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 Post subject: Re: TV RGB mod thread
PostPosted: Wed Feb 20, 2019 1:51 pm 



Joined: 14 Nov 2018
Posts: 87
Get so tired yest that i going start the mod just now, man that R111 is so tiny, what about if i just remove him and replace for one of same value and twist with the 680R?
EDIT: no i think i just mistake myself, going solder a wire downside the board maybe
here some pics of the board: https://imgur.com/a/sze3VI1
Thanks again!


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 Post subject: Re: TV RGB mod thread
PostPosted: Wed Feb 20, 2019 7:29 pm 


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Joined: 16 Feb 2009
Posts: 119
Location: Columbus, OH
Pikkon wrote:
LuckyDay wrote:
Otherwise though the rgb mod on the 14" looks great, and I have another set sitting and waiting to mod soon as well.


Does yours have a horizontal shift when using composite as sync,just tried rf as sync and and pretty much fixed it but don't really want to go to the trouble using that setup.


Quoting you because it sounds like you have a similar BA-4D modded to mine, but this question is really for anyone who happens to know.

My 14" 14M42 looks great as far as clarity, brightness, and sharpness, but I'm having difficulty adjusting white balance when the switch on my mod is set to RGB. With the switch turned off and using composite, the white looks great. When RGB is turned on, my whites are yellowish/reddish (using something like the Sega logo screen as an example it's very noticeable. This means other colors in the game are thrown off a bit too.

Has anyone experienced this difference after modding? I adjusted R.Cut, B.Cut, G.Cut, and the R.Drv, B.Drv.G.Drv as the service manual mentions for white balance, and was able to get it a bit closer, but it's still noticeably red/yellow in the white areas.

What I'm curious about is if this has anything to do with the components I'm using or anything as far as the wiring of my mod itself. Is it just trickier to adjust white balance using RGB rather than composite which is only Y/C?


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 Post subject: Re: TV RGB mod thread
PostPosted: Thu Feb 21, 2019 9:59 am 


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Joined: 26 May 2015
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Location: Florida
My 13inch is a BA-1 chassis and I don't have that problem.

You could try and experiment with some 1k pots on the rgb lines.


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 Post subject: Re: TV RGB mod thread
PostPosted: Thu Feb 21, 2019 2:59 pm 


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Location: Florida
I pickup up another sharp tv,this is a 27a-s120 from 91.

I can't find a service manual for it but did find the jungle ic and it's got me confused,think it's digital.
http://www.weisd.com/store2/NTE7054.pdf

Seems the B input(pin 17)and blanking share the same pin.


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 Post subject: Re: TV RGB mod thread
PostPosted: Thu Feb 21, 2019 7:15 pm 


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Location: Columbus, OH
Pikkon wrote:
My 13inch is a BA-1 chassis and I don't have that problem.

You could try and experiment with some 1k pots on the rgb lines.


Good idea, I have extra pots lying around I could use. Think this would work fine just wiring this right by the SCART socket using the ext RGB lines that are coming from that socket?


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 Post subject: Re: TV RGB mod thread
PostPosted: Sun Feb 24, 2019 4:02 am 



Joined: 24 Feb 2019
Posts: 2
Pikkon wrote:
I recently modded a sony kv-13tr29 for rgb and it came out great but when I got to adjusting the tv in the service menu HSIZ is locked in at 18 and is disabled,in the service manual it says Not Use for HSIZ,I can move the numbers up and down but has no effect and I tried using other ID-0 through ID-4 but that did nothing,other sets using the same BA-1 chassis have the HSIZ working so I guess it's locked out in software,kind of a bummer as I just wanting to move it just a bit.


There's another way to adjust the width, which will work on just about any TV you come across. All you have to do is locate the horizontal width cap, and change it out for a capacitor of a different farad value.

The horizontal width cap will almost always be a 0.10uf - 0.56uf poly cap with the voltage anywhere from 200v to 300v (though in some cases, as high as 630v). It will always be somewhere in the path of the horizontal yoke windings.

Using that information, you can almost always narrow it down to a single capacitor on the board. Usually lowering the value of it will increase width, but in some cases it may decrease it (depends on the circuit). To be safe, replace it with a capacitor of the same type.

