TV RGB mod thread

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OnlyBrian
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Re: TV RGB mod thread

Post by OnlyBrian »

KPackratt2k wrote: Yes, that should work fine.
How about a positive update in the meantime? Figured we're overdue.
https://imgur.com/a/hMUmSN8

It works great! The muxing is perfect. The image is crystal clear.

I am still plagued by that darn interference however. I wonder if I damaged the jungle chip somehow.

EDIT:

https://www.youtube.com/shorts/2DOA0f2yeVk

See how it appears in OSD during channel swap? I wonder if I did really damage the OSD.
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RVA818XLAY
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Re: TV RGB mod thread

Post by RVA818XLAY »

OnlyBrian wrote: See how it appears in OSD during channel swap? I wonder if I did really damage the OSD.
If you **really** wanted to check you could revert back to factory standard and see if the interference is still there
tongshadow
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Re: TV RGB mod thread

Post by tongshadow »

OnlyBrian wrote: I am a little confused about the Blanking switch, and what I need to add to make it work with an on off switch. Should I grab a 3 prong or 2 prong?
Like I said, very new and this is the last point of contention before I embark. I'm also not sure if the Resistor value for the OSD blanking is actually 6.8k.
I thought the point of the MUX RGB mod was to avoid the use of a switch altogether. Am I missing something?
OnlyBrian
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Re: TV RGB mod thread

Post by OnlyBrian »

Well, I'm out of ideas.

I lowered the Ground Resistor to 75 Ohms from 180 with no change in picture quality.
I lowered the RCA Jack Resistor to 1.3k from 1.6k with no change in picture quality.
I removed R802 (the blanking line ground resistor near the jungle chip) since I forgot to, hoping that would resolve it.

This line simply will not disappear.
I wonder if there's a service menu option I'm missing. Well, I guess all of them since the service menu doesn't work either. Anybody know how to enter the service menu on a Sharp/Mitsubishi TV? The one listed in the manual doesn't work.
tongshadow wrote: I thought the point of the MUX RGB mod was to avoid the use of a switch altogether. Am I missing something?
I think it's so the OSD appears in RGB Mode, but if you need composite, you can easily switch back. At least, that was my interpretation.
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matt
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Location: Honolulu, Hawaii

Re: TV RGB mod thread

Post by matt »

tongshadow wrote: I thought the point of the MUX RGB mod was to avoid the use of a switch altogether. Am I missing something?
The point of the Mux mod is to preserve the OSD. Some sort of switching voltage is still required to enable the RGB input. There are good reasons for using a physical switch in this case, although some people prefer to draw it from the console's video port instead.
moldov
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Re: TV RGB mod thread

Post by moldov »

I tried to modify SONY KV-G14M1. I didn't find schematics for that particular model but schematics for KV-G21 was looking similar, so I took it as a reference. I found RGB lines on the socket CN106 (header was not soldered but connecor names were written there) terminated them with 75 ohms, BLK I also terminated (however I removed that termination later).

Image

I got very dark picture and started to check schematics. I found R327, R328, R329 terminating RGB lines and their resistanse was 0 Ohms.

Image

So I guess SONY just disabled RGB input with those resistors. I removed them and got very clear RGB picture.

Please be aware about such 0 Ohms terminations.
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Syntax
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Re: TV RGB mod thread

Post by Syntax »

Most floating inputs get grounded to avoid internal oscillation.
Same goes for things like the LPF on a THS7374 amp.

Some chips don't require it, best to check.
tongshadow
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Re: TV RGB mod thread

Post by tongshadow »

I've been hearing about people frying their chips due to accidental static electricity discharge through the switch. Is there a proper way to ground the switch or is using a plastic switch the only safer option?
PressLeft
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Joined: Wed Feb 17, 2021 3:30 pm

Re: TV RGB mod thread

Post by PressLeft »

Just picked up a Sony KV-32S45, and I’ve got a KV-32S26 lined up to pick up in a couple weeks. I’ve been reading about this thread and the component thread and finding that since they’re both Chassis AA-2D I can definitely do an RGB mod, and possibly a YUV mod. One of them will be replacing my JVC AV-27230s as my main CRT. Right now I’ve got a 3-in component switcher and a 4-in s-video switcher and a composite in being used. If i could, I’d love to keep that setup going and maybe add RGB as a single input for my MiSTer. This would mean adding *both* YUV and RGB to this set, which is apparently possible on similar sets.

