TV RGB mod thread

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retrogamer47658
Posts: 21
Joined: Sun Apr 23, 2023 5:16 pm

Re: TV RGB mod thread

Post by retrogamer47658 »

Quick look at the schematics:

Sync might be able to be injected into pin 42 (EXT_V_IN) of the jungle chip. It leads to an optional circuit for non-North American models that apparently included Audio and Video inputs.

The Audio inputs look like they connected to pin 51 (EXT_A_IN).
Awesome, thanks! I'll give this a try (when I have the time) and hopefully it should work.
rj005451@gmail.com
Posts: 1
Joined: Wed Apr 26, 2023 12:36 am

Re: TV RGB mod thread

Post by rj005451@gmail.com »

Hi does anybody know how to do a step by step guide to rgb mux a Sony trinitron 24fv10/4C-Chassis
https://elektrotanya.com/cgi-bin/download2.cgi?dk=0iiy92a8dk7d4l84adougw1gf2xd5u5xybep5xgd7z0u0ezd&fid=108450&file=sony_kv-24fv10_25fv10_c-ch.ba-4c_sm.pdf[url]
SkiDragon
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Joined: Sun Apr 30, 2023 10:46 pm

Re: TV RGB mod thread

Post by SkiDragon »

Has anyone had any luck modding Sanyo TVs for RGB? I picked up a free Sanyo DS27510. As is, it only has composite video input. I took out the control board to have a look, and although it is hard to read I believe the jungle chip is a LA76834N. I have never modded a CRT for RGB input and I cannot find a data sheet for this particular chip, but I ran across some comments saying that they had no luck on other Sanyo models.

If not, I will probably use it for NES games temporarily and then put it back up for sale/for free on craigslist/facebook/etc.

Thanks.
1nick9
Posts: 1
Joined: Mon May 01, 2023 10:42 am

Re: TV RGB mod thread

Post by 1nick9 »

hey gone to rgb mux mod this sanyo cp21sa1. thought had it sorted off the crt info page. well it works, but the blanking resistor is clearly wrong as shows the game only with menu up seen.
Image

this is the snap from the service manual.
Image

what came up with off crt database info (not in diagram is the 56p caps on rgb, i left them on however)
Image

just wondering if anyone be good enough to help me cal the blanking line setup :D the crtdatabase info is rather light and done as it has said.
Link040188
Posts: 3
Joined: Sat Nov 26, 2022 9:04 pm

Re: TV RGB mod thread

Post by Link040188 »

hey everyone so i wrapped up a rgb mod on a kv 27fs12. i followed the guide on crt database for the kv 27fs13 because it is the same chassis and everything was in the same place. the rgb works fantastic but now i have a magenta hue on composite and s/video inputs and green hue on component. if i flip my switch to turn on rgb the hue goes away but obviously i cant see anything anymore because the switch is sending the 5v to the blanking pin https://imgur.com/my8RHL7 https://imgur.com/pVBWbl4
KPackratt2k
Posts: 211
Joined: Sun Apr 04, 2021 11:02 pm
Location: Seattle, WA, USA

Re: TV RGB mod thread

Post by KPackratt2k »

rj005451@gmail.com wrote:Hi does anybody know how to do a step by step guide to rgb mux a Sony trinitron 24fv10/4C-Chassis
https://elektrotanya.com/cgi-bin/downlo ... sm.pdf[url]
Sorry for the late response, but since this is identical to the BA-4D chassis used on later curved Trinitrons, the instructions from these guides should apply to it. Each guide is different, so it's your decision on which approach you wish to take:

https://crtdatabase.com/crts/sony/sony-kv-27v42
https://sector.sunthar.com/guides/crt-r ... ba-4d.html

The grounding resistor locations differ depending on the screen size of the set, so it would be wise to cross-reference the service manual for your set to ensure that you remove the right resistors.