LuckyDay wrote:
I have two 13" Sony's and both have the same limitations of the service menu. Which is a shame because they both have the same slight corner bowing, and some of the menu items that are not working are the PINAMP and C.PIN adjustments.


On these smaller sets you can adjust pincushion manually, using those small round magnets that you always see at the craft store, and some double-sided foam tape.


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 Post subject: Re: TV RGB mod thread
PostPosted: Mon Feb 25, 2019 3:57 am 



Joined: 13 Feb 2019
Posts: 4
Ok so im currently working on a Sony KV-32S40 it has a problem where it will work for a few minutes and then the image will go out but the sound still works. At first i thought it might be the flyback transformer so i replaced it it was good for about a day but then started doing it again. I thought maybe the tramsformer needed to be adjusted but theres no change. Not sure what i should check bext. I heard something about it being the HV Drive and to replace the jungle. Not sure if thats accurate or not. If so i have 2 extra cxa2095s chips. Any help would be appreciated. Really dont wantnto trash this one cuz i really like the image on ot.


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 Post subject: Re: TV RGB mod thread
PostPosted: Tue Feb 26, 2019 7:11 pm 



Joined: 14 Nov 2018
Posts: 87
Wigz81 wrote:
Ok so im currently working on a Sony KV-32S40 it has a problem where it will work for a few minutes and then the image will go out but the sound still works. At first i thought it might be the flyback transformer so i replaced it it was good for about a day but then started doing it again. I thought maybe the tramsformer needed to be adjusted but theres no change. Not sure what i should check bext. I heard something about it being the HV Drive and to replace the jungle. Not sure if thats accurate or not. If so i have 2 extra cxa2095s chips. Any help would be appreciated. Really dont wantnto trash this one cuz i really like the image on ot.

dude try to redone every bad solder spot that you find, besides that theres not much to do unless use the tube on another set because nobody gonna know if theres a faulty component


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 Post subject: Re: TV RGB mod thread
PostPosted: Tue Feb 26, 2019 7:13 pm 



Joined: 14 Nov 2018
Posts: 87
So guys i finish my sharp mod, theres what it turns out lol
https://imgur.com/a/JWfXwxB

I think the lesson here is: if the set is too old, just let the thing alone with composite, now i never gonna know whats going wrong, the horizontal lines show clearly some bad solder spot or faulty component, you know its all right its all part of the experiment, you cant open a 20 years old TV and expect he gonna just turn on like new after. Anyway i thank you guys for all Pikkon Mark Syntax and all the others, was a nice learning and i gonna keep learning, until next guys! bye bye!


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 Post subject: Re: TV RGB mod thread
PostPosted: Tue Feb 26, 2019 8:18 pm 


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Joined: 26 May 2015
Posts: 69
Location: Florida
Did you try and adjust the screen voltage on the flyback,might be worth a try.


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 Post subject: Re: TV RGB mod thread
PostPosted: Tue Feb 26, 2019 9:46 pm 



Joined: 14 Nov 2018
Posts: 87
Pikkon wrote:
Did you try and adjust the screen voltage on the flyback,might be worth a try.

Man not even think about this, i not even touch the things with power on because im not a technician, well who knows with cauntion maybe i can do this.
here some pics of the drilling part (the fun part) i gonna edit this album later: https://imgur.com/a/ejTCgJo
EDIT: Pikkon are you talking about the screen pot? because i think i let the thing gets misfit when i was working on the board.


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 Post subject: Re: TV RGB mod thread
PostPosted: Wed Feb 27, 2019 6:38 pm 



Joined: 24 Feb 2019
Posts: 2
Wigz81 wrote:
Ok so im currently working on a Sony KV-32S40 it has a problem where it will work for a few minutes and then the image will go out but the sound still works. At first i thought it might be the flyback transformer so i replaced it it was good for about a day but then started doing it again. I thought maybe the tramsformer needed to be adjusted but theres no change. Not sure what i should check bext. I heard something about it being the HV Drive and to replace the jungle. Not sure if thats accurate or not. If so i have 2 extra cxa2095s chips. Any help would be appreciated. Really dont wantnto trash this one cuz i really like the image on ot.


