TV RGB mod thread

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shikikanzero
Posts: 16
Joined: Sat Jan 02, 2021 9:33 am

Re: TV RGB mod thread

Post by shikikanzero »

Thanks for all the help you guys give for these mods, was able to complete my first mod on a Sharp, and it looks awesome!

Helping a buddy mod his 13" now, every seems like it has gone well, except i'm experiencing this issue where the mod input seems to have to warm up. It only does this on the mod input, not on either of the composite inputs. Power cycling the TV will make it need to warm up again, although power cycling the console or blanking will not cause the issue.

https://youtu.be/1RipmKRfDFw

I have the mod wired directly to the closed caption header, with the S board removed, and the only thing in the RGB circuit is a 1kohm trimpot. So no capacitors or terminating resistors. 5v from console direct to YS for blanking. I see on the 2 board that there are a couple more components between the S board output and the jungle input, like the 10uf caps, 4.7k resistors in series or the 820 ohm ground terms.

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While the picture does look great as it is, can someone explain if I need to figure out how to mux those components, and why, if the lack of them is causing the issue, they are necessary, just as kind of a learning experience.
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Pikkon
Posts: 118
Joined: Tue May 26, 2015 6:25 am
Location: Florida

Re: TV RGB mod thread

Post by Pikkon »

Think I modded this exact model for rgb.

On mine I didn't have any components from the rgb inputs to the close caption decoder board,I added 0.1 caps and 75ohm resisters,for blanking I just used 5v from the tv.
abispac
Posts: 73
Joined: Sun Mar 29, 2020 3:44 am

Re: TV RGB mod thread

Post by abispac »

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-z ... nload.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.
Tv has some flyback issues,damnit ,seems ill never get a 13/14 inch monitor....
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Osirus
Posts: 214
Joined: Tue Jun 16, 2020 8:51 pm

Re: TV RGB mod thread

Post by Osirus »

Had a weird thing happen with a BA-5 Trinitron I RGB modded a while back. The RGB has worked fine, but for the first time since doing the mod I went back and tried to use Component (I did a toggle switch mod using the Component-in for sync). When I turned on the TV the screen never came on. Nothing worked until I disconnected the component cable. Then the TV came on again but was completely reset. All service menu adjustments were cleared and it was displaying the initial setup OSD.

When I reconnected component the TV locked up again. The OSD was displaying "VIDEO 4" before plugging it in, and continued to do so afterwards, but the input button did nothing. It was froze on Video 4 with nothing else displayed. The TV just locks up. It does this if it's connected to anything using component cables. What ever it's connected to doesn't even have to be turned on with a signal being output. It did it with a Mister and an RPi 3 w/Retrotink Ultimate without even being plugged in. So just being connected to something via component causes the lockup. The only think I can think of that would cause that it some kind of impedance issue.

Has anyone ever seen this before?

Update: Figured it out. When I reassembled after the mod I was highly intelligent and connected one of the jumpers going to the MA board into the wrong connector.

This TV's geometry sucks though.
JohnnyMax
Posts: 1
Joined: Tue Jun 01, 2021 1:27 pm

Re: TV RGB mod thread

Post by JohnnyMax »

Hi all,

I have a couple of NEC tv's that I'd like to RGB mod to use in a pair of arcade cabs I have & was hoping someone could help.
First is a NEC 59V80 which has a Toshiba TB1226EN & a Mitsubishi M37212M8.
Second is a NEC FS-6391 which has a Mitsubishi M52778SP & a M37220M3.

For the NEC 59V80 I found a guide which mods a JVC TM-A140PN which has the Toshiba TB1226EN.
https://immerhax.com/?m=201902

Any help on either of these TVs would be greatly appreciated.
abispac
Posts: 73
Joined: Sun Mar 29, 2020 3:44 am

Re: TV RGB mod thread

Post by abispac »

Shoot, i found a sony trinitron KV-27S42, just like the one MARKOZLAD documented here
viewtopic.php?p=1342960#p1342960
Ive seen a couple of sucesfull mods, made, and i surely could use a 27 inch rgb screen to make a tekken 5 arcade cabinet type
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so ill keep my fingers crossed, this time ill test the tv first before bringing it hope to avoid trying to mod a non working tv LOL
Thanks MarkozLad for documenting this one, it seems retarded eazy so i hope i dont screw up this time, im still loking to mod a 13/14 inch set.
Spoiler
MarkOZLAD wrote:Whilst I'm documenting Sony mods, here are the design diagrams I made for John M on the CRT Collective to mod his Sony KV-27S42 TV with BA-4D chassis using the OSD Mux method. He implemented it with great success.