It's also possible to Component mod this chassis. You can do both mods through the use of a 3P3T switch:
https://shmups.system11.org/viewtopic.p ... 3#p1509713

(The resistor values for RGB were different because I referred to an older guide that involved changing the original OSD resistors. It's your call if you want to do it the way I did or use the resistor values from the other guides.)
retrogamer47658
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Joined: Sun Apr 23, 2023 5:16 pm

Re: TV RGB mod thread

Post by retrogamer47658 »

retrogamer47658 wrote:
Quick look at the schematics:

Sync might be able to be injected into pin 42 (EXT_V_IN) of the jungle chip. It leads to an optional circuit for non-North American models that apparently included Audio and Video inputs.

The Audio inputs look like they connected to pin 51 (EXT_A_IN).
Awesome, thanks! I'll give this a try (when I have the time) and hopefully it should work.
Hey guys, back again. I've got it working now! Sort of.

The main issue I'm still faced with is that I need some way to "awaken" the A/V inputs if I'm going to use EXT_V_IN and EXT_A_IN for the sync and audio respectively. I saw some discussion about reprogramming the EEPROM on page 141, and also some stuff about isolating the CVBS output. I'm leaning a bit more towards the EEPROM route, since the CVBS isolation sounds like it effectively disables the antenna input (could be wrong though). I could be overthinking it and there may just be an option in the service menu, but I don't think there is (link to the service manual: https://elektrotanya.com/daewoo_chassis ... nload.html). Anyone have advice on how to go about doing this?

Also, I think I messed up the blanking resistors; RGB only shows when the menu is on. I used a 3.9k in-line resistor (same as factory grounding) and a 75 ohm termination, but obviously that's not right. Any idea what I should change these to? Thanks!
KPackratt2k
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Location: Seattle, WA, USA

Re: TV RGB mod thread

Post by KPackratt2k »

SkiDragon wrote:Has anyone had any luck modding Sanyo TVs for RGB? I picked up a free Sanyo DS27510. As is, it only has composite video input. I took out the control board to have a look, and although it is hard to read I believe the jungle chip is a LA76834N. I have never modded a CRT for RGB input and I cannot find a data sheet for this particular chip, but I ran across some comments saying that they had no luck on other Sanyo models.

If not, I will probably use it for NES games temporarily and then put it back up for sale/for free on craigslist/facebook/etc.

Thanks.
Looks like it can be modded: https://sector.sunthar.com/guides/crt-r ... 27214.html
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Osirus
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Re: TV RGB mod thread

Post by Osirus »

retrogamer47658 wrote: Also, I think I messed up the blanking resistors; RGB only shows when the menu is on. I used a 3.9k in-line resistor (same as factory grounding) and a 75 ohm termination, but obviously that's not right. Any idea what I should change these to? Thanks!
The blanking line doesn't need 75 ohm termination. That's just for your inputs. The blanking line should involve a voltage divider that applies something around 2.5-3.5V to the blanking input on the jungle chip (typical, YMMV).
retrogamer47658
Posts: 21
Joined: Sun Apr 23, 2023 5:16 pm

Re: TV RGB mod thread

Post by retrogamer47658 »

More updates!

1) I got the composite inputs working! I read the service manual closely, specifically the pin functions for I701, the microcontroller. Apparently, the active input is decided by 5v on pin 1: 5v = TV (tuner) and 0v = VIDEO (composite). So, I disconnected pin 1 from the board, and voila! Pressing 'INPUT' on the remote now brings me to the 'LINE' (composite) input. Thankfully, this didn't completely disable the antenna input either, which was one of the main things I was worried about.

2) With the new composite input acquired, I realized that blanking resistors were fine from the beginning; it was being on the tuner input that was screwing stuff up. Now, the external RGB shows up when it should. However, it seems like I may have an issue elsewhere. Audio (injected into pin 51 on the jungle) works just fine, which is promising, but the video (injected into pin 42) is a mess. When the OSD is off, the video is incredibly blurry and partially distorted; all colors have mixed into an almost monochrome palette. Upon opening the OSD, however, these colors are (mostly) fixed, except for a slightly blue tint - but that can be adjusted in the service menu.