If successful, this would be my first RGB mod, but since they’re both the same chassis I would be able to only have to learn what I’m doing once. I’m an experienced modder for consoles and other soldering projects, but i really want to make sure I get this right.

I’ve got links to other people’s work for reference here:
https://imgur.com/a/BjLmET0
https://imgur.com/gallery/86MwRVT

And the service manual here:
https://www.manualslib.com/manual/15961 ... 32s40.html

Given that these are pretty well documented, I’m pretty confident I can make it happen. Anyone got any suggestions before I plan out my work? Am i missing something important about this like i can’t use both YUV and RGB and i have to pick? Will I be unable to use s-video and RGB without swapping cables? Anything like that?
hidden0
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Re: TV RGB mod thread

Post by hidden0 »

moldov wrote:I tried to modify SONY KV-G14M1. I didn't find schematics for that particular model but schematics for KV-G21 was looking similar, so I took it as a reference. I found RGB lines on the socket CN106 (header was not soldered but connecor names were written there) terminated them with 75 ohms, BLK I also terminated (however I removed that termination later).

Image

I got very dark picture and started to check schematics. I found R327, R328, R329 terminating RGB lines and their resistanse was 0 Ohms.

Image

So I guess SONY just disabled RGB input with those resistors. I removed them and got very clear RGB picture.

Please be aware about such 0 Ohms terminations.
Exactly what i was searching for ‘ i have j14 but similar board and 0 ohm resistors.

Just an overview if i want to use scart

I use direct lines from RGB from unpopulated cn106 ‘remove 0 ohm resistors’ that blk line from the same cn106 and add 5v from somewhere on the board and use the gnd from anywhere else.

And for sync i need to take composite
And use a switch to switch between osd and rgb?

Is that it or do i need to do anything else.

Or use any resistor somewhere.
hidden0
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Re: TV RGB mod thread

Post by hidden0 »

moldov wrote:I tried to modify SONY KV-G14M1. I didn't find schematics for that particular model but schematics for KV-G21 was looking similar, so I took it as a reference. I found RGB lines on the socket CN106 (header was not soldered but connecor names were written there) terminated them with 75 ohms, BLK I also terminated (however I removed that termination later).

Image

I got very dark picture and started to check schematics. I found R327, R328, R329 terminating RGB lines and their resistanse was 0 Ohms.

Image

So I guess SONY just disabled RGB input with those resistors. I removed them and got very clear RGB picture.

Please be aware about such 0 Ohms terminations.
Can we use 75ohm smd resistors on the place we removed the 0 ohm resistors ‘ should be easier solution ?
Pencilman
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Joined: Thu Aug 18, 2022 7:24 pm

Re: TV RGB mod thread

Post by Pencilman »

I just picked up a Daewoo DMQ-1446 for free. It has composite input so I was hopping to try my first mod on it. Well as my luck goes I can't find the service manual for the dang thing anywhere. I opened it up, discharged it and started poking around. I can't find any info on the controller chip, an M34300-230SP. I did find out the jungle chip is a Toshiba TA8659AN. It has RGB input... But in this case the pins are not connected to anything. I did notice that the RGB outputs go to the AN5862K (ANALOG SWITCH ICS FOR RGB INTERFACE) and that goes directly to the tube PCB. Am I to take it I'm in luck?

If I understood the mod correctly I only need to connect my inputs to the RGB pins with the 1k diodes in series and 75ohm resistors in parallel and I'm set? But what about the BLK line? I can't seem to locate it on the TA8659AN or the M34300-230SP (since I can't locate the datasheet).