This was done when I was still using diodes.

The basic process is:
- remove the existing inline throughole resistors R025, R026 and R027
- replace each of them with a 2K4R and a 1n4148 diode
- remove surface mount resistors R086, R087 and R088
- On the external RGB lines use 75R terminations to ground and then 430R inline
- Connect the external RGB lines to the leg of the diodes closest to the jungle
- Connect 5V to switch the switch to 1KR and solder after the existing R028 inline resistor on the blanking circuit

The theory behind the mod exactly the same as for the BA-5D, just a bit easier to implement because of the throughole resistors R025, R026 and R027.

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If you wanted to drop the diodes you could use 330R on the External RGB lines.

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Or even use 1000R/100R..

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https://www.svideo.com/bnc-sv-fm.html?f ... a2YJAO1zfo

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Some other things of note from this mod:

- John was originally using a purchased sync cleaner and couldn't get the TV to sync, he removed this from the setup and it worked
- John purchased an RCA to S-Video adapter and fed sync into S-Video. He said this fixed the image shifting you normally see.
abispac
Posts: 73
Joined: Sun Mar 29, 2020 3:44 am

Re: TV RGB mod thread

Post by abispac »

Here she is, and it turns on, so i might have a chance this time LOL
Bought everything today, but i couldnt find 2.4 resistors , they only had 2.5k and also instead of .430 they had .470, will they work the same?
Thanks for any advice.
Spoiler
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abispac
Posts: 73
Joined: Sun Mar 29, 2020 3:44 am

Re: TV RGB mod thread

Post by abispac »

So i have instaled the resistors together with the diodes, and the switch, and acording to this
Tengugurl wrote:If you are getting a black screen and it only shows if you have the menu button pushed, solder to pin 49 of IC001, take the 1k resistor off and it should work.
Also, make sure you blank when you toggle (Aka if there is a change, good, if there is not, you don't have a solid 5v+ connection)
Ive also have soldered the blanking to the pin 49 and the 5v to the 5v on the side of the tuner. The part im missing is , wich 1k resistor i have to remove?
Please if anyone is kind enough to directme in the right direction ill really apreciate it. Thanks.

Edit: Nevermind, found it on MARKOSLAD notes original topic, thanks. R028
grumblegore
Posts: 10
Joined: Thu Jun 03, 2021 6:13 am

Re: TV RGB mod thread

Post by grumblegore »

I just got hold of a kv-20s90 to practice with, and today I picked up a trinitron which the owner trying to discard described as a 32". I couldn't know at the time that in reality it is a kv-27s42. and I feel like I could not be more lucky that they're both the same BA-4D chassis. I've never done any work inside the TV before but I've got about two dozen hours into research on the topic and feel good about doing RGB mods on them this weekend.

With that, I just wanted to make sure I'm crystal clear in understanding Mark and a couple of comments he's made over the last couple years on this thread, tying it all together...
MarkOZLAD wrote:This was done when I was still using diodes.
Should I take this to mean that it's not necessary or maybe even advisable to use diodes? Is there any advantage or disadvantage (other than a possibly superfluous component)? I can source 330R resistors instead of the 430R for inline instead if that's the more modern best practice.

Also, later in this thread, Mark advised the 8-bit guy and prefers that switching method. I'm understanding that based on the diagrams here and on that video, you would pull up the leg of R028 facing the jungle and wire it to the empty pole of the switch to avoid pushing 5V into IC001?

If there's a method I missed for this chassis that allows for overlay of the actual OSD while using the RGB input (as it looks like with the switching, the OSD is straight severed while the RGB is toggled, I understand that would be significantly more complicated but I'd love to see that. If it's right here in this thread and I overlooked it, my bad.
mgerety
Posts: 54
Joined: Tue Nov 06, 2018 2:24 pm

Re: TV RGB mod thread

Post by mgerety »

Hey everyone,

I'm looking to mod an RCA ColorTrak, Chassis 177AM2. I've gotten a copy of schematics and a training manual for the set..

Here's what I've got:
Spoiler
Image
Spoiler
Image
I'm unclear on how these transistors affect the RGB mod. Here's the text from the training manual regarding these connections:
Later production sets that support closed caption decoders use red, green and blue
outputs from U3101 (pins 19, 18 and 17) to drive the red, green and blue OSD inputs
on U1001 (pins 40, 41 and 42) producing a full color OSD. Q2702, Q2701 and Q2703
buffer the red, green and blue signals and capacitively couple them to pins 40, 41 and
42 of U1001 respectfully.
Note: I've verified all of the resistances on-board with a multimeter.