Do you lose high voltage when the picture goes out? If you still have high voltage and/or neck glow, then you can rule out the Jungle/H Drive/HOT/Flyback as being the problem, at least when it comes to catastrophic failure.

These problems are usually caused by bad solder connections.

The low hanging fruit, is to carefully and lightly tap around the chassis with the back end of an insulated screwdriver. If the problem changes as you tap, then it's for sure a bad solder connection. Tapping around lightly can help you determine roughly where the problem is. If you're not comfortable doing this while powered on, then just resolder everything that looks suspect.

If you have a decent multi-meter (or O-scope) there's some other things you can check to help narrow down the issue. For instance, you should be able to follow the video signal from video input jack, to the input of the Jungle, then out of the Jungle and to the neck board. R/G/B voltage in the output stage (on the neck-board) should be somewhere in the 100-200v range. Nowhere near enough to kill you, but it can give you a nice little zap if you're not careful.

When you say the image goes out, are you talking about the video signal (ie composite, component, etc)? The OSD? Both?


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 Post subject: Re: TV RGB mod thread
PostPosted: Thu Feb 28, 2019 12:19 am 


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Posts: 119
Location: Columbus, OH
Success with another Sony 14M52 today, but one issue. The service menu changes that I make will not save, even when powering the TV off (not unplugging it from the AC outlet).

This means color calibration is way off, and there seems to be no way to fix it. Anyone encountered this on a Sony, and is there a fix or can a RAM chip be replaced, or is there some sort of battery in the board that is used to store settings? I don't see a battery of any type in the manual.

When in the menu using the mute+enter method shows the 'Write' message, and it appears to work as I'm doing it, but they still don't save.


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 Post subject: Re: TV RGB mod thread
PostPosted: Thu Feb 28, 2019 2:32 pm 


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Location: Florida
Your tv might have a eeprom.

Guess the setting from the factory are in place.


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 Post subject: Re: TV RGB mod thread
PostPosted: Thu Feb 28, 2019 2:43 pm 


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Pikkon wrote:
Your tv might have a eeprom.

Guess the setting from the factory are in place.


Yeah, it does and it's possible that chip is bad. I'm going to look into replacing it since it's only $1.


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 Post subject: Re: TV RGB mod thread
PostPosted: Mon Mar 04, 2019 4:58 pm 



Joined: 13 Oct 2015
Posts: 46
Did you hit Enter after Mute+Vol+ to save the write?


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 Post subject: Re: TV RGB mod thread
PostPosted: Mon Mar 04, 2019 6:41 pm 



Joined: 24 Jun 2017
Posts: 3
Hi, long time lurker here, and I finally picked up a TV that was a good candidate for a RGB mod. It's a Sony Trinitron KV-27V40, it uses a BA-4 chassis, so anyone else with the same chassis should be fine with copying my setup. Big shout out to MarkOZLAD for his resistor calculator spreadsheet, saved me a lot of trouble selecting proper resistor values. On to the pics!