Even though the colors are corrected when the OSD is active, the video still seems off. There are various levels of 'waviness' and distortion that leads me to believe something's up with sync. Any thoughts about this/what steps to take next? Thanks for the help!
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Tempest_2084
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Re: TV RGB mod thread

Post by Tempest_2084 »

Does anyone know if a Toshiba CF2636 can be RGB modded? It's an older composite only set (1987) and has a 8650 chassis according to the back. The set is gorgeous (faux woodgrain and everything) and I'd love to be able to use my RGB modded systems on it.
Dr_Snugz
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Joined: Wed Aug 11, 2010 8:01 pm

Re: TV RGB mod thread

Post by Dr_Snugz »

Hello! I'm half way through an RGB mod for a Phillips Magnavox 19PR21 C122 but I'm stuck and could use some guidance.

I can't find a service manual for the set itself but I was able to locate manuals for the OSD chip: https://pdf1.alldatasheet.com/datasheet ... 72M6H.html and the jungle chip: https://pdf1.alldatasheet.com/datasheet ... 03CFP.html

With those manuals I was able to reverse trace the RGB inputs to jumpers on the board where I was able to inject the RGB signal from my SCART connector to the jungle chip but the picture is out of sync and I can't figure out where to wire up the composite sync from the SCART.

When the set is on the AV input I can see the desynced RGB output of my console where the characters from the OSD would normally be, and when I change to a channel on the tuner, I can see the full desynced picture but it won't accept the sync signal I'm trying to send to the composite port. When I wire composite sync to the RCA jack the TV just displays the composite video instead of the RGB.

I've successfully modded 3 sets before but this one has me stumped, does anyone know where I should be sending sync to get a stable picture? Thanks in advance.
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Edgecrusher
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Location: Michigan

Re: TV RGB mod thread

Post by Edgecrusher »

Ok! Found a new victom today! It's an Emerson CR202em9 20". It has flat glass but hits that sweetspot size for me. I'd guess this is a model that came out close when everything was starting to go HD as it has a stylized logo on the front that say "SDTV", and "Dolby Pro Logic".
What I'm wondering is if this isn't too digital for a mod which will make me really sad.

Here's the -matic for the main IC and I have colored the RGB lines coming out the top. My eye's tell me the OSD circuit is processed entirely inside the chip and I won't be able to inject my RGB anywhere. It appears these lines go straight to the neckboard (CRT CBA).

Let me know if I'm right, please. I can make more pics if neccessary
Image


Image

edit: the more I think about it, that resistor and diode look like the normal place to inject...?
KPackratt2k
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Location: Seattle, WA, USA

Re: TV RGB mod thread

Post by KPackratt2k »

Dr_Snugz wrote:Hello! I'm half way through an RGB mod for a Phillips Magnavox 19PR21 C122 but I'm stuck and could use some guidance.

I can't find a service manual for the set itself but I was able to locate manuals for the OSD chip: https://pdf1.alldatasheet.com/datasheet ... 72M6H.html and the jungle chip: https://pdf1.alldatasheet.com/datasheet ... 03CFP.html

With those manuals I was able to reverse trace the RGB inputs to jumpers on the board where I was able to inject the RGB signal from my SCART connector to the jungle chip but the picture is out of sync and I can't figure out where to wire up the composite sync from the SCART.

When the set is on the AV input I can see the desynced RGB output of my console where the characters from the OSD would normally be, and when I change to a channel on the tuner, I can see the full desynced picture but it won't accept the sync signal I'm trying to send to the composite port. When I wire composite sync to the RCA jack the TV just displays the composite video instead of the RGB.