Based on the main diagram, it APPEARS that R3317, R3319, and R3321 are grounding resistors -- these are 120ohm.

It looks like the main inline resistor is R3310,R33318, R3320 -- which are 1K ohm .
There's also another resistor inline (100 ohm)( R2713, R217, R2715)

Do I treat this like normal, use 1000ohm as the resistor value, and inject on the leg furthest away from the chip on the 1uf caps?
Do I count that 100ohm inn series?
Do I remove the 120ohm grounding resistors?
How does the transistor affect what I'm doing here? Also, the voltages going INTO these chips seem high (5.4 v) but it looks like at the leg of the transistor going to the 1uf caps it's .7v -- which is normal for mods, which is why I was thinking I should inject on the outer legs of those caps.

Any help here would be hugely appreciated. THanks in advance.

Any help would be huge.
Last edited by mgerety on Thu Jun 03, 2021 9:20 pm, edited 1 time in total.
abispac
Posts: 73
Joined: Sun Mar 29, 2020 3:44 am

Re: TV RGB mod thread

Post by abispac »

mgerety wrote:Hey everyone,

I'm looking to mod an RCA ColorTrak, Chassis 177AM2. I've gotten a copy of schematics and a training manual for the set..

Here's what I've got:
Spoiler
Image
Image
I'm unclear on how these transistors affect the RGB mod. Here's the text from the training manual regarding these connections:
Later production sets that support closed caption decoders use red, green and blue
outputs from U3101 (pins 19, 18 and 17) to drive the red, green and blue OSD inputs
on U1001 (pins 40, 41 and 42) producing a full color OSD. Q2702, Q2701 and Q2703
buffer the red, green and blue signals and capacitively couple them to pins 40, 41 and
42 of U1001 respectfully.
Note: I've verified all of the resistances on-board with a multimeter.


Based on the main diagram, it APPEARS that R3317, R3319, and R3321 are grounding resistors -- these are 120ohm.

It looks like the main inline resistor is R3310,R33318, R3320 -- which are 1K ohm .
There's also another resistor inline (100 ohm)( R2713, R217, R2715)

Do I treat this like normal, use 1000ohm as the resistor value, and inject on the leg furthest away from the chip on the 1uf caps?
Do I count that 100ohm inn series?
Do I remove the 120ohm grounding resistors?
How does the transistor affect what I'm doing here? Also, the voltages going INTO these chips seem high (5.4 v) but it looks like at the leg of the transistor going to the 1uf caps it's .7v -- which is normal for mods, which is why I was thinking I should inject on the outer legs of those caps.

Any help here would be hugely appreciated. THanks in advance.

Any help would be huge.
please use the spoiler option with your images.
retromaniak
Posts: 45
Joined: Wed Dec 26, 2018 9:51 am

Re: TV RGB mod thread

Post by retromaniak »

Hi, i own small Roadstar CTV-1010XKT TV, it has SCART connector, although it only has composite signal plugged in. So i have a question, Is it possible to make an RGB mod and optional connecting S-Video signal? If it's possible what kind of capacitors, resistors etc. do i need? I'm attaching link to the service manual of the TV.
https://elektrotanya.com/roadstar_ctv-1 ... nload.html
MarkOZLAD
Posts: 1004
Joined: Thu May 18, 2017 12:39 pm

Re: TV RGB mod thread

Post by MarkOZLAD »

mgerety wrote:Hey everyone,

I'm looking to mod an RCA ColorTrak, Chassis 177AM2. I've gotten a copy of schematics and a training manual for the set..

Here's what I've got:
Spoiler
Image
Spoiler
Image
I'm unclear on how these transistors affect the RGB mod. Here's the text from the training manual regarding these connections:
Later production sets that support closed caption decoders use red, green and blue
outputs from U3101 (pins 19, 18 and 17) to drive the red, green and blue OSD inputs
on U1001 (pins 40, 41 and 42) producing a full color OSD. Q2702, Q2701 and Q2703
buffer the red, green and blue signals and capacitively couple them to pins 40, 41 and
42 of U1001 respectfully.
Note: I've verified all of the resistances on-board with a multimeter.


Based on the main diagram, it APPEARS that R3317, R3319, and R3321 are grounding resistors -- these are 120ohm.