If your going to do this to your TV, I'm going to assume you know how to discharge the anode cap, and disassemble the TV without breaking something or blowing yourself up. Without further ado, here's the relevant part of the service manual.
Image
Here we can see our RGB lines coming out of the Microcontroller, and going through a voltage divider before heading off to the jungle IC. 5.6Kohms inline, 680 Ohms to ground. Nothing too special here. Blanking is where things get weird. It seems there are 2 outputs from the Micom heading to the blanking pin of the jungle IC. I simply made my blanking circuit very similar to the top one, just a diode and a 1Kohm resistor. Here's pics of the components on the board.
Image
R025, R026,and R027 are red, green, and blue respectively, and D003 is where I'll put my blanking signal. Also, you can see the header for an optional PiP board, which is where I'll get my ground.
Here's a pic of the underside of the board underneath those resistors.
Image
R086, R087, and R088 are the factory OSD pulldown resistors, but they're the wrong size for what we're doing, so they have to go. I removed them by adding enough solder to cover both sides of the resistor, which caused them to stick to the soldering iron, then it's a simple matter of flicking them off the iron. The results look like this.
Image
As for the rest of the mod, I figured out that when you clear the vias on this board with a solder sucker, there is enough room to poke another component's leg into that via. Here are the results.
Image
In the 3 shrinkwrap tubes are a 910 ohm and a 75 ohm resistor soldered together, the union is where my external RGB comes in, the 910 ohm leg going down into the existing resitor vias, and the 75 ohm leg going go the unused ground behind (hidden under the shrinkwrap tubes). Blanking is going through a 1kohm resistor, a diode, and then into the via by D003. I decided to make this function similar to a Scart TV, so blanking will be enabled by the external device sending 5V to the TV, but I also wanted to add a toggle switch so I could manually force blanking on if the device I connect doesn't have 5V available on it's AV port. I needed to find a source of switched 5V on the board, which was actually kinda hard to find, seeing as how Micom is on 5VSB, Turns out the tuner needs switched 5V, so I grabbed it off a nearby capacitor C626. Like so.
Image
Here's the completed mod, minus the plate I made for the back of the TV.
Image
Now for the moment of truth! Here's my test subject, Mega Bomberman on a Sega Genesis 2, VA3 motherboard (3/4 board).
Image
here's the same, via RGB instead.
Image
Final thoughts and notes: MASSIVE improvement over composite, from both my Genesis and Raspberry PI (RGB via GERT666 board). As for sync You CAN put it in through the composite port, but I suggest using the S-Video port, since it bypasses the comb filter IC, which fixes the issue with the image shifting offscreen to the left. So far I've tried CSYNC and composite video sync over S-video, and they both work fine. The presence of the unused PiP board port leads me to believe that it's also possible to add component inputs as well, I might need to revisit this unless I can find a simple and cheap solution to convert YUV to RGB (some consoles I want to use have component out, but not RGB. Overall, a relatively simple mod with fantastic results! I still need to fix some minor purity and convergence issues with this TV, but other than that, it's perfect! Thanks to all who have contributed to this forum, It's simply the best repository on the internet for RGB modding!


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 Post subject: Re: TV RGB mod thread
PostPosted: Mon Mar 04, 2019 6:47 pm 


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Posts: 119
Location: Columbus, OH
darknezz19 wrote:
Did you hit Enter after Mute+Vol+ to save the write?


Fixed this problem from earlier. I replaced the EEPROM with another I had on a spare board, and the writes work now.

If I had to guess, I'd say I probably burned up this board by mistake when soldering to the 5V pin for my blanking circuit on the RGB mod. I moved the 5V source to another IC, and replaced the EEPROM and things are working now.


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 Post subject: Re: TV RGB mod thread
PostPosted: Fri Mar 15, 2019 5:21 am 



Joined: 11 Sep 2015
Posts: 12
Just picked up a Toshiba 14AF44 and would love to RGB mod this set. Anyone have any diagrams/photos/install docs for this particular model?

Also, I'd appreciate any tips for discharging the tube. I'm particularly terrified of dying and would appreciate any tips. Any gear, gloves, steps you would recommend? Any and all help is appreciated.


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 Post subject: Re: TV RGB mod thread
PostPosted: Fri Mar 15, 2019 11:33 pm 



Joined: 18 May 2017
Posts: 510
Had a quick look and it seems that this TV has digital RGB coming from the micom to the jungle. I’ve been wrong before but it seems unlikely to be moddable.
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OSD/External RGB Mux Diagram
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 Post subject: Re: TV RGB mod thread
PostPosted: Sat Mar 16, 2019 11:42 pm 


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Hi there,

Been lurking around here for a long time, but had a troubleshooting question I can't seem to answer-

I recently modded a Sharp 27N-S300 to use with a cab project, and it has worked more-or-less fine, with the exception that there is about a 2 inch wide vertical band of faintly lighter/discolored screen on the far right edge. I'm 99.9% sure it's EMI on the ground wire. I've already relocated the jacks and switch and the wiring in general, and finally seem to have narrowed it down to when I physically move around just the ground wire. I've also tried changing the ground points between several candidates. I can actually manipulate it into a position where there is no imbalance with the chassis slightly cracked open, but the forward positioning that happens when I actually close the case brings it back.