I've successfully modded 3 sets before but this one has me stumped, does anyone know where I should be sending sync to get a stable picture? Thanks in advance.
It sounds like you didn't apply a blanking voltage. Follow the path between pin 27 of the M61203CFP (the jungle chip) and pin 39 of the M37272M6H (the microcontroller), there should be a grounding resistor and an inline resistor. In which case, simply lift the inline resistor on the side of the microcontroller and inject 5V with a variable resistor inline into it. This should fully blank the RGB picture and you can adjust the variable resistor to a safe spot to determine the value of your blanking resistor.

You should also inject sync into the Composite video input (or S-Video Luma input if your TV has an S-Video input).
titan91
Posts: 57
Joined: Sun May 14, 2023 1:44 pm

Re: TV RGB mod thread

Post by titan91 »

Hey guys, I have done a successful RGB mod before and would like some advice. I have a Philips/Magnavox TV, model number MT2501 with chassis number 25M800. I was unable to find a service manual for this TV or chassis, but it's an even more stripped down version of other models. Probably sold for less than $160. RF only with a single mono speaker. So adding RGB or component to this would make even more sense. Mine has a superior Samsung tube, since the Philips ones from this era have been known to have quality control issues. The picture is pretty nice.

So I took mine apart and found it has a combined video processor/microcontroller IC. The Philips TDA9587H. I also found the datasheet:

https://datasheetspdf.com/pdf-file/8705 ... TDA9587H/1

Had a hard time otherwise sourcing it. It has inputs for RGB that double as YUV, or YPbPr/component. I was wanting my mod to be component, not RGB, due to it being very common in America. Plus with PS2 DVD playback and many Wii games, RGB will often not work vs. component.

Is anyone familiar with this type of Philips video processor (jungle) IC? I also found this thread discussing a component video mod as well. I read about the possibility of using the service menu to enable factory disabled inputs. Not sure if that's possible with my chassis. I also have that blanking pin which maybe be used to enable that input.

http://forum.arcadecontrols.com/index.p ... msg1670256

Edit: Looks like some people have already gone down this rabbit hole with this IC. I'll need to catch up reading about that. There is hope!

https://shmups.system11.org/viewtopic.p ... 1#p1496031
Last edited by titan91 on Sun May 14, 2023 11:06 pm, edited 3 times in total.
retrogamer47658
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Re: TV RGB mod thread

Post by retrogamer47658 »

Alright, hopefully a final follow-up with this Portland that's been driving me nuts.

So I've figured out the sync/composite issues once and for all - turns out there was a grounding capacitor that was causing all that mess. Got rid of that, now it works fine. However, now that I've moved on to geometry and color adjustments, a few weird things are happening. For one thing, the RGB picture is EXTREMELY bright when first turning on the console. The brightness corrects itself given a minute or two, but that is obviously not normal behavior. This could still be related to composite though, as it doesn't occur on the tuner input.

Also, when the brightness is properly calibrated according to the 240p test suite Color Bars, geometry begins to become slightly distorted and the picture gets fuzzier. This could be a normal behavior, but when I turn it down to fix the geometry the Color Bars go completely black at around the 5-7 mark. This, in turn, affects the picture in a pretty clear way, so I don't think I can just leave it like that. Any help is appreciated, I would like to wrap this up as soon as possible. Thanks!

Quick edit: Ignore the 1st problem I mentioned, turns out I needed to adjust the User Menu contrast. Boy do I feel silly. The sudden increase in brightness still occurs though, any thought on that would be helpful. Thanks again!
titan91
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Re: TV RGB mod thread

Post by titan91 »

So I spent about an hour reading up on the Magnavox sets and it's my understanding that these RF only mono variants have different firmware that prevents the CVI YUV input from being enabled in the service menu. I've also read you can't even get into the service menu on some models without a factory remote. I have a remote for this on order and will try the service menu. But I'm not hopeful at this point.

So if that is the case, would disconnecting the jungle IC's RGB outputs and splicing in there be practical? The data sheet says these outputs are 2v peak to peak. Also, I would need to find a way to get sync into the IC. That may not be possible either if the system is firmware locked to accept only video IF and audio IF from the tuner.

