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 Post subject: Re: TV RGB mod thread
PostPosted: Tue May 18, 2021 1:58 pm 



Joined: 10 Dec 2020
Posts: 5
re: https://shmups.system11.org/viewtopic.php?p=1443752#p1443752

vol.2 wrote:
The geometry issues sound like it might be vertical linearity. If you can't access that in the service menu, it would be worth looking around on the motherboard. In fact, if you can find any physical geometry controls at all, it's probably best to set the service menu at mid-way and adjust the physical pots until it generally looks good.

IAC, to adjust linearity, you'll need the grid pattern, and you can measure the height of the boxes in the grid, adjusting to make them all as equal as possible from top to bottom.

Unfortunately there's no physical controls inside this TV whatsoever, aside from the G2 and Focus pots on the flyback itself. The service menu does have some controls for vertical linearity, but I'm actually having trouble with horizontal linearity, as best I can tell. For reference, here's the 240p Test Suite grid pattern, and here's the scroll test. (Apologies for the flashing in the video; I could not get a clean recording to save my life.)

vol.2 wrote:
You can narrow down caps that you might want to replace by sections on the board. The flat screen CRTs are more difficult, and I don't think caps are always the problem there. Sometimes the LOPT gets weak, or some other part of the system starts to wear. However, you can probably improve the geometry at least a little by checking and replacing any out of value (20% or more) caps in the Horizontal and Vertical sections, and anything electrolytic that's directly coupled to the LOPT (if there is any).

You don't need to mess with anything in the control electronics or the tuner section as that stuff is probably fine and doesn't see much heat or wear. the most suspect things are small caps that are near hot component, as those tend to dry out. That's mostly around the HV, and the power section near any big transistors/heat sinks or any banks of power resistors, and especially anything near a spot on the PCB that looks burn in any way.

I did end up replacing a fair few capacitors, and that did help with some stray geometry issues that the display had, but didn't do much if anything for this linearity issue. I'm afraid at this point I might just have to deal with it as the price of using a flat CRT.

I'm also seeing the same problem that it seems is fairly common with RGB displays in general, where the image is offset to the left in RGB mode. (See the above screenshot, as well as the PlayStation boot screen for reference.) While the service menu does have an option for horizontal shift, that option only seems to work for composite input. It doesn't have any effect whatsoever on RGB. Interestingly, some games I've tried on this TV have a screen-shift option that allows the picture to get into that unused area on the right, but I've had no such luck with the controls on the TV itself.


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 Post subject: Re: TV RGB mod thread
PostPosted: Tue May 18, 2021 2:55 pm 


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FantasticMrSocks wrote:
For reference, here's the 240p Test Suite grid pattern


Doesn't look too bad to me. There's some flagging or something, but linearity looks pretty decent. The flagging may be caused by the input signal and not the set.



Quote:
I did end up replacing a fair few capacitors, and that did help with some stray geometry issues that the display had, but didn't do much if anything for this linearity issue. I'm afraid at this point I might just have to deal with it as the price of using a flat CRT.


There might be something in the power rails that's out of spec still if you didn't look at those. You might go back and make sure the filter caps on the video transistors are okay, and anything supplying power to video.



Quote:
I'm also seeing the same problem that it seems is fairly common with RGB displays in general, where the image is offset to the left in RGB mode.


I'm not really familiar with that set, but the Sony flat screen I have has separate geometry and centering controls for different inputs. If that one does not, then I don't know what to tell you. I'd be somewhat surprised if there weren't physical controls for any centering whatsoever in a TV that big, but I don't know anything about AKAIs. I have a couple smaller TVs from the 80s that have no centering controls, but I would have guessed that there would be something in a set that new.
I would look again at the signal flow in the input stages and see if there isn't any pots on secondary boards or anything. Sometimes it's not a switch, but a variable capacitor or inductor or something. There would be a big coil with a slug in the middle that can be adjusted. If you find it, be careful to mark the starting position.


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 Post subject: Re: TV RGB mod thread
PostPosted: Tue May 18, 2021 3:34 pm 



Joined: 10 Dec 2020
Posts: 5
vol.2 wrote:
Doesn't look too bad to me. There's some flagging or something, but linearity looks pretty decent. The flagging may be caused by the input signal and not the set.