I'm using generic insulated 22AWG copper wire. Any tips from anyone else who has dealt with this? Any workable shortcuts such as a sheath or shielding tape I can throw on it?

Thanks-

EDIT: Disregard; took so long to get approved that I got it sorted! Turned out it wasn't so much EMI as having to crank up the cutoff so much (input was pretty low). I added in series resistors per Ozlad's table and it resolved it; still have to crank up the cutoff, but only about half as much. That was enough to remove the jailbar.


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 Post subject: Re: TV RGB mod thread
PostPosted: Fri Mar 22, 2019 10:44 pm 


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Spoke too soon; problem jailbar is still there, but fainter and most visible in a darkened room (or a light colored background, like blue skies in Carrier Wing). I'm completely stumped now and looking for advice.

Specimen is a Sharp 27N-S300; service manual is here.

I initially was chicken (knowing my klutzy limitations) and trying to avoid pulling pins on the IC, so I chose to pull and inject the RGB lines from the 6.8k resistors right after the controller chip. All OSD lines were pulled from there and put through replacement 6.8k resistors on their way to the switch. RGB inputs were coming from 75ohm terminated BNC jacks and fed back into the opposite pads. To facilitate this, I pulled up the 2.2k termination resistors, R803 804 and 805, from in front of the jungle, so that the RGB was just going through the stock 0.1uf caps once it came back from the switch. Leaving these gone caused the OSD to turn into a bleeding mess, so I later added 2.2k terminations back to the OSD lines on their way to the switch.

5v was pulled straight off the mainboard 5v regulator, which is a hike away. Blanking line was originally wired back into the bottom of the pin on the jungle, since the OSD blank didn't have an equivalent series resistor to hijack.

This configuration was functional, but levels coming in were low. Raising the cutoffs by a pretty substantial number (about 80 above default) made the image look fine on 240p Test color bars. And, of course, I noticed the jail bar for the first time.

The bar ONLY appears on the external input, not the OSD; and it also appears regardless of whether there is a source plugged in. The bar is the far right edge of the screen, and the left edge of the bar has a (very slowly) rippling/wave effect to it. Even then, it wasn't extremely noticeable except on a dead/black screen, but was more visible on certain lighter or darker color backgrounds. It's one of those things that once seen, you can't UN-see, and probably wouldn't be very noticeable to some, but then I wouldn't be modding a CRT in the first place if I wasn't perfectionistic...

My initial install was particularly sloppy and had some extra-long runs of wire to facilitate the way I initially had the jacks installed in the back case (so that I could actually remove the case without yanking wires out). I noticed that moving around the ground wire did affect the bar, and moving the switch assembly far enough back from the board could actually make it disappear entirely. Worth noting that the switch is mounted just above the s-video jack, which is adjacent to the RF modulator. I started hypothesizing that it was EMI of some sort.

After my first post, I went back to the drawing board. First I tried moving the BNC jacks further away from the flyback to see if that helped, but no effect. I then tried moving the ground wire around between various grounds in the chassis, including on the unused PIP board, but it had no effect (other than the usual weirdness from moving it around). Then I tore everything apart and did a more conventional install; pulled the pins like normal (and broke off one of them, as feared, but managed to fix it). I also dremeled out the part of the case housing the jack covers so that I could just keep that plate on the mainboard where the switch and BNC jacks were located. I rewired the switch entirely so that all of the lines are as short as possible, and mostly tidy, with the exception that the 5v line is still quite long based on where it's coming from, and the OSD blanking line to the switch still has a little more slack than most. There are now replacement 0.1uf caps on the RGB outputs from the switch, and I tried putting 1.1k series resistors on the external RGB coming in to the switch.

Initially this seemed to eliminate it; the 1.1k resistors also seemed to help the levels, to where the cutoffs only need to be raised 40-50 points above stock. It can't be seen on a black screen in a lighted room, but it's still there with the lights out, or faintly on particular backgrounds if you look for it.

I have no idea where to go from here. I'm faintly wondering if I should further increase the resistance on the inputs to see if it raises the levels more, but the bar is there even when I reduced the cutoff levels back to stock. I never replaced R802 for the OSD blanking line (a 3.3k termination before the jungle), but I've had no problem with the OSD, and I have read only that you're supposed to tie the 5v blanking signal high. Can interference like that come on the 5v line due to its length, or something to do with the quality coming out of the regulator? Should I tie it to something different and closer? Any completely different ideas?