The chassis model number does not match the format of numbers previously documented on successfully moddable sets either. I'll post an update when I get the remote.
Ikaruga11
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Re: TV RGB mod thread

Post by Ikaruga11 »

Is there anyone in Ohio who will RGB mod a consumer CRT as a paid service for me?
WaveAmbassador
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Joined: Wed May 17, 2023 4:01 am

Re: TV RGB mod thread

Post by WaveAmbassador »

Hi all, new to the forums but long CRT enthusiast , I have a RCA F26634SF Id like to RGB mod but the schematics/Service manual doesnt seem to exist. Any advice for how I can pull this off? I know I can look up my Jungle and Micom chip pinouts but thats only part of the puzzle, right? Thanks in advance :mrgreen:
Issac Zachary
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Joined: Mon Oct 23, 2017 2:54 pm

Re: TV RGB mod thread

Post by Issac Zachary »

WaveAmbassador wrote:Hi all, new to the forums but long CRT enthusiast , I have a RCA F26634SF Id like to RGB mod but the schematics/Service manual doesnt seem to exist. Any advice for how I can pull this off? I know I can look up my Jungle and Micom chip pinouts but thats only part of the puzzle, right? Thanks in advance :mrgreen:
I'd say start with that. If the chip doesn't have the pins you want (RGB in this case) then you know you can't do it. But if they do, then you can contemplate the next step. I wonder if simply signalling the blanking pin would be enough to prove it can switch to RGB.
WaveAmbassador
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Re: TV RGB mod thread

Post by WaveAmbassador »

Issac Zachary wrote:
WaveAmbassador wrote:Hi all, new to the forums but long CRT enthusiast , I have a RCA F26634SF Id like to RGB mod but the schematics/Service manual doesnt seem to exist. Any advice for how I can pull this off? I know I can look up my Jungle and Micom chip pinouts but thats only part of the puzzle, right? Thanks in advance :mrgreen:
I'd say start with that. If the chip doesn't have the pins you want (RGB in this case) then you know you can't do it. But if they do, then you can contemplate the next step. I wonder if simply signalling the blanking pin would be enough to prove it can switch to RGB.
I actually managed to get the Service manual but its kinda hard to decipher. it doesnt have block diagrams so its only schematics, and the video processing circuits are on like 4 different pages. if some here can help me mark it up that'd be insanely helpful. also dont understand where the 0.1uf caps come in, also what voltage on the caps should i use? sorry im a noob when it comes to the theory but i have soldering skills and such to do it

Here's the service manual: https://www.mediafire.com/file/s8gaafpp ... 1.pdf/file
Issac Zachary
Posts: 163
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Re: TV RGB mod thread

Post by Issac Zachary »

WaveAmbassador wrote:
Issac Zachary wrote:
WaveAmbassador wrote:Hi all, new to the forums but long CRT enthusiast , I have a RCA F26634SF Id like to RGB mod but the schematics/Service manual doesnt seem to exist. Any advice for how I can pull this off? I know I can look up my Jungle and Micom chip pinouts but thats only part of the puzzle, right? Thanks in advance :mrgreen:
I'd say start with that. If the chip doesn't have the pins you want (RGB in this case) then you know you can't do it. But if they do, then you can contemplate the next step. I wonder if simply signalling the blanking pin would be enough to prove it can switch to RGB.
I actually managed to get the Service manual but its kinda hard to decipher. it doesnt have block diagrams so its only schematics, and the video processing circuits are on like 4 different pages. if some here can help me mark it up that'd be insanely helpful. also dont understand where the 0.1uf caps come in, also what voltage on the caps should i use? sorry im a noob when it comes to the theory but i have soldering skills and such to do it

Here's the service manual: https://www.mediafire.com/file/s8gaafpp ... 1.pdf/file
It looks like the U3101 System Control chip does send an RGB signal to some "External RGB Matrix" chip that then converts the RGB signal into a Y-Pb-Pr signal which is then converted back into the RGB signal for the electron guns... Not ideal, but if you can figure out where that External RGB Matrix chip is and it's pinout you might be able to inject the RGB signal there and use the FSW line to switch to RGB.