Image

Image

Image
tongshadow
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Re: TV RGB mod thread

Post by tongshadow »

One more (somewhat) successful RGB Mod, this time on a 15" Philips Stereo set (14GX1619). Despite being only 15", it's packed with 2 inputs, 1 set of outputs and a pair of 4W speakers, quite powerful for its size. And the best part: a good old curved screen. I have to say: these older sets have outstanding potential. And while I dont usually recommend getting these sets just for RGB modding (just get a set with component inputs and use RGB2COMP), it's well worth the trouble. Just look at these pictures comparing RGB vs Composite.

Megaman X
https://i.imgur.com/XdqGv24.jpeg
https://i.imgur.com/943lnLE.jpeg

Yoshi's Island
https://i.imgur.com/jAl9bgj.jpeg
https://i.imgur.com/tyyeZlP.jpeg

Super Castlevania IV
https://i.imgur.com/pF2C7RD.jpeg
https://i.imgur.com/HkrdNYY.jpeg

Street Fighter II: Turbo - Just look at the health bar
https://i.imgur.com/vMb4B9x.jpeg
https://i.imgur.com/ou2s8WX.jpeg

Yea... I'm sorry, composite fetishists, but RGB is the clear winner here. The pictures actually make composite look better than it really is because the dot-crawling, noise, and improper red levels cant be captured easily. Sure, composite on a CRT still beats any modern panel using the same type of signal, but RGB is a huge step-up.

Now let's about the more technical side of things, I'll be brief. It uses a TDA 8374A jungle chip that requires 3V max, 0.9V min for RGB blanking. This set didnt have 3V lines so I just used the 5V line, attached it to unpopulated parts of the board and created a voltage divider using 2 resistors so I could get 2.5V, like so (notice the purple wire soldered to the resistors):
https://i.imgur.com/KEV6kqf.jpeg

Because I detest butchering the case, I decided to use the existing RCA AV outputs as inputs for RGB. Just remove the components, in this case resistors, to isolate the inputs. It also makes it that much easier and less messy to connect the wires and resistors to the RGB path.
https://i.imgur.com/sPgEC7S.jpeg
https://i.imgur.com/ZYLP40n.jpeg
https://i.imgur.com/ELip1mr.jpeg

It's worth mentioning I used the mux method by adding diodes to the OSD lines, which was easy to do because the OSD RGB path was conveniently populated with jumpers, so I just had to replace them with diodes.

And finally, the switch. It's a 3-way switch wired as: 2.5V on pin 1, wire to the chip on pin 2 (common) and wire from the micom on pin 3.
https://i.imgur.com/sFXbCX9.jpeg
The installation was very simple as well because this TV originally had handles, and the empty space left by its absence enabled me to easily attach the switch into the top.
https://i.imgur.com/cKr7caF.jpeg

Everything works well except for the OSD that is very dim but still visible. This could be due the way the chip handles transparencies/half-tones, however I wont try to fix it because we only fiddle with the settings once.

Overall, despite being a TV set from 1996 it still looks very good. There's no noticeable smearing, the luminance remains strong, the video-processing is top notch and it's a curved screen with near-perfect geometry. The Stereo sound also enhances the gaming experience even further, no need to use external speakers. I'm sure that at the time this was a top of the line set, and now thanks to the RGB mod its fullest potential can be finally realized.

https://i.imgur.com/T3ckQS0.jpeg
hidden0
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Re: TV RGB mod thread

Post by hidden0 »

MarkOZLAD wrote:The fact that the picture controls do nothing has no bearing on whether it’s a Mux.

If you look at block diagrams of these jungles you’ll see that the external RGB bypasses all those controls. It’s pretty much just straight to an amplification section.
I completed the RGB mod by reading your posts and work helped me alot
Model sony kv-j14L BG-2S chassis all went well.
Used the 75ohm resistors / with rgb lines showed good on multimeter / blanking line to 2.5v

It worked just fine now the issue is vertical white bands showing on RGB .

Image

https://imgur.com/a/CROUTZd

But with composite its fine and normal.

