OSD and external RGB into the same circuit at the same time and use a resistor on each RGB line to create a voltage divider so that the OSD RGB has the correct voltage level.

...as opposed to the OSD Snip method where you implement the mod the way a general assistant at a public school might do electronics.

Thank you kind Markkoslad, im reading alot, to get the hang of it, right now im working on a real arcade monitor, but as soon as i finish this project, ill get my hads dirty on a tv rgb mod again, i got this new 13 set, but i suspect is digital rgb, if im not mistaken, digital rgb give 0.1 v while analog give 7.0v? im stll learning, but ill get there...thanks again

Typical analog RGB is 0.7Vpp. Digital is TTL voltage.

Thank you kind, see its not that hard to actually correct a newbie that might have a little bit of knowledge so it can start learning, now that im understanding a bit more, i can even help some folks in the future, im gathering as much information as i can, thanks again.

[abispac]

look what i scored for 10 bucks, it should be just a matter of following instruction on here https://tinkerplunk.wordpress.com/spongebob-tv-rgb-mod/, hopefully its the same model.

[Mantis128]

Has anyone had luck modding an older TV, pre-1993? Or is it easier to just stick to mid-90's/early 2000's TV's?

[abispac]

So the spongebob tv i got has some problems , that i hope it would be just a cap, so im gonna tackle that first before attempting the rgb mod, so i dont get confused in case something goes wrong. Also im going to open a new topic on this one so that we have 2 places to look for instructions once i finish the mod

Spoiler

[vol.2]

So the spongebob tv i got has some problems , that i hope it would be just a cap.

It looks like a vertical linearity issue. Very common with old sets and probably the caps in the VERT section. You'll need a schematic for sure though. Make sure you get everything in the VERT section because a bad cap there can blow the IC in certain sets.

Also, you might consider putting a photo like that in a spoiler so it doesn't fill up the thread. You can also use imgur or whatever to resize your pictures so they aren't so huge.

[abispac]

So the spongebob tv i got has some problems , that i hope it would be just a cap.

It looks like a vertical linearity issue. Very common with old sets and probably the caps in the VERT section. You'll need a schematic for sure though. Make sure you get everything in the VERT section because a bad cap there can blow the IC in certain sets.

Also, you might consider putting a photo like that in a spoiler so it doesn't fill up the thread. You can also use imgur or whatever to resize your pictures so they aren't so huge.

There is one big cap blown, 220uf 200v if i remember right, i dont have it in front of me right now. There are no model stickers nor any information on the chassis itself, i have identify both chips, as this chassis is not the same as the original spongebob mod, so tomorrow ill start manualy tracing lines and i need to get me another multimeter to look at the values of the resistors and all the info i need. Thanks alot for pointing me for the image size. Ill update this tomorrow.

[bigthumbs2511]

Looking for any info on a Mitsubishi CS-40707. Has anyone had experience with Mitsubishi sets? Or Mitsubishi service manuals? Can’t seem to find any.

EDIT: Service Manual https://drive.google.com/file/d/1EtSrfz ... sp=sharing

Chroma Chip Data Sheet https://pdf1.alldatasheet.com/datasheet ... asheet.pdf

I’m not sure where exactly I should inject my RGB :/

[MarkOZLAD]

Looking for any info on a Mitsubishi CS-40707. Has anyone had experience with Mitsubishi sets? Or Mitsubishi service manuals? Can’t seem to find any.

EDIT: Service Manual https://drive.google.com/file/d/1EtSrfz ... sp=sharing

Chroma Chip Data Sheet https://pdf1.alldatasheet.com/datasheet ... asheet.pdf

I’m not sure where exactly I should inject my RGB :/

Had a quick look at the service manual, IC6 E01 looks interesting.

[bigthumbs2511]

Had a quick look at the service manual, IC6 E01 looks interesting.

Thanks! This one here? https://imgur.com/gallery/iu5QJJm

[abispac]

Dumb question, does the tv has to be on the video input to be able to display the rgb contnt, or it should display it on any channel?

[vol.2]

Dumb question, does the tv has to be on the video input to be able to display the rgb contnt, or it should display it on any channel?

Generally, should be on the video input. Most mods are using the Luma input from the video for the sync, though I didn't follow exactly what you did for your mod.

[abispac]

Dumb question, does the tv has to be on the video input to be able to display the rgb contnt, or it should display it on any channel?

Generally, should be on the video input. Most mods are using the Luma input from the video for the sync, though I didn't follow exactly what you did for your mod.