TP2701, TP2702 and TP2707 look like service test points that go directly to that circuit, although they are after the capacitors, not before.
KPackratt2k
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Location: Seattle, WA, USA

Re: TV RGB mod thread

Post by KPackratt2k »

WaveAmbassador wrote:I actually managed to get the Service manual but its kinda hard to decipher. it doesnt have block diagrams so its only schematics, and the video processing circuits are on like 4 different pages. if some here can help me mark it up that'd be insanely helpful. also dont understand where the 0.1uf caps come in, also what voltage on the caps should i use? sorry im a noob when it comes to the theory but i have soldering skills and such to do it

Here's the service manual: https://www.mediafire.com/file/s8gaafpp ... 1.pdf/file
This looks similar to the set from the page before the current page on this thread.

Remove R3321, R3317, and R3319, those are the grounding resistors on the OSD circuit.

120 - 75 = 45, 43 ohms is a close standard value, so according to the mux diagram, you should use 43 ohm inline resistors and 75 ohm grounding resistors. Inject each color channel in the non-grounded path of the resistors you've removed.

For blanking, remove jumper JW436, and connect a SPDT switch as follows:

Pin 1: 5V supply with a 1K + 1K ohm voltage divider to bring it down to 2.5V.
Pin 2: R2733 after the Jungle chip.
Pin 3: JW436 pad leading to R3322.

I've never modded this chassis before, so I can't guarantee that this will work, but it's worth a shot to try it.
titan91
Posts: 57
Joined: Sun May 14, 2023 1:44 pm

Re: TV RGB mod thread

Post by titan91 »

Here's where I'm at with my Philips/Magnavox RF mono TV. Pressing 062596 followed by the status/exit button puts me into the Service Alignment Mode menu. Using the enter button instead puts me into the Service Default Mode display, which does not give me a menu. So anyone having issues getting into the service menu, try status/exit instead of enter after putting in the code.

I found what seems to be a service manual for another Philips model. It mentions:
Service Modes
Service Default Mode (SDM) and Service Alignment Mode (SAM) offer several features for the service technician,
while the Customer Service Mode (CSM) is used for communication between dealer and customer.
Note: Some L8 and M8 chassis sets use a software version that does not contain the Service Modes (see table). In
this case, use the special Factory Mode Remote Control. This can be ordered by service code 4835 310 57511.
Complete instructions are included. This remote control will place the TV in the Factory Mode and allow access to all
adjustments that a normal Service Mode contains (including setting Option Bytes). Error codes will not be available.
There is also the option of using ComPair, a hardware interface between a computer (see requirements) and the TV
chassis. It offers the ability of structured trouble shooting, error code reading and software version readout for all L8
and M8 chassis
https://vdocuments.net/19l800-7602-phil ... ml?page=19

Heres the SDM overlay:
Spoiler
Image
And here's the full SAM menu:
Spoiler
Image
I looked at the options and OP5 defaulted to 0. Probably because this set is RF only. I tried a few numbers mentioned last summer in this thread but none of them so far gave me CVI. The latest one I tried is 180 which gives me AV1 and FRONT. Both have a weird jailbar pattern. Don't think it's a test pattern since the pattern changes once the TV has warmed up after a couple minutes. These inputs on the IC aren't terminated so it's probably just capacitance from the floating pins.
Spoiler
Image
Whoever got the component CVI input to work for them, what value for OP5 did you use? For FRONT, does someone with a factory front A/V input get a photo of where that input board connects to the main chassis board? If I can do a composite or s-video mod with OP5 set to 180 I will go for that instead of component, if component isn't going to work. I can see if any of those inputs exist on the chip.
titan91
Posts: 57
Joined: Sun May 14, 2023 1:44 pm