Searched everywhere couldn’t find any solution.
Seth562
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Re: KV-27S15

Post by Seth562 »

Hello everyone, I have been lurking here for the past few weeks, trying to absorb what I can before making a post. I received a KV-27S15 from a person from Craigslist. Funny story, as he was bringing down the tv from the top floor, he dropped it and all the plastic casing broke. So what is left is the board and screen. Good opportunity to do a RGB MOD.

Image

Here's a diagram of the KV-27S15. If I inject RGB wires before the 220 OHM resistors and terminate with 75 OHM resistors I should be good?
KPackratt2k
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Re: TV RGB mod thread

Post by KPackratt2k »

hidden0 wrote:
MarkOZLAD wrote:The fact that the picture controls do nothing has no bearing on whether it’s a Mux.

If you look at block diagrams of these jungles you’ll see that the external RGB bypasses all those controls. It’s pretty much just straight to an amplification section.
I completed the RGB mod by reading your posts and work helped me alot
Model sony kv-j14L BG-2S chassis all went well.
Used the 75ohm resistors / with rgb lines showed good on multimeter / blanking line to 2.5v

It worked just fine now the issue is vertical white bands showing on RGB .

Image

https://imgur.com/a/CROUTZd

But with composite its fine and normal.

Searched everywhere couldn’t find any solution.
It looks like you're encountering vertical jailbars. That's a common problem with CRT TVs, especially Sony Trinitrons. You can fix it by recapping the vertical section, use low ESR capacitors as they are under a lot of stress.

If that doesn't solve the problem, try replacing your RGB wires with shielded wire.
tongshadow
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Re: TV RGB mod thread

Post by tongshadow »

Has anyone here ever tried to RGB (or composite) mod old TVs with UHF/VHF outputs? Someone said it should be avoided due to most of them being a hot chassis.
KPackratt2k
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Re: TV RGB mod thread

Post by KPackratt2k »

tongshadow wrote:Has anyone here ever tried to RGB (or composite) mod old TVs with UHF/VHF outputs? Someone said it should be avoided due to most of them being a hot chassis.
I've managed to mod an RF-only RCA E13309 TV for both RGB and Composite.

viewtopic.php?f=6&t=56155&p=1451968#p1451968
https://www.youtube.com/watch?v=fFKV3aBQ5Xg

TL;DR: The composite mod was easy as I was able to find an EEPROM dump from a model with the same chassis, but with AV inputs, so it was as simple as flashing the EEPROM, soldering a header, and wiring my jacks to it. As for RGB, it wasn't quite as easy as I've found out the hard way that the jungle chip expected a 1.0vp-p signal rather than the usual 0.7vp-p, so I had to try different resistor combinations until I could find one that worked correctly.

This chassis used a modern switching mode power supply, so there were no concerns around it being a hot chassis. This made sense because there were variants of this chassis that had AV inputs as I've already mentioned. I once had an older GE TV that I was hoping to mod, but unfortunately that turned out to be a hot chassis with Digital TTL RGB for its OSD. If you're modding a hot chassis TV, an isolation transformer is a must-have. Otherwise you could short out the TV or risk getting shocked by your modded input jacks.
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matt
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Re: TV RGB mod thread

Post by matt »

KPackratt2k wrote:It looks like you're encountering vertical jailbars. That's a common problem with CRT TVs, especially Sony Trinitrons. You can fix it by recapping the vertical section, use low ESR capacitors as they are under a lot of stress.

If that doesn't solve the problem, try replacing your RGB wires with shielded wire.
Jailbars aren't from the vertical section. It's usually caused by bad filter capacitors on the B+ line. If those lines were present before the mod, that would be the place to look.

Although, I recall someone else who found that using the wrong blanking voltage to the jungle chip was causing similar jailbars.
tongshadow
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Re: TV RGB mod thread

Post by tongshadow »

KPackratt2k wrote:
tongshadow wrote:Has anyone here ever tried to RGB (or composite) mod old TVs with UHF/VHF outputs? Someone said it should be avoided due to most of them being a hot chassis.
I've managed to mod an RF-only RCA E13309 TV for both RGB and Composite.

viewtopic.php?f=6&t=56155&p=1451968#p1451968
https://www.youtube.com/watch?v=fFKV3aBQ5Xg

TL;DR: The composite mod was easy as I was able to find an EEPROM dump from a model with the same chassis, but with AV inputs, so it was as simple as flashing the EEPROM, soldering a header, and wiring my jacks to it. As for RGB, it wasn't quite as easy as I've found out the hard way that the jungle chip expected a 1.0vp-p signal rather than the usual 0.7vp-p, so I had to try different resistor combinations until I could find one that worked correctly.