It looks like the main inline resistor is R3310,R33318, R3320 -- which are 1K ohm .
There's also another resistor inline (100 ohm)( R2713, R217, R2715)

Do I treat this like normal, use 1000ohm as the resistor value, and inject on the leg furthest away from the chip on the 1uf caps?
Do I count that 100ohm inn series?
Do I remove the 120ohm grounding resistors?
How does the transistor affect what I'm doing here? Also, the voltages going INTO these chips seem high (5.4 v) but it looks like at the leg of the transistor going to the 1uf caps it's .7v -- which is normal for mods, which is why I was thinking I should inject on the outer legs of those caps.

Any help here would be hugely appreciated. THanks in advance.

Any help would be huge.

I would be tempted to remove Q2701, Q2702 and Q2703. For each of these resistors, bridge the pads from Base to Emitter. Then I would remove R2712, R2716, R2714.

This should give us an OSD circuit like we are used to.

I would then do an OSD mux on R3317, R3319 and R3321.

I might remove and bridge R2713, R2717 and R2715 but it's unlikely to be necessary.

I can't seem to find a datasheet for LA7610.

I can't guarantee this will work but it's what I'd be doing.
___________________________________________________
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
abispac
Posts: 73
Joined: Sun Mar 29, 2020 3:44 am

Re: TV RGB mod thread

Post by abispac »

So i had succes with this sony trinitron KV-27S42 thanks to MarkosLad documentation and others experiences. What worked for me was, beside all the basic instructions, as i had black screen at the end of the mod was using blanking 5v to diode d003, removed resistor r028 thats near that same diode, and grabing 5v from near the tuner.

This set has some overscan issues, wich i hope i can fix via the secret menu, i still need to find me a remote control, this set looks so great. Pictures on my crappy camera wont show what really looks like.
againg thanks everyone here for keeping this alive.

My crappy setup, a cocktail cab ticrt and pc with emudrivers
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Full Galery here.
Spoiler
Disco Dan
Posts: 1
Joined: Wed May 26, 2021 3:38 am

Re: TV RGB mod thread

Post by Disco Dan »

Hi all.

Been lurking for a while, building up the courage to actually attempt this, and I think I'm basically ready. And by ready, I think I'm mentally ready to try to tackle this, but I still feel like there's a big gap in my understanding of how to do this so that I don't just end up ruining a perfectly good CRT. My biggest blind spot is not understanding when to use a capacitor or resistor. I understand the concept of these components, but not what they do in this use case, and not how to determine when and what kind to use (again, so I don't destroy the TV).

So my goal is to add a SCART port to the rear of this TV because I mostly use Nintendo consoles, and there are a plethora of SCART cables, as opposed to direct RGB cables. If someone thinks this is a bad idea, feel free to let me know.

Anyway, I have a Panasonic PV-1350W TV/VCR combo.

I've uploaded the manual here: https://www.discodan.org/stuff/pvc1320.pdf

From what I can tell, the meat is on page 63. The OSD chip (IC3301) sends RGB signals out from pins 19-21, and Blanking from 22. I notice a few resistors and capacitors on those lines which are both inline and go to ground (is that what everyone means when they say terminate?). Specifically the Green signal from the OSD has a ground termination (termination, right? I think I'm getting it) that the other two colors don't have. I don't know if any of this matters, because these all go to the Jungle IC, and somewhere between the OSD and the Jungle IC is where I want to splice my signal? But also need to send 5V to the blanking input of the Jungle IC?

This is where it gets murky for me and the whole reason I haven't attempted it on my own yet. I get the basic concept, but the specifics are evading me. I'm not sure where to inject, and whether or not I need new capacitors or resistors, based on the circuit for this particular model.

I also recently discovered that I may have been reading older threads, because apparently there's another process called OSD mux which I understand less than the other process. Ideally I'd like to be able to harness the native RGB signal in the TV but not completely lose the ability to see the on screen menu. I'm also 100% ok with a ghetto switch, but obviously would prefer to do it the "right way" so that it's not necessary to switch between OSD and RGB.

So the OSD RGB signal (Y is blanking, right?) goes from pins 19-21 to pins 29-27 of the Jungle IC (IC5301 / AN5368FB) and blanking goes from pin 22 of the OSD to 20 on the Jungle IC.

So somewhere between those two chips, I run three wires for R, G & B, and another wire for blanking to a +5V power supply? As I understand it, the ghetto switch turns that +5V on or off to toggle RGB and OSD.