Maybe "linearity" isn't actually the right word for it, but here's what I'm trying to describe. It's more noticeable in motion, but there's definitely an inconsistency in how wide things appear in different areas across the screen. It makes horizontal scrolling real troublesome.
"Flagging" refers to the 'curled-in' corners, right? There are a few different settings in the service menu that can adjust those; it might just be a matter of fiddling with it until it looks acceptable. Or, like you said, it might come from the input as well.

vol.2 wrote:
There might be something in the power rails that's out of spec still if you didn't look at those. You might go back and make sure the filter caps on the video transistors are okay, and anything supplying power to video.

When I get back inside it I'll definitely have to have a look at that.

vol.2 wrote:
I would look again at the signal flow in the input stages and see if there isn't any pots on secondary boards or anything. Sometimes it's not a switch, but a variable capacitor or inductor or something. There would be a big coil with a slug in the middle that can be adjusted. If you find it, be careful to mark the starting position.

I'll definitely keep that in mind. Now that I think about it, I know that there are a few pots on the neck board, but I'm not sure what they do, and when it comes to the neck board I definitely don't want to just start tweaking things without knowing what they are. I'll have a look around the input areas, though, and see if I can find anything useful.

Also, thanks for replying to my posts! I know I'm just one of many people looking for help, and it's awesome that all the knowledgeable folks in this thread are willing to help everyone out. If I see a question that I happen to know the answer to, I'll be sure to do the same.


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 Post subject: Re: TV RGB mod thread
PostPosted: Tue May 18, 2021 5:40 pm 


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FantasticMrSocks wrote:
Maybe "linearity" isn't actually the right word for it


No, you were right. It's hard to tell in a photo/video, but that's linearity alright. There may be some coil or something to adjust it if it's not in the service menu.

Quote:
"Flagging" refers to the 'curled-in' corners, right?

Yes, it's more typically on the top of the raster. IIRC, it typically is caused by sync issues, and more specifically the serration of vertical pulses.

Quote:
I know that there are a few pots on the neck board, but I'm not sure what they do


There are typically 5 pots on the neck board. RGB cutoff and GB bias. Those are what you use to set the color balance and have nothing to do with geometry. I've never seen geometry controls on a neck board newer than 1980, it's highly unlikely that they will be in that area. You need to look at the schematic and find the path of the horizontal and vertical geometry. There would be coils and variable resistors in the schematic for you to find on the board. (assuming they exist)


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 Post subject: Re: TV RGB mod thread
PostPosted: Tue May 18, 2021 8:54 pm 



Joined: 30 Apr 2018
Posts: 79
I think I broke the component input on my 24FV300 while taking the case off and I can see the crack right where the input is so I was wondering if an RGB mod was possible to allow me to use the fantastic tube with a high quality input still. Here is the service manual https://www.manualslib.com/products/Son ... 57957.html I'm a total noob at RGB modding so I have no idea what to look for.

Here is what the crack on the board looks like it only looks bent on the top but there must be some kind of issue inside. https://imgur.com/a/g3viF9k


Last edited by Roboplodicus on Tue May 18, 2021 9:44 pm, edited 1 time in total.

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 Post subject: Re: TV RGB mod thread
PostPosted: Tue May 18, 2021 9:33 pm 


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Roboplodicus wrote:
I think I broke the component input on my 24FV300 while taking the case off and I can see the crack right where the input is


There shouldn't be a huge issue repairing the component inputs. That's going to be way easier.

I'll let someone else comment on the feasibility of rgb mod, but I know that many people have asked here about it and all (most?) told that it's a no-go for one reason or another.


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 Post subject: Re: TV RGB mod thread
PostPosted: Tue May 18, 2021 9:36 pm 


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Roboplodicus wrote:
I think I broke the component input on my 24FV300 while taking the case off and I can see the crack right where the input is so I was wondering if an RGB mod was possible to allow me to use the fantastic tube with a high quality input still. Here is the service manual https://www.manualslib.com/products/Son ... 57957.html I'm a total noob at RGB modding so I have no idea what to look for.


Single chip (Micro/Jungle) design so no RGB mix. You can probably get your component inputs working though.