This chassis used a modern switching mode power supply, so there were no concerns around it being a hot chassis. This made sense because there were variants of this chassis that had AV inputs as I've already mentioned. I once had an older GE TV that I was hoping to mod, but unfortunately that turned out to be a hot chassis with Digital TTL RGB for its OSD. If you're modding a hot chassis TV, an isolation transformer is a must-have. Otherwise you could short out the TV or risk getting shocked by your modded input jacks.
This is what the RCA inputs look like on the chassis I'm trying to modify. Those are optocouplers meant to isolate the AV inputs.

Image
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matt
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Re: TV RGB mod thread

Post by matt »

Yeah, in some cases the designers chose to isolate only the A/V inputs rather than the whole chassis. Modifying a TV like that is not safe, unless you use an isolation transformer (there's a reason why they went to the trouble of adding optocouplers to the input jacks).
hidden0
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Re: TV RGB mod thread

Post by hidden0 »

matt wrote:
KPackratt2k wrote:It looks like you're encountering vertical jailbars. That's a common problem with CRT TVs, especially Sony Trinitrons. You can fix it by recapping the vertical section, use low ESR capacitors as they are under a lot of stress.

If that doesn't solve the problem, try replacing your RGB wires with shielded wire.
Jailbars aren't from the vertical section. It's usually caused by bad filter capacitors on the B+ line. If those lines were present before the mod, that would be the place to look.

Although, I recall someone else who found that using the wrong blanking voltage to the jungle chip was causing similar jailbars.
The jailbars doesn’t appear when using composite only when inputting the rgb even without the rgb cables from the consoles plugged in. And on blk line i am using 75+75 ohm resistor one on with blk line and one termination to the ground to devide the voltage as suggested on many videos.
tongshadow
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Re: TV RGB mod thread

Post by tongshadow »

Sad to report that I wasnt able to RGB mod a security monitor using the VDP 3130Y jungle chip. Even though I managed to inject RGB, the color balance was totally out of whack, and the brightness/contrast settings werent affecting the picture at all. Also, it was severely off center. It seems this chip uses separate settings for RGB and since I couldnt even find a service manual for the monitor, it was impossible to improve the picture.
RetroSpark
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Re: TV RGB mod thread

Post by RetroSpark »

I'm currently working on a Sony Trinitron KV-XJ29M31 (BG3R chassis) - I think a few people here have modded the same or a similar model.

Is it normal for the picture via RGB to be brighter than via composite?

I get a good-quality picture by injecting RGB via the Teletext connector, but the image is too bright. I can compensate by adjusting Picture & Brightness in the TV's menu, but I'd rather not have to - it makes it awkward to switch between RGB and composite.

This doesn't seem to be caused by an issue with the external R/G/B signals, but with blanking - even with no external R/G/B, as soon as I enable blanking the whole screen brightens from black to dark grey. I can think of two possible causes for this:

1. Maybe my blanking connection is wrong? I'm using a 1200 ohm resistor to connect the Teletext "BLK" pin to its "7V" pin - given the existing 470 ohm resistor to ground, this sets "BLK" to 2.25 V. I don't think the 7V supply is regulated - could this be a problem?