Re: TV RGB mod thread

Post by titan91 »

I answered my own question. For anyone curious the Philips/Magnavox Option Bytes (OB) are for individual features. And the Option Bits (OP) are 8 boolean values that make up each byte. OB5 specifies what inputs are available when changing channels below channel 2. Per page 49 of the Philips 19PS40 service manual from 2004:
Option Byte 5 (OB5)
OP50: PIP
OP51: HOTEL_MODE
OP52: SVHS
OP53: CVI
OP54: AV3
OP55: AV2
OP56: AV1
OP57: NTSC_PLAYBACK
And here's the option Byte calculation table:
Spoiler
Image
OP52: SVHS 0 : SVHS source is not available, 1 : SVHS source is available, Default setting : 0. Note : This option bit is not applicable for EU.

OP53: CVI 0 : CVI source is not available, 1 : CVI source is available, Default setting : 0.
Thanks to PressLeft for all this great info:

https://shmups.system11.org/viewtopic.p ... 2#p1495922

Will mess around with this more now that I know what values do what. I noted that model PressLeft has is from 2004 since I assume the values for older sets will be the same for convention, technician education, and streamlined manufacturing's sake. My TV is from 2001.
titan91
Posts: 57
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Re: TV RGB mod thread

Post by titan91 »

Update. The only inputs I can get with the Philips/Magnavox MT2501 are AV1, AV2, and FRONT. They all have the same jailbar pattern. So the OP5 value I'll be using is 116. This tells it to turn on all 3 composite inputs and the S-VHS input. Now with consumer TVs in America, s-video never had its own option. It was often if not always assigned to video input #1. So it's possible AV1 is looking for both composite video on pin 40 and Y/C on pins 44 and 45 respectively. I'm going to try that and see what happens.

Assuming 75Ω termination and a low value DC blocking series capacitor like 1uf or 10uf is all I need for these lines.

Image
titan91
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Re: TV RGB mod thread

Post by titan91 »

Another update. I traced, terminated, and tapped CVBS1, 2, and 3. CVBS1 already has a DC isolation capacitor in series. CVBS2 and 3 did not so I added a 0.1uf ceramic one for those lines. 1 also had a 300Ω SMD resistor for its termination. Not sure why that would be there, so I removed it and used the normal 75Ω.

Leaving the back of the TV off and using crocodile leads was easy enough. I destroyed a couple of pads on the bottom of the chassis board though, they are very fragile. Was able to work around that. I also learned flux makes a great solvent to remove Sharpie ink. Lol...
Spoiler
Image
Image
Image
So, the actual results using OP5 set to 116, which enables CVBS 1-3 and S-VHS...

Injecting CVBS1:
Picture shows up on all RF channels and sound is static.
AV1: Black and no sound
AV2: Black and no sound
FRONT: Black and no sound

Injecting CVBS2:
RF channels are black with no sound
AV1: Black and no sound
AV2: Picture and no sound
FRONT: Black and no sound

Injecting CVBS3:
RF channels are black with no sound
AV1: Black and no sound
AV2: Picture and no sound
FRONT: Picture and no sound

So the first input overrides the RF input (video IF coming from the tuner). Sound still comes from the tuner's audio IF. That leaves 2 baseband audio inputs on pins 28 and 29. I also noticed after I did this mod the RF channels no longer show static at all even if there is no input signal to any of the newly enabled inputs. I'm guessing the chip detects the 75Ω termination. Which is fine with me.