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 Post subject: Re: TV RGB mod thread
PostPosted: Tue May 18, 2021 9:46 pm 



Joined: 30 Apr 2018
Posts: 79
Here is what the board looks like I on the surface it looks like the board is just bent but the damage must be worse inside and I'm not sure how to read a circuit diagram to repair the issue
https://imgur.com/a/g3viF9k

https://www.manualslib.com/manual/98841 ... KV-24FV300
thats the service manual


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 Post subject: Re: TV RGB mod thread
PostPosted: Tue May 18, 2021 9:53 pm 


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Roboplodicus wrote:
Here is what the board looks like I on the surface it looks like the board is just bent but the damage must be worse inside and I'm not sure how to read a circuit diagram to repair the issue
https://imgur.com/a/g3viF9k


What you're going to have to do is:

1) Reflow the connector solder joints

2) Put thick bodge wires across the traces that span that crack. Go over the board with you eyes very carefully and just give each one of those traces that has been cracked a second path (wire). You can do this by finding components (or test points) that are on the other side of the crack, and just using those to create the connection.

All-in-all, that's NBD, assuming it's just a cracked PCB. You don't need to read the schematic to fix this one. What you DO need is a multimeter. You must check continuity across all the traces that span the crack and make sure you get Zero Ohms across all those traces, and make sure it doesn't break if you stress the board. If it does break, you put a wire across the crack. That's all you should have to do, assuming this is the one and only cause.


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 Post subject: Re: TV RGB mod thread
PostPosted: Tue May 18, 2021 11:07 pm 


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If you cant fix a cracked board then go play with something else safer.
Maybe try take some pictures that actually show the damage instead of a zoomed in close up of nothing.

The first TV I ever fixed was a chassis snapped in half when I was 14 with mums lead light iron.

The repair you are attempting is childs play and shouldn't need a guide.


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 Post subject: Re: TV RGB mod thread
PostPosted: Wed May 19, 2021 3:31 am 


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FantasticMrSocks wrote:
Unfortunately there's no physical controls inside this TV whatsoever, aside from the G2 and Focus pots on the flyback itself. The service menu does have some controls for vertical linearity, but I'm actually having trouble with horizontal linearity, as best I can tell. For reference, here's the 240p Test Suite grid pattern, and here's the scroll test. (Apologies for the flashing in the video; I could not get a clean recording to save my life.)


You won't find any adjustments for horizontal linearity on a consumer TV. That is governed by a combination of film capacitors and a linearity coil, none of which are adjustable. Unfortunately, with flat consumer CRTs (and Akai is not a top quality brand) the manufacturers did the bare minimum in this regard and most of them have some issues. Even Sony and Panasonic couldn't get this right on their high end flat TVs - my $1500 MSRP Wega isn't much better although otherwise it's awesome.

Sadly, bad linearity is usually the price you pay for having a flat CRT. Some of them are quite good but it's pretty hit or miss. I don't think you could improve on it much.

Quote:
I'm also seeing the same problem that it seems is fairly common with RGB displays in general, where the image is offset to the left in RGB mode. (See the above screenshot, as well as the PlayStation boot screen for reference.) While the service menu does have an option for horizontal shift, that option only seems to work for composite input. It doesn't have any effect whatsoever on RGB. Interestingly, some games I've tried on this TV have a screen-shift option that allows the picture to get into that unused area on the right, but I've had no such luck with the controls on the TV itself.


Is there an option to shift the position of the OSD? That could possibly work.

Or you could buy an Extron RGB unit, they're easy to get and have a horizontal shift function.


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 Post subject: Re: TV RGB mod thread
PostPosted: Wed May 19, 2021 3:49 am 


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Sometimes the linearity coil is adjustable


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 Post subject: Re: TV RGB mod thread
PostPosted: Wed May 19, 2021 4:53 am 



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Posts: 794
Roboplodicus wrote:
I'm not sure how to read a circuit diagram to repair the issue


It's like playing connect the dots.
_________________
___________________________________________________
MarkOZLAD
OSD/External RGB Mux Diagram
OSD/External RGB Mux Resistor Value Table 0.7Vp-p : 0.5Vp-p

"Imagine toggle switch OSD modding a TV in 2019" - maxtherabbit


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 Post subject: Re: TV RGB mod thread
PostPosted: Wed May 19, 2021 6:21 am 



Joined: 02 Jan 2021
Posts: 10
KPackratt2k wrote:
Now that I'm done modding the RCA E13309 13" TV, I've decided to move onto my Sony KV-20EXR20 20" TV. Even though this model lacks Picture-in-Picture, the PIP header (A-31) is still active as I was able to blank the screen by applying voltage to the YS pin, which should make it ready to go without having to use an I2C modchip. I've put together a quick diagram for modding and I'd like to know if there's anything else that I need to do with it before I proceed.