Thanks!


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 Post subject: Re: TV RGB mod thread
PostPosted: Sun Mar 24, 2019 7:32 am 



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Posts: 341
DJO_Maverick wrote:
Specimen is a Sharp 27N-S300; service manual is here.


I apologize for this not being helpful, but a 27N-S300 popped up for free near my father's house via craigslist, and I'm thinking of asking him to pick it up. If you have any comments on the quality of the picture, I'd be interested to read them. Good luck with your modding!


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 Post subject: Re: TV RGB mod thread
PostPosted: Sun Mar 24, 2019 1:53 pm 


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SamIAm wrote:
I apologize for this not being helpful, but a 27N-S300 popped up for free near my father's house via craigslist, and I'm thinking of asking him to pick it up. If you have any comments on the quality of the picture, I'd be interested to read them. Good luck with your modding!


Notwithstanding that band, it's a sharp, pretty picture. It also syncs reasonably well to some sub-60hz signals (using it with an RGB-Pi). It even had a pretty solid picture just on S-Video. Geometry is surprisingly great, as was convergence.

I have PVM20M2MDU that I use for my consoles (this was intended to be for an arcade cab), but this made me a believer in TV modding; I've got a 32" Sony next in line now that I'm intending to supersede my PVM for everyday use, but I'm waiting until I have this one completely figured out before I tear that one open.


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 Post subject: Re: TV RGB mod thread
PostPosted: Tue Mar 26, 2019 12:32 am 



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DJO_Maverick wrote:
Notwithstanding that band, it's a sharp, pretty picture. It also syncs reasonably well to some sub-60hz signals (using it with an RGB-Pi). It even had a pretty solid picture just on S-Video. Geometry is surprisingly great, as was convergence.

I have PVM20M2MDU that I use for my consoles (this was intended to be for an arcade cab), but this made me a believer in TV modding; I've got a 32" Sony next in line now that I'm intending to supersede my PVM for everyday use, but I'm waiting until I have this one completely figured out before I tear that one open.


Looks like I'll be bugging my old man! Thank you!


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 Post subject: Re: TV RGB mod thread
PostPosted: Thu Mar 28, 2019 4:54 am 


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Still hoping to get an opinion from a veteran about my mod...

I tried playing around with the theory that maybe it was something to do with voltage being too high on the blanking line and gave it a 6.8k resistor to match the stock one on the OSD, but no effect. Now I'm wondering if perhaps my jungle is one that wants 0.5 instead of 0.7 (I've scoured the service manual and can't find that; it's another IX3253CE that's equiv to TA1268N, but I can't seem to find that detail in its datasheet either). I'm just guessing that the 1.1k resistors I threw on the input lines after the ground terminations carried me closer to 0.5 and that's why it seems to have improved, but I'm useless at accurately calculating voltage/resistance.

The problem doesn't photograph well, especially now that it doesn't show up on pure black anymore with the additional resistors; it's mainly noticeable in motion and on colors that are dimmer, but not black; if the screen region is moderate to full brightness, the discolored area isn't visible.

Has anyone who fed 0.7 to a jungle that wants 0.5 ever experienced anything similar...? Or any issues with working on a Sharp? I'd be happy just to accurately diagnose the cause at this point.


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 Post subject: Re: TV RGB mod thread
PostPosted: Thu Mar 28, 2019 11:20 am 



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Posts: 510
Don’t know about the TA1276N but the TB1238N says 0.5V in the datasheet. I have put 0.7Vp-p into it no problem, in fact I’ve put more than that and it’s only resulted in an over-bright picture.

If you did want to attenuate the RGB you need to put resistance on the console side of the termination resistor. Not on the TV side. Basically before it enters the set. Try a 500 ohm pot on each line if you want. Tim says to use 24R/51R to make 0.5Vp-p, see his earlier post. I’ve not tried that yet, could be worth a try.