I guess I should start with that mode first, but reading these posts, it seems there's another option which allows both the RGB input AND the OSD? So I could then change picture settings without constantly having to switch back and forth? I do have the remote, so I can get into the service menu if necessary.

I guess worst case, I just save up and get a $500 PVM, but this seems much more worthwhile and gratifying for the DYI aspect.

Sorry for the rambling first post. Any input and/or correction is super appreciated. Thanks for all you do!
grumblegore
Posts: 10
Joined: Thu Jun 03, 2021 6:13 am

Re: TV RGB mod thread

Post by grumblegore »

I've run into a problem with a mod on my kv-20s90 and I'm hoping there's some help here so I can resolve it before moving on to what I hope will be the star of the show - a kv-27s42 I want to mod when this first one is working.

First, here's the timeline album: https://imgur.com/a/4Jke8cm

I performed the mod referring mainly to MarkOZLAD's tutorial and Brigandier's success post. When I was initially finished strictly as per Mark's method, the output was pretty much the same as you can see in the album - all greyscale.

It's as if there were no color data at all on the RGB lines, or the TV isn't getting a signal to switch to a color mode and just using composite data. Plugging and unplugging the RGB lines, however, does impact the brightness of the greyscale image for the worse, so I know there's contact on those lines (I have also tested each line for continuity) even though they're not doing what they're supposed to. Toggling the switch in one direction or the other also has an effect which you can see in one of the images.

After the first failed test, I got back inside and added a 2.4kR after D003 (pictured) as Brigandier suggested, but that didn't result in any difference from the first test.

The input device:
  • Brand new MiSTer set up yesterday
  • IO board VGA with component_sync=1
  • The HDMI output to a monitor is fine
  • I don't currently have another RGB device to test with
I can't rule out that I have the MiSTer configured incorrectly, but I'd love a way to rule out the TV before I start messing with the FPGA device. After all, I haven't done anything weird to the MiSTer yet, but I've been all up into the guts of that TV and I'm much more likely to think there's a problem there I can solve, or at least test for.
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Osirus
Posts: 214
Joined: Tue Jun 16, 2020 8:51 pm

Re: TV RGB mod thread

Post by Osirus »

For MiSTer it's

composite_sync=1

Not component_sync. I speculate that it's only a mistake in your post and that your actual MiSTer settings are correct since what you are describing doesn't sound sync related. You don't have it mistakenly configured for YPbPr in your ini do you?
KPackratt2k
Posts: 211
Joined: Sun Apr 04, 2021 11:02 pm
Location: Seattle, WA, USA

Re: TV RGB mod thread

Post by KPackratt2k »

Good news, the Sony KV-20EXR20 TV has been successfully RGB modded. Here's a guide on how I've performed this mod for anyone who has a Sony TV with the ANU2 chassis (NOTE: for the KV-27EXR15/25, you will have to sacrifice Picture-in-Picture if you're modding that particular set).

Imgur gallery with mod schematics: https://imgur.com/a/vpUKca3
Service manual: https://elektrotanya.com/sony_anu2_chas ... nload.html

1a. (For KV-20/27EXR10/20) Add 4 100 ohm through-hole resistors into the R319-R322 sockets between the jungle chip and the PIP (A-31) header.

RGB Input diagram (for RCA/BNC connectors):
Spoiler
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1b. (For KV-27EXR15/25) Remove the A-31 header connector and desolder the leg of R319 that is closest to the header. The header will soon be replaced with a 4-pin Dupont header for your external RGB input.

2. Place a 150 ohm resistor in between R319 and a grounding pinhole on the A-31 header, this will lower your blanking voltage from 5V to a range that the jungle chip will accept (3V-4.5V).

3. Solder a wire on the 5V pin of the tuner (TP96A) and route it through a hole on the main board.

Blanking switch diagram:
Spoiler
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4. Solder a wire on the YS pinhole on the A-31 header, then solder a female 2-pin connector onto both wires for your blanking switch to connect.

5. Solder a 4-pin Dupont header onto Ground+RGB pinholes on the A-31 header. The YS blanking wire should be right next to your 4-pin header.

RGB header, YS wire and resistor placements:
Spoiler
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6. As directed in the RGB Input diagram, solder the negative ends of your 1uf capacitors on the input lines of your RCA/BNC RGB connectors and terminate them with 75 ohm resistors between the grounds and the input lines as you typically would in most TV RGB mods.