WIP Mod Diagram: https://imgur.com/a/dkCX1ZA
Service Manual: https://elektrotanya.com/sony_anu2_chassis_kv27exr20.pdf/download.html

On the model with PIP (KV-27EXR25), there are 100 ohm resistors between the jungle chip (CXA1313S) and the A-31 header. I've added three 100 ohm resistors on the RGB lines (R316-R318) and a 150 ohm resistor on the YS line (R319) as suggested by a previous post for better handling of the higher blanking voltage. Does this sound like the right thing to do or should I remove the resistors?


Nope, looks all good there, but how are you getting it to blank? I'm working on this same set and can't get it to blank for some reason. Did some sets come with the PIP header left active and some didn't? There's a jumper at the front of the unit for PIP, does that need to be jumpered?

EDIT - Nevermind, i'm stupid. Actually LOOKED at the circuit this time and saw those missing resistors between the header and the jungle. Of course it wouldn't blank if there's no path lol


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 Post subject: Re: TV RGB mod thread
PostPosted: Wed May 19, 2021 7:15 am 


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maxtherabbit wrote:
Sometimes the linearity coil is adjustable


Have you seen a consumer TV where this is the case?


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 Post subject: Re: TV RGB mod thread
PostPosted: Wed May 19, 2021 12:20 pm 


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matt wrote:
maxtherabbit wrote:
Sometimes the linearity coil is adjustable


Have you seen a consumer TV where this is the case?

come to think of it, no :P


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 Post subject: Re: TV RGB mod thread
PostPosted: Wed May 19, 2021 2:17 pm 



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maxtherabbit wrote:
matt wrote:
maxtherabbit wrote:
Sometimes the linearity coil is adjustable


Have you seen a consumer TV where this is the case?

come to think of it, no :P

I had a look at the service manual and inside the TV, and can confirm that the linearity coil is not adjustable. After some reading, though, it looks like my problem is with S-correction rather than linearity. Best I can tell, S-correction is handled by one or more of the film caps in the horizontal deflection circuit.
Spoiler: show
Image

I'm learning this as I go, so let me know if I'm way off-base, but it seems like changing one of these caps might have an effect on the horizontal squeezing I'm seeing near the edges of the picture. I'll want to see about testing these ones, too; I know film caps aren't supposed to degrade like electrolytics, but I suppose it couldn't hurt to make sure they're on-spec.

I realize I'm straying a bit from the topic of RGB modding; is there a thread already that's better suited for this discussion? Or should I maybe make a new one?


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 Post subject: Re: TV RGB mod thread
PostPosted: Wed May 19, 2021 2:55 pm 


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matt wrote:
Have you seen a consumer TV where this is the case?


I own at least one set with either a variable capacitor or inductor for linearity. Can't check it's in storage, but doesn't seem to matter for this anyway.

Socks, I don't think I can help anymore. My analog electronics isn't strong enough to tell you what value to adjust. I think I would at least make sure the existing components are close to their stated values though. Anything in that section would make a huge difference if it's more than 20% out of spec. Often times film caps in the horizontal are rated for even less (5 or 10%).


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 Post subject: Re: TV RGB mod thread
PostPosted: Wed May 19, 2021 7:39 pm 


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maxtherabbit wrote:
matt wrote:
maxtherabbit wrote:
Sometimes the linearity coil is adjustable


Have you seen a consumer TV where this is the case?

come to think of it, no :P


Yup, me neither. Some of them would benefit from it, too - this might be a good thing to experiment with.

I have a couple of TVs that don't even have a linearity coil to begin with!


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 Post subject: Re: TV RGB mod thread
PostPosted: Fri May 21, 2021 12:33 am 



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I have RGB modded a Toshiba MV19N2C (year 2003). I have the service manual available.
Micon M61250FP
Chroma OEC7083A

I do not know the voltage coming from the Micon and furthermore, the ground resistor (5.6K) has a much higher capacity than the inline resistor (2.2k), so I could not figure out the voltage divider calculation to work. I connected directly the 0-0.7V to the Chroma RGB In pins (21/22/23).