For wiring I like to use shielded VGA cable with shields grounded onto TV chassis and at the connector. Maybe just try adding shielded cable to the sync line and ground the shield.

I’m no expert at jail bars but I’ve mostly heard of them starting on the left and fading out to the right.


EDIT: The chip I meant was a TB1238N sorry. From experience this family of chip state 0.5Vp-p in datasheet.
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OSD/External RGB Mux Diagram
OSD/External RGB Mux Resistor Value Table 0.7Vp-p : 0.5Vp-p


Last edited by MarkOZLAD on Fri Mar 29, 2019 4:35 am, edited 1 time in total.

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 Post subject: Re: TV RGB mod thread
PostPosted: Thu Mar 28, 2019 10:20 pm 



Joined: 28 Mar 2019
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Hey y'all, I thought I'd give this whole RGB mod thing a shot on a little Sylvania CRT I got... SRT2319A is the model number for anyone interested.

Anyways, I opened it up and found that it doesn't actually have a jungle chip, everything comes from one tiny microcontroller (M61271M8-058FP)

Looking around I eventually found this service manual from a different TV manufacturer but the board seems to be identical:
http://www.dragons-lair-project.com/tec ... st419e.pdf

Looking at the IC functions here I noticed that pins 19, 20, and 21 are unused and not connected to any traces, also listed as unused are 29 and 30 which someone else online claimed were chroma/luma inputs, so I have hope 19-21 could be RGB inputs. I don't know how exactly to safely test if they are though

I'm pretty new to this stuff and would have to practice with my iron a while before I start soldering directly onto pins that small, but I'm wondering what exactly I would need to hook up to this thing? If it's all on one IC... do I need resistors and such is what I mean... Pretty complicated stuff


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 Post subject: Re: TV RGB mod thread
PostPosted: Fri Mar 29, 2019 4:02 am 


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Joined: 16 Mar 2019
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Thanks so much for the response; it helped, and I'm cautiously optimistic I'm on the right track. I found a calculator and am thinking my odd in-between setup was putting out .68vpp, which gave the slight benefit... and I had some 33 ohm resistors available, so I redid it for the moment as 33/75, which I believe should be .51vpp but with improper impedance. That seemed to give another (less dramatic) contrast boost over .68, and dissipated my weird interference even more. I ordered 24/51s and will give that a shot this weekend to see how far it takes me.

I'm drawing a tentative conclusion that the IX3253CE (and clones) want 0.5 and actually LOSE brightness at 0.7 instead of being over-bright. At this point, color levels and picture look awesome other than this weird ripple-bar-thing. I'm not sure the overvoltage is the sole cause of that at this point, but it appears to at least be a contributing factor.

I don't really think it is a jailbar, because I'm familiar with what those look like, and this doesn't seem like that... but I've had a hard time finding anybody else describing something quite like this, and that's the closest term I can think of. It's a slightly amorphous bar on the right ~2 inches that is a little wider at the top and maybe 3/4 of the way down, so sort of an s-shaped left edge... and everything in it is consistently just a smidge darker than the left of the line. At this point, it's only visible on a fairly narrow range of darker colors, so a lot of games you never even see it if you try. It almost looks like something that would come from playing with a magnet around a set, but it's clearly being mitigated some by playing with the resistors and reducing vpp going into the RGB lines. It's never flickering or any other obvious interference pattern... just kinda there.

I'm wondering if it's still due to a bad ground, or maybe signal reflection happening due to the IC wanting .5 and the input still being terminated with 75ohm? I've tried every reasonable grounding option available other than the IC itself; may try shifting the ground there if the 24/51 doesn't resolve it fully.


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 Post subject: Re: TV RGB mod thread
PostPosted: Fri Mar 29, 2019 5:12 am 



Joined: 18 May 2017
Posts: 510
I have done up a table to calculate the inline resistors when doing OSD External RGB Mux method with jungles that require 0.5Vp-p.

Image

This assumes you use the pattern of 24R/51R Tim suggested on an earlier post.

Image Note the inline resistor we are calculating not shown here..
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MarkOZLAD
OSD/External RGB Mux Diagram
OSD/External RGB Mux Resistor Value Table 0.7Vp-p : 0.5Vp-p


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