Soon I'll try tapping C and injecting s-video into the FRONT input. I'm not sure if there was a model of this TV with s-video physically on the front. Curious to see if this does work, what input it shows up on. Maybe on models with s-video as a factory option Philips just used the CVBS3/Y and C pins on the chip.
retrogamer47658
Posts: 21
Joined: Sun Apr 23, 2023 5:16 pm

Re: TV RGB mod thread

Post by retrogamer47658 »

I traced, terminated, and tapped CVBS1, 2, and 3. CVBS1 already has a DC isolation capacitor in series. CVBS2 and 3 did not so I added a 0.1uf ceramic one for those lines. 1 also had a 300Ω SMD resistor for its termination. Not sure why that would be there, so I removed it and used the normal 75Ω.
Just to clarify, did this take away that "jailbar" pattern present? I'm dealing with a similar issue and would like to know if doing this would help my situation, which I'm guessing it would.
titan91
Posts: 57
Joined: Sun May 14, 2023 1:44 pm

Re: TV RGB mod thread

Post by titan91 »

retrogamer47658 wrote:
I traced, terminated, and tapped CVBS1, 2, and 3. CVBS1 already has a DC isolation capacitor in series. CVBS2 and 3 did not so I added a 0.1uf ceramic one for those lines. 1 also had a 300Ω SMD resistor for its termination. Not sure why that would be there, so I removed it and used the normal 75Ω.
Just to clarify, did this take away that "jailbar" pattern present? I'm dealing with a similar issue and would like to know if doing this would help my situation, which I'm guessing it would.
Oh, yes it did. Now those inputs are just black unless there's a signal connected. So I'm guessing the 75Ω termination tells the chip to disable the test pattern and enable the input. Because CVBS1 overrides the RF channels I disconnected it and re-used its termination resistor for the C (chroma) line. Once I did that, the jailbar pattern came back on AV1 and the RF channels. So, my guess to re-enable the RF input you would need to remove the termination on CVBS2 and CVBS3, or restore the original 300Ω termination to CVBS1.

On another note, some bad news with my set. Two problems: one, s-video isn't going to work. At least not with using the CVBS3 pin for Y and the C pin for C. The TV will display luma correctly, but when you connect chroma the image shifts a bit to the side (I think to the right) and you get color, but there are obvious dot crawl artifacts. So what the chip is essentially doing is combining Y and C internally then using the comb filter to separate them out again. And from my experience with RGB modding, the composite comb filter has a slight delay that shifts the image to the right. I'm guessing this is a firmware limitation. So although the data sheet specifically has CVBS3/Y and C next to each other, I'm going to try feeding luma in to CVBS2 next to see if that works. My logic here is no consumer TVs ever used s-video on more than the first two inputs (generally only on input #1). So maybe the chip will process it as s-video if I feed Y into CVBS2 or CVBS1. It's a long shot, but would be a big improvement over just composite.

The second issue I have is the TV will go into some sort of shutdown mode whenever I connect a PSOne or PS2. After it turns off it will turn back on, then shut off again. This continues until I disconnect the console. This one is a real bummer as I planned on watching DVDs and playing games on the PS2. This happens on CVBS2 and CVBS3. There is something with the sync signal it does not like. When I connect a color analog camera or an old Roku box, it works fine. Just the Sony consoles cause this problem.
retrogamer47658
Posts: 21
Joined: Sun Apr 23, 2023 5:16 pm

Re: TV RGB mod thread

Post by retrogamer47658 »

Alright, thanks! I'm working with a set that is also RF/mono only, I've gotten pretty far along with it except for the jailbar pattern when no source is plugged in and a sudden (temporary) brightness increase when using RGB.

Also, I've been looking over the datasheet for that IC you're talking about. You said something about a comb filter separating Y/C again, and I happened to come across this bit in the manual:

Image

Not entirely sure what all these values mean, but it seems like the comb filter can somehow be deactivated; that could, in theory, allow you to use s-video. If it helps, I enabled A/V on my set (Portland PT1301) by clipping one of the pins on the microcontroller; 5v on the pin activated the RF input and 0v activated A/V, so that was fairly simple to do. I will admit, there are a lot more service menu settings for this kind of stuff on your set than on my junky Portland, but the same concept could possibly apply in some way.

I have no idea what would cause other Sony products to not work with it though, sorry about that.
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