7. Solder 3 black wires onto the grounds of your RGB connectors, then solder the ends of your grounding wires onto another black wire. Add heat shrink over the soldered ends for protection.

8. Solder 3 colored wires onto the positive ends of the capacitors on your RGB connectors, then place a 4-pin Dupont connector onto the ends of your Ground+RGB wires. This connector will plug into the 4-pin header that you've soldered onto your A-31 header.

9. Solder 2 wires onto an SPST or SPDT switch and place a male 2-pin connector onto the ends of your wires, this will be connected to the blanking wires that you've soldered earlier.

10. Re-assemble the TV and test your new external RGB input.

Potential problems caused by incorrect mod installation and how to fix them:

If you're not seeing an image on the TV screen (e.g. you're getting a black screen without any text when you should be getting the text for your video input on the top-right corner of the screen), your RGB header cable is plugged in backwards. This should be fixable by unplugging your RGB header cable and plugging it in the opposite direction.

If your RGB image is (getting) dim or tinted in a weird way, you've most likely installed the capacitors in the opposite polarity or used bad capacitors. This should be fixable by reinstalling your capacitors in the correct polarity (in the case of the former) or replacing them with known good capacitors (in the case of the latter).

For best results, use the S-Video input on your Video 1 line to input your RGB sync via a BNC to RCA adapter plugged into an RCA to S-Video adapter. Using the Composite input for sync may shift the image to the left.

In my experience, all sync types (Sync-on-Composite, Sync-on-Luma, and 75 ohm CSync) should work perfectly fine for this mod. This may be dependent on how your consoles output the sync, so your mileage my vary.
Last edited by KPackratt2k on Sat Aug 07, 2021 6:57 am, edited 1 time in total.
MarkOZLAD
Posts: 1004
Joined: Thu May 18, 2017 12:39 pm

Re: TV RGB mod thread

Post by MarkOZLAD »

Apparently there is an issue with my blanking circuit in the document.

People are having more success by just wiring 5V direct to the diode without the 1K resistor.
___________________________________________________
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
grumblegore
Posts: 10
Joined: Thu Jun 03, 2021 6:13 am

Re: TV RGB mod thread

Post by grumblegore »

Osirus wrote:I speculate that it's only a mistake in your post and that your actual MiSTer settings are correct since what you are describing doesn't sound sync related. You don't have it mistakenly configured for YPbPr in your ini do you?
You're right, it was a typo. Too much lead solder fumes today. :D

Code: Select all

ypbpr=0
composite_sync=1
grumblegore
Posts: 10
Joined: Thu Jun 03, 2021 6:13 am

Re: TV RGB mod thread

Post by grumblegore »

MarkOZLAD wrote:Apparently there is an issue with my blanking circuit in the document.
Are you referring to the BA-4D doc? If so...
MarkOZLAD wrote:People are having more success by just wiring 5V direct to the diode without the 1K resistor.
...I can pull off the 1K.

I also put a 2.4K after that diode based on Brigandier's suggestion in his post on a mod for the same board revision, thinking I might be experiencing the same dimming problem he was, but there was no visible change. I wonder whether it would make sense to pull that off too while I'm in there. I'd basically be back to just the diode as it was on the board, with 5V switched in.
abispac
Posts: 73
Joined: Sun Mar 29, 2020 3:44 am

Re: TV RGB mod thread

Post by abispac »

grumblegore wrote:
MarkOZLAD wrote:Apparently there is an issue with my blanking circuit in the document.
Are you referring to the BA-4D doc? If so...
MarkOZLAD wrote:People are having more success by just wiring 5V direct to the diode without the 1K resistor.
...I can pull off the 1K.

I also put a 2.4K after that diode based on Brigandier's suggestion in his post on a mod for the same board revision, thinking I might be experiencing the same dimming problem he was, but there was no visible change. I wonder whether it would make sense to pull that off too while I'm in there. I'd basically be back to just the diode as it was on the board, with 5V switched in.
I dont follow exactly what you doing, but if the mod you are attempting is the same as the ba-4d, nowhere in the guides i saw said that you need a 2.4k resistor on the blanking, the mod is fair easy:
remove the resistors, wich aparently you allready did
replace the hole resistors with 2.4k and add the diodes there, make sure they are the correct position or way, wich you seem to did already.
at blanking, place on end to the 5v near the tuner and the other end on the top of the diode soldered point, that would be on the other side of the smal triangle not on the triangle. now, theres a very tiny 1k surface mounted resistor near the doo3 diode, you need to remove, is on the side of the diode, make sure not to damage the cap that is in there.