I decide to open a new topic for this spongebob tv mod as is a diferent model, i would like people to follow up in the future, im at a point where it seems is working but i need to change the input, but since i dont have the original remote, ima have to find a universal remote that works in order to change the input, i read somewhere else that GE remotes work with this tv, so im gonna have to wait to see if it fully works
viewtopic.php?f=6&t=68317

[francoisadt]

Hi everyone

No one has yet respond to my questions below posted 23 March 2021 but have responded to other users posts, posted msgs after my post?
One problem is moderation takes time so by the time my post get approved it is date wise way back in the queue. Can mods take away my restriction so that my post do show top of the queue when posted?

See my original questions in original post quoted below, let me highlight two most important questions

In essence I want to connect RGBS direct feed from arcade PCB, 5pin molex that normally goes into arcafe monitor chassis for the tube, to a TV CRT monitor chassis board that do have on the board a place to have a chip/adaptor socket to feed Red Green Blue from old devices. I do not have the chip, the purpose of tge chip explaned below bur it only do switch between AV feed comping from external socket or the three RGB feed feed as a secondary feed. I do not have any av feed just rgb from srcade pcb.

Shorter version of one of my question:
Can I just link my 5 wires one by one to each connection point on the TV CRT chassis board which contain a socket which allowfor external rgbs feed. see below my explanation in original feed.

Second question:
How do I sent GND and Sync from pcb to the TV CRT AV sicket? Can I just wring the endpoints togehthet and solder it on the av input line or an sync line that goes into the CPU? Original post got link to the schematic

Have a wonderful day forum mbrs

regards
Francois du Toit

I do have an LG CRT which I want to hook into by linking the RGB output feed from my Pac-Man PCB dierctly to this TV CRT.



There is a RGB switch holes which are indicated as RGB external switch. The actual RGB CIRCUIT switch IC is not installed but the lines
runs through from LEFT to RIGHT. So if I hookup the RGB lines to the OUTPUT of the RGB switch circuit block
then the R(OUT) , G(OUT) and B(OUT) will feed the jungle chip as input.

See attached diagram :

I have read previous post below and I am not understanding what is written below.

Sorry, long time lurker on this forum and I finally needed to post. I recently picked up a Sharp 27DV-S100 TV. Yes, it is a VCR/DVD combo system (and the DVD does not work), but the picture is extremely nice. After looking it over, I am trying to figure out if it is possible to RGB mod it. From everything I can find, I believe the answer is yes, but I wanted to ask someone more knowledgeable than myself to see if I am not thinking this is going to be easier than it looks.

External, everything is composite. Internally, the VCR and DVD are connected essentially through S-Video (just not using the port). However, everything is converted to RGB for the CRT. In the service manual, I found the diagram for these connections go through a single chip:


I also found the complete pin diagram for the chip:


To me that, looks like there are RGB input pins on 32-34 which are currently just going to ground (through either caps or resistors). Anyone see this chip before and know how difficult it would be to mod? I am thinking it is just a matter of wiring up an external connection to those grounded pins and and send the proper signal to tell the chip to use the RGB inputs as the source. Again, am I missing something that would make that impossible?

Here's the datasheet for that jungle IC. http://www.datasheetcatalog.com/datashe ... 76AN.shtml

You should be able to insert your RGB signal on pins 33-35 and blanking on pin 32. (0.75v) You will need to remove those capacitors to ground on the R, G and B lines and add your own capacitors in series with your external RGB signal. (0.1uf most likely) Overall, a relatively easy job. You lucked out! In my experience, Sharp CRTs look great when RGB modded.

Question:
=======
So I will do the same hack mentioned above but on pin 16, 13, 11 on the diagram block where the RGB Circuit switch called TEAC5114, suppose to be.
See red circled spaces in my attached diagrams here in this post?

Question:
=======
What is mean by "blanking on pin 32"? What is one need to do by blanking? What wire is a blank? Is that ground from the external RGb feed?

Question:
=========
What is mean by removing capacitors, adding own capacitors? Why is this needed? Do I have capasitors in my shematic on RGB flow?

It may be possible to cut the ground plane traces but your plan is solid

I would just pump Sync and Audio through the AV port. Can solder underneath them if you want, (I generally break them out into RCA ports and run cables, but I'm weird.) If you need to trigger stereo you can by putting a cut RCA plug in the right channel. I have never soldered sync internally. Not sure why you think there needs to be a diode.

You should only need a switch for the RGB blanking. With blanking voltage disabled the RGB input won't do anything. If you will have a blanking voltage from your Scart/RGB cable you can use that to switch the RGB on, that way the TV enables RGB when you turn the console on.

Question:
=-======
To get sync from my Pac-Man PCB. Which nr on my schematic must I send/link sync to from RGB 5pin connector from Pac-Man PCB, white wire, I think it is a composite/combined sync from Pac-Man PCB?