I initially grounded the RGB signal with 75-ohm resistors, but I would not get any image.

Then I removed the 75-ohm resistor and I got an image. It is saturated though. Actually the red is either red or none, the same applied for green and blue. I tried to play around with the ground resistor. Anything below 200-ohm the image would not display. Anythin above the image would display saturated.

Is it a digital RGB signal?

Here below is the schematic and PCB:
Micon M61250FP
Image

Chroma OEC7083A
Image

Depending on the blanking voltage applied on PIN 24, it seems the chroma chip is behaving differently. I injected 5V straight. I wonder if there is not a way to play with the voltage level so to get the Chroma to accept analog signal. I modded recently a Toshiba 27AF46 following Segaholic youtube video and there was a similar chroma chip with input for either digital RGB or analog RGB
Image


Can this TV be modded?

Thx for your help.


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 Post subject: Re: TV RGB mod thread
PostPosted: Fri May 21, 2021 1:20 am 


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Try adding clamping caps and following this picture correctly.

Image


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 Post subject: Re: TV RGB mod thread
PostPosted: Fri May 21, 2021 2:13 am 



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Syntax wrote:
Try adding clamping caps and following this picture correctly.


I have seen and used this method and calculation for a Samsung TV that I modded last year. In this case though the ground resistor is larger than the inline resistor so assuming 5V from the OSD, the output voltage is 3.6V. I can't do much with my 0-0.7V VGA signal. So that is why decided to inject straight to the Chroma chip.

I continue digging and although the Chroma accepts either analog or digital RGB, I am afraid that it was programmed for Digital RGB. Looking at the Chroma chip documentation the I2C Bus table can be set to either Analog OSD =0 or 1. Is there a way to reprogram that? Would it make sense to do so? or should I just ditch this TV (I hate to do that).


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 Post subject: Re: TV RGB mod thread
PostPosted: Fri May 21, 2021 2:50 am 


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The lack of clamping caps kinda made me feel the same way re digital OSD.


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 Post subject: Re: TV RGB mod thread
PostPosted: Fri May 21, 2021 6:59 am 



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shikikanzero wrote:
Nope, looks all good there, but how are you getting it to blank? I'm working on this same set and can't get it to blank for some reason. Did some sets come with the PIP header left active and some didn't? There's a jumper at the front of the unit for PIP, does that need to be jumpered?

EDIT - Nevermind, i'm stupid. Actually LOOKED at the circuit this time and saw those missing resistors between the header and the jungle. Of course it wouldn't blank if there's no path lol

So it looks like those resistors (between the header and jungle IC) are required, good thing I took the liberty of installing them as a first step. I tested my blanking by applying 3V and 4.5V on the YS pin on the header via a 3xAA battery holder (for testing at 3V, I replaced the third battery with a wire). I haven't checked to see if my set has the PIP jumper on the front panel controls, but since it isn't equipped with a PIP feature, I would guess that it doesn't.

I'll be ordering the rest of the parts soon so I can work on RGB modding this Sony TV.

EDIT: After taking a second look at both the service manual and the blanking diagram for the mod, I've mistakenly routed the switch to the Standby 5V regulator (IC601). I've changed that to the set's normal 5V regulator (IC604) to be safe.

Since the parts have arrived recently, I might look into working on this mod on Monday, depending on how the day goes.


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 Post subject: Re: TV RGB mod thread
PostPosted: Mon May 24, 2021 2:22 pm 



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Hi I have small tv Roadstar CTV-1010XKT. This tv have scart connector but RGB and S-Video is disconnect. My question is... Possibile maybe is installation info this tv RGB mod and if is possibile how make this mod? If is possibile i have install also Component and S-Video to this connector.
In link below is service manuał for this tv:
https://elektrotanya.com/roadstar_ctv-1010xk-xkt.pdf/download.html
And at last my question is. Tv is for Europe, have scart, and Jungle IC supports RGB and S-Video signal. So why the hell were these signals not wired up in the design of the pcb to this tv?
P.S. Sorry for my terrible english


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 Post subject: Re: TV RGB mod thread
PostPosted: Mon May 24, 2021 5:20 pm 


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Kingbuzzo wrote:
I've come across a KV-27TS27 (service manual)
It's an older set from 1991 with an LN-1 Chasis

No luck finding an original datasheet for the TDA 3569B Jungle IC
NTE7048 NTSC Decoder w/Fast RGB Blanking is listed as its equivalent (Datasheet)

There's no RGB input listed for this IC. Instead a Y and C in.