Solder the proper rgb cables at the of the diodes you soldered first together wit the 2.4k resistors.
And at the end of those signal cables, solder the 430ohms resistors,i didnt had 430 so i did mine with a 330+100ohms and it worked the same,anyway then a piece of cable of the proper color cable, then a 75ohms resistor, and that would be where you will input your signal, after that , make sure to terminate the 75ohms resistors to ground, what i did i just twisted all together (the end of the 75ohms resistors) and use a single cable directly to the ground of the video signals on my computer. Im using a pc with emudriver. To make sure, i also soldered a ground from the tv and added that to the ground side of the 75 ohms resistors.

turn on your rgb signal aparatus, turn on the tv, and turn your blanking switch, all should work.
so my point is, there is no 2.4k resistor on the blanking.
Pardon my bad english i do my best. but im exited that this mod was stupid easy and allthough it didnt work at first, i just looked for the correct blanking point and all worked flawesly...very nice.
good luck.
Brigandier
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Re: TV RGB mod thread

Post by Brigandier »

abispac wrote:I dont follow exactly what you doing, but if the mod you are attempting is the same as the ba-4d, nowhere in the guides i saw said that you need a 2.4k resistor on the blanking, the mod is fair easy...
Not all BA-4D are equal, the 2.4k resistor he's referring to is in my post/experience with BA-4D here: viewtopic.php?p=1449666#p1449666
abispac
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Re: TV RGB mod thread

Post by abispac »

Brigandier wrote:
abispac wrote:I dont follow exactly what you doing, but if the mod you are attempting is the same as the ba-4d, nowhere in the guides i saw said that you need a 2.4k resistor on the blanking, the mod is fair easy...
Not all BA-4D are equal, the 2.4k resistor he's referring to is in my post/experience with BA-4D here: viewtopic.php?p=1449666#p1449666
Well, now he has 2 options, hope one of them will work for him. On my set , although i still have to find me a remote control, i wonder, how to use the svideo for sync, as im currently using the composit output for sync, so i have a bit of overscand ot the left and to the bottom. I cant seem to find how you guys use that, i dont mind soldering the cables direclty, i jus need to know wich ones to use, if anyone has some advice for this poor soul, thanks alot.
grumblegore
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Re: TV RGB mod thread

Post by grumblegore »

My kv-20s90 BA-4D is now "done." I added two pictures to the end of the original album to demonstrate success! I'm going to add a new reply with the remaining problem to make it "DONE done."

Updated instructions, which worked for my TV specifically, modified slightly from MarkOZLAD's original:

- remove the existing inline throughole resistors R025, R026 and R027
- replace each of them with a 2K4R and a 1n4148 diode
- remove surface mount resistors R087, R088 and R089
- On the external RGB lines use 75R terminations to ground and then 430R inline
- Connect the external RGB lines to the leg of the diodes closest to the jungle
- Pull 5V off Q650 (e) and solder to the one of the outside poles on your switch
- Connect a wire from the middle pole of your switch and solder after the existing R028 inline resistor, at the incoming leg of D003, on the blanking circuit
MarkOZLAD wrote:People are having more success by just wiring 5V direct to the diode without the 1K resistor.
Add me to the list of those people. I removed that resistor (and the 2.4k I had put in line after D003), and it works fine now!
Brigandier wrote:
abispac wrote:I dont follow exactly what you doing, but if the mod you are attempting is the same as the ba-4d, nowhere in the guides i saw said that you need a 2.4k resistor on the blanking, the mod is fair easy...
Not all BA-4D are equal, the 2.4k resistor he's referring to is in my post/experience with BA-4D here: viewtopic.php?p=1449666#p1449666
This is exactly a correct statement. My BA-4D did not require the 2.4kR after D003 and I'm not sure if it impacted the outcome or not, but it's working fine now without it.
grumblegore
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Re: TV RGB mod thread

Post by grumblegore »

Regarding my completed kv-20s90 mod, now I want to fix the picture.

As you can see from this image:
Spoiler
Image
I have convergence issues (blue is the worst) and what I think I heard Mark refer to as "jail bars". These issues existed before my mod purely over component video on a 1st gen Raspberry Pi, so I'm sure they weren't introduced in the process of adding RGB (though it's definitely possible I bumped something that made them a little worse, but I can't determine that) and now I just have to learn how to tune them.