Question:
========
How can one sent sync to AV port from white wire (sync) from Pac-man 5pin molex , balck (ground)? What is meant by "Sync and Audio through the AV port"?
Can I just combined white threaded wire and the ground and toe it together by hand and stick it into AV port or solder it to which SYNC line on my schematic
of the jungle chip?


Question:
"You should only need a switch for the RGB blanking. With blanking voltage disabled the RGB input won't do anything"
What is meant by switch here? RGB blanking? In my RGB Curcuit switch there is not chip so I just want to solder the RGB and sync on the RGB output
of RGB witch which led to the Jungle chip RGB input?

Question:
=======
On the RGB Circuot switch block diagram, there is GROUND (labelled as nr 2), and VCC (Voltage) as nr 14.
Must I wire RGB ground from Pac-man PCB to this nr 2?
Must I wire volatge from Pac-Man PCB (5 volt) red wire to nr 14?

How do I get ground from Pac-Man PCb to this chassis? Must the same power that switch on the TV (main plug 220V) feed
join somewhere the ground of the Pac-MAN PCB? into this chassis? If not will that stop any picture of showing?
So is any ground wire just ground or must the same ground feed coming RGB 5pin Pac-man PCB, also be the same
ground that feed the ground for SYNC generate the picture from jungle chip? So do I need GND from Pac-Man PCB feed
into Jungle chip somewhere?

Question:
=========
Where must I sent SYNC in (white wire) from PAc-man PCB SYNC to Jungle chip or RGB circuit switch output?
To be safe then: Please explain to me how to sent SYNC from PAc-man PCb to AV port and also wire another SYNC wire
to chassis - where on this block diagram?


I do have an LG CRT which I want to hoo ... sp=sharing

LG RGB Circuit Switch Link:
https://drive.google.com/file/d/1Wv_4N5 ... sp=sharing

[Osirus]

I have very little experience with arcade boards, but I believe a Pac-man PCB would use HV sync, so you would need a sync combiner to make it composite sync, and then run that composite sync into the Video-In or Y-In on your TV.

All your GND connections on your inputs can be connected together and connected to any GND point on your chassis (that isn't on the hot side).

[vol.2]

No one has yet respond to my questions below posted 23 March 2021 but have responded to other users posts, posted msgs after my post?

I think the issue is that your question is out-of-scope for this thread. Yes, there have been other people with arcade-related questions, but that has nothing to do with RGB modding a consumer TV. That's the next step beyond.

You'd probably do better off making your own thread in the Hardware section so people who know about arcade boards actually see it. Also, this thread is hard enough to sort through already, so it doesn't help to have a bunch of tangential questions.

[Syntax]

Its not that, he's questions are ignored because they are so basic and self explanatory.

[MarkOZLAD]

For arcade PCBs, if they are outputting Jamma RGBS you will want to do a standard RGB mod on the TV, you then attenuate the Jamma RGB so that the TV receives scart levels of RGB, this can be done using potentiometers wired as variable resistors or using RGB amps as buffers you see in superguns. For sync generally a resistor of around 500 to 1000 ohm on the line and then into the AV port.

[Gonzalo]

How do i get rid of the ghosting and shades from the left of the screen? Is that some kind of interference and wires have to be shielded?



Image quality is very good. Picture doesnt make it justice.

[MarkOZLAD]

How do i get rid of the ghosting and shades from the left of the screen? Is that some kind of interference and wires have to be shielded?



Image quality is very good. Picture doesnt make it justice.

You’ve got vertical jailbars. Try googling that and see if you can find anything.

[DarthMotzkus]

Hi!
I own a RVL-001 Black American NTSC Wii model, and my question is:
If i change the Region and Video mode to PAL/E with the Wii Mod Lite homebrew app, did I'll get the same quality RGB than a native PAL/E Wii console or they are different in hardware speaking? Some people talk about the NTSC Wii still output a poor composite signal even after changed the region and video mode to PAL on RGB, and i get a bit confused and don't know if it's true.

[vol.2]

How do i get rid of the ghosting and shades from the left of the screen? Is that some kind of interference and wires have to be shielded?

That looks like ringing getting into scan time somehow. You would first have to determine if it's present in the video signal or not. If it's from the video signal, your TV is okay and it's coming from your signal.


However, I think it's the TV. My guess just looking at it is that it's the ripple from the flyback leaking into the ground plane and something somewhere isn't filtering it out properly.

IAC, I've had similar issues and I was never able to fix them. I'm actively working on one set that I've exhausted almost everything I can think of, including (but not limited to) isolating the heater from the cathode, changing all the caps in the deflection circuitry, adding extra filtering to all of the power supply rails, and filtering all the AC out of the video signal.

Maybe you will have better luck than I do, but it might be hopeless.