An RGB OSD out is listed from IC101


For what it's worth I just successfully modded this set. I took my sync signal and attached it to pin 28 of the TDA8302 (which is labeled in the datasheet as sync separator input). This will define the horizontal and vertical blanking. Then I attached my color signals directly to the neck board. The color signals should be at appropriate 75ohm levels already. I'm giving up OSD contrast and brightness controls, but was able to tune this to looking pretty good adjusting the Screen and Sub brightness pots on the neck.


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 Post subject: Re: TV RGB mod thread
PostPosted: Tue May 25, 2021 6:53 pm 



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Hey guys, me again, asking for some advice, so anyway, i found another smal set wich im craving to use on a smal arcade, and after finding the manual here https://elektrotanya.com/panasonic_ct-z21s4,ct-z21r4,ct-z14r4_ch_na6lv_sm.pdf/download.html
Seems that this set would take rgb mod even though it does not have composite but it does have the yellow video. Anyway , ive been thinking alot and ive been considering both methods, the mux method were acording to my understanding, you dont have to use a switch and you can use the menu without the need for the switch right? But to be honest i have scraped to many tvs allready trying to attemp that way, so im cosidering the regular way, where you just add .75ohms resistors terminated to ground, and add a switch to the blanking so you can control the 5v provided to blanking. Am i right? So ive been succesfull with the regular method once vs the mux method fail (my fail not the method) 5 times allready.
So iwas wondering if someone has some advice on the regular method, heres what i plan to do:
Acording to this picture of the manual, the set has 2.2k resistors and 2.2p caps, so i need to just replace those with .75omhs resistors and 0.1uf caps, resistors terminated to ground right?
Just add a switch betwen the blanking with the 5v source right? As i see the blanking has a 470ohms resistor, followed by a diode followed by a 2.2 cap followed by a 4.7 resistor, i get a little bit lost in here, should i left them in place? thanks for any advice/ help. Have a great day.
Spoiler: show
Image

Spoiler: show
Image


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 Post subject: Re: TV RGB mod thread
PostPosted: Tue May 25, 2021 9:13 pm 



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FantasticMrSocks wrote:
I had a look at the service manual and inside the TV, and can confirm that the linearity coil is not adjustable. After some reading, though, it looks like my problem is with S-correction rather than linearity. Best I can tell, S-correction is handled by one or more of the film caps in the horizontal deflection circuit.
Spoiler: show
Image

I'm learning this as I go, so let me know if I'm way off-base, but it seems like changing one of these caps might have an effect on the horizontal squeezing I'm seeing near the edges of the picture. I'll want to see about testing these ones, too; I know film caps aren't supposed to degrade like electrolytics, but I suppose it couldn't hurt to make sure they're on-spec.

I realize I'm straying a bit from the topic of RGB modding; is there a thread already that's better suited for this discussion? Or should I maybe make a new one?

Give this a read, should help you to understand how the circuit shapes the wave for proper linearity:
http://www.gradllc.com/IMAGES/LINEARITY.pdf

That said, it's very hard to determine whether it's an issue of the circuit or just the nature of this flat glass tube. I have many flat CRTs and while the horizontal linearity isnt perfect, it's still pretty uniform. I also have a non-flat model that exhibits an issue similar to yours.

So unless you have a similar or identical set, it's hard to say whether that specific brand had bad electronics or if it's a component that failed.