2. The OSD uses the same R/G/B lines as the Teletext connector, so the unexpected brightness could be coming from the OSD. If so, do I have to disconnect the OSD R/G/B to fix the issue, or is there an easier way to get the brightness via RGB looking closer to composite?
Pencilman
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Re: TV RGB mod thread

Post by Pencilman »

So... I managed to source a schematic for my Daewoo TV and that includes the controller chip. Can anyone help identify the blanking signal? As I assumed the RGB input pins are traced to GND. Is this TV even moddable?

https://elektrotanya.com/daewoo_chassis ... nload.html
tongshadow
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Re: TV RGB mod thread

Post by tongshadow »

How old is this TV? Looks like a hot chassis to me.
Zronium
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Re: TV RGB mod thread

Post by Zronium »

I'm new to this stuff and a bit lost. I'm trying to add YPbPr to a KV20FS12 BA-5. I can't seem to get sync. I'm almost certainly missing a step, or did something incorrectly, finding info for this is hard. No S-Video on this model. I've run sync into CVBS2 for video 2 to no result, also tried running it into Y1 with enabling s-video in the service menu (with and without a 10uF Cap. One random post suggested it. the cap was polarized, not sure if that matters, or I put it the wrong direction) Any help or suggestions would be appreciated.


I made a 2 second diagram of what I've done so far. https://imgur.com/gallery/fWEPPuN I also removed R1346 to isolate the blanking pin (not sure if needed)
Last edited by Zronium on Mon Aug 29, 2022 10:06 pm, edited 1 time in total.
Pencilman
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Re: TV RGB mod thread

Post by Pencilman »

tongshadow wrote:How old is this TV? Looks like a hot chassis to me.
I have no idea how old it is, but it's probably from the late 80s. It has AV input so I just assumed it was new enough.

How can you tell if it's a hot chassis?
KPackratt2k
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Re: TV RGB mod thread

Post by KPackratt2k »

Pencilman wrote:I have no idea how old it is, but it's probably from the late 80s. It has AV input so I just assumed it was new enough.

How can you tell if it's a hot chassis?
The easiest way to detect a hot chassis is if it has a transformer between the tuner and the Coaxial (RF) input. On a set that has AV inputs, you can tell if it's a hot chassis by optocouplers before the AV inputs to isolate them.

Since this is a late-80s TV, I'm guessing this would likely be too old to have a jungle chip with an RGB input (I haven't looked at the schematic to make sure), though you've stated that there is an unused RGB input that is tied to ground, but there's a chance that it's either disabled by the firmware or a digital TTL input (which will only give you 8 colors if you're lucky). The easiest way to test is to apply a voltage to the blanking pin while the TV is displaying static. If you get a black screen, it should be analog RGB and therefore modifiable.

If this is indeed a hot chassis, you will need an isolation transformer to prevent your input device from shorting out the TV.
Pencilman
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Re: TV RGB mod thread

Post by Pencilman »

KPackratt2k wrote:
Pencilman wrote:I have no idea how old it is, but it's probably from the late 80s. It has AV input so I just assumed it was new enough.

How can you tell if it's a hot chassis?
The easiest way to detect a hot chassis is if it has a transformer between the tuner and the Coaxial (RF) input. On a set that has AV inputs, you can tell if it's a hot chassis by optocouplers before the AV inputs to isolate them.

Since this is a late-80s TV, I'm guessing this would likely be too old to have a jungle chip with an RGB input (I haven't looked at the schematic to make sure), though you've stated that there is an unused RGB input that is tied to ground, but there's a chance that it's either disabled by the firmware or a digital TTL input (which will only give you 8 colors if you're lucky). The easiest way to test is to apply a voltage to the blanking pin while the TV is displaying static. If you get a black screen, it should be analog RGB and therefore modifiable.

If this is indeed a hot chassis, you will need an isolation transformer to prevent your input device from shorting out the TV.
I've read somewhere that if it's not a hot chassis the hot part of the board is marked. Well this board is divided in to 2 sections. The TV is assembled at the moment but I will check for the couplers tonight. Also, in the meantime I found another Daewoo TV that uses this same chip for the SCART. Not saying it's not disabled in this model but by following the pinout on the SCART I was able to identify the blanking pin so at least this is solved.

EDIT: Yup... It's a hot chassis. The AV inputs do indeed have optocouplers. Damn... I was hoping this wouldn't be such a hassle. Well... Back to the drawing board. I guess I'll be looking for a newer TV.

Image
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