I'm going to scour this thread for advice on cleaning those up, but if anyone has pointers (this thread has gotten a bit dense), I'd love to look at them.
Brigandier
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Re: TV RGB mod thread

Post by Brigandier »

grumblegore wrote:This is exactly a correct statement. My BA-4D did not require the 2.4kR after D003 and I'm not sure if it impacted the outcome or not, but it's working fine now without it.
Congrats on the success. Looking through your album, I see you also have a jailbar issue. I had this as well, and it went away when I positioned the mod wiring away from the flyback (or maybe I moved it from something else that was causing it, seemed to be the cause to me). Hope that helps.
grumblegore
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Re: TV RGB mod thread

Post by grumblegore »

Brigandier wrote:Congrats on the success. Looking through your album, I see you also have a jailbar issue. I had this as well, and it went away when I positioned the mod wiring away from the flyback (or maybe I moved it from something else that was causing it, seemed to be the cause to me). Hope that helps.
Thanks man, I'll look at rerouting the wiring when I get in there to deal with the convergence.

I have much different plans for the larger set that I'm hoping to make my daily driver for my kids. I'm going to employ T-Taps where the mod wiring connects to the 2k4R+diode at the board, and I'm getting some JST SM connectors and a crimping tool so I can do a leveled up job that won't raise the ire (as much) of someone with skills who opens the TV years from now.

You can see I used that ribbon cable, which I don't necessarily regret. However, the gauge of the wire is ludicrous tiny, like 26 AWG and not really fun to work with and i'd prefer not to unless required for a particular application. I have some spools of 20 AWG that is a million times easier to work with, and if I could have built my own cables, I would have done that for sure. I only learned about JST SM connectors yesterday after going down the rabbit hole past the LED strips. I can't find any better options for male / female connectors myself so far, but I'm open to suggestions.

I mean, ideally everything (including the connectors) would just be on its own little PCB, and screwed down relative to the mainboard rather than into the plastic of the chassis, but I think that's more engineering than most of us want to do on these sets. Barring that, there aren't a lot of options that allow access to the guts after the mod is done.
grumblegore
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Re: TV RGB mod thread

Post by grumblegore »

abispac wrote:i wonder, how to use the svideo for sync, as im currently using the composit output for sync, so i have a bit of overscand ot the left and to the bottom. I cant seem to find how you guys use that, i dont mind soldering the cables direclty, i jus need to know wich ones to use, if anyone has some advice for this poor soul, thanks alot.
So I looked at the female BNC to male s-video adapter on offer at svideo.com. I even had it in my cart but it really hurts my soul to pay nearly $30 after shipping for a single "cheap" connector. It's true what they say, when you're the only game in town you can charge whatever you want for admission. I couldn't find another such adapter anywhere after about a half hour of google searching.

However... what might help you (and this is my plan, just ordered one myself) is to just get a female RCA to male s-video adapter for $8 on Amazon. If you're getting sync from composite right now, I have to ASSUME that you can plug your composite end into this and pull sync from s-video this way for a lot cheaper than the other option. Obviously there is some question / mystery as to how the cable is built internally, but there's not a lot of mistakes to make on something like this, and it's long enough that if you have to open it up and put a new end where the RCA is, you can do that.

It will be a while before I have my larger mod with the s-video port done, but when it is, I'll report back how this cable worked for me.
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matt
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Re: TV RGB mod thread

Post by matt »

grumblegore wrote:Regarding my completed kv-20s90 mod, now I want to fix the picture.

As you can see from this image:
Spoiler
Image
I have convergence issues (blue is the worst) and what I think I heard Mark refer to as "jail bars". These issues existed before my mod purely over component video on a 1st gen Raspberry Pi, so I'm sure they weren't introduced in the process of adding RGB (though it's definitely possible I bumped something that made them a little worse, but I can't determine that) and now I just have to learn how to tune them.

I'm going to scour this thread for advice on cleaning those up, but if anyone has pointers (this thread has gotten a bit dense), I'd love to look at them.
These jailbars are common in Trinitrons, and are usually caused by a bad capacitor in the power supply circuit. On the 20S90, the one that seems to be the usual culprit is C226 (4.7uF, 160v). While you're at it, it's a good idea to replace C553 and C1751 (both are 10uF, 250v) since these often go bad as well and cause screen brightness issues. These particular caps have been out of spec in a majority of Trinitrons that I've worked with and it does cause visible artifacts. Make sure to use low ESR/high ripple current caps, since they're under a lot of stress.
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