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 Post subject: Re: TV RGB mod thread
PostPosted: Tue May 25, 2021 11:59 pm 



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abispac wrote:
Hey guys, me again, asking for some advice, so anyway, i found another smal set wich im craving to use on a smal arcade, and after finding the manual here https://elektrotanya.com/panasonic_ct-z21s4,ct-z21r4,ct-z14r4_ch_na6lv_sm.pdf/download.html
Seems that this set would take rgb mod even though it does not have composite but it does have the yellow video. Anyway , ive been thinking alot and ive been considering both methods, the mux method were acording to my understanding, you dont have to use a switch and you can use the menu without the need for the switch right? But to be honest i have scraped to many tvs allready trying to attemp that way, so im cosidering the regular way, where you just add .75ohms resistors terminated to ground, and add a switch to the blanking so you can control the 5v provided to blanking. Am i right? So ive been succesfull with the regular method once vs the mux method fail (my fail not the method) 5 times allready.
So iwas wondering if someone has some advice on the regular method, heres what i plan to do:
Acording to this picture of the manual, the set has 2.2k resistors and 2.2p caps, so i need to just replace those with .75omhs resistors and 0.1uf caps, resistors terminated to ground right?
Just add a switch betwen the blanking with the 5v source right? As i see the blanking has a 470ohms resistor, followed by a diode followed by a 2.2 cap followed by a 4.7 resistor, i get a little bit lost in here, should i left them in place? thanks for any advice/ help. Have a great day.
Spoiler: show
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Spoiler: show
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AN5165K jungle, not sure why but the RGB inputs don't require caps.

This TV should be modded with OSD mux targetting RGB "grounding" resistors R611, R612 and R613 (at least I think so, schematic is poor). Should be a twist method just like 8 bit guy mod.

My resistor table suggests you replace the 680 Ohm resistors with 300 Ohm.

For blanking i would use the 8 Bit Guy method by lifting the leg of R065 that is closest to IC001 and using a SPDT switch.

If you've failed 5 times to use the mux method you might want to actually try and learn the concept. Google "Voltage divider", that's the only concept the OSD mux is using. Once you understand the simple concept you'll find it way easier to implement than the god awful OSD snip method.

Image
_________________
___________________________________________________
MarkOZLAD
OSD/External RGB Mux Diagram
OSD/External RGB Mux Resistor Value Table 0.7Vp-p : 0.5Vp-p

"Imagine toggle switch OSD modding a TV in 2019" - maxtherabbit


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 Post subject: Re: TV RGB mod thread
PostPosted: Wed May 26, 2021 12:28 am 



Joined: 29 Mar 2020
Posts: 49
MarkOZLAD wrote:
abispac wrote:
Hey guys, me again, asking for some advice, so anyway, i found another smal set wich im craving to use on a smal arcade, and after finding the manual here https://elektrotanya.com/panasonic_ct-z21s4,ct-z21r4,ct-z14r4_ch_na6lv_sm.pdf/download.html
Seems that this set would take rgb mod even though it does not have composite but it does have the yellow video. Anyway , ive been thinking alot and ive been considering both methods, the mux method were acording to my understanding, you dont have to use a switch and you can use the menu without the need for the switch right? But to be honest i have scraped to many tvs allready trying to attemp that way, so im cosidering the regular way, where you just add .75ohms resistors terminated to ground, and add a switch to the blanking so you can control the 5v provided to blanking. Am i right? So ive been succesfull with the regular method once vs the mux method fail (my fail not the method) 5 times allready.
So iwas wondering if someone has some advice on the regular method, heres what i plan to do:
Acording to this picture of the manual, the set has 2.2k resistors and 2.2p caps, so i need to just replace those with .75omhs resistors and 0.1uf caps, resistors terminated to ground right?
Just add a switch betwen the blanking with the 5v source right? As i see the blanking has a 470ohms resistor, followed by a diode followed by a 2.2 cap followed by a 4.7 resistor, i get a little bit lost in here, should i left them in place? thanks for any advice/ help. Have a great day.[spoiler]


AN5165K jungle, not sure why but the RGB inputs don't require caps.

This TV should be modded with OSD mux targetting RGB "grounding" resistors R611, R612 and R613 (at least I think so, schematic is poor). Should be a twist method just like 8 bit guy mod.

My resistor table suggests you replace the 680 Ohm resistors with 300 Ohm.

For blanking i would use the 8 Bit Guy method by lifting the leg of R065 that is closest to IC001 and using a SPDT switch.

If you've failed 5 times to use the mux method you might want to actually try and learn the concept. Google "Voltage divider", that's the only concept the OSD mux is using. Once you understand the simple concept you'll find it way easier to implement than the god awful OSD snip method.


Thank you kind mark, will try again and ill read some voltage divider stuff to understand a bit more.


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