Sony Trinitron S-Video/Composite Mod (RF-Only TV) SOLVED

[Ryeno]

I did a SCART and S-Video mod on a Sony BA-1 Chassis. Both mods are easy to do but the S-video mod disables RF and Composite. I wanted those inputs to still work so I searched for a solution and, I found it, the TS5V330 video switch. The switch is self-explanatory except each, used and unused, source pin and each unused drain pin must have a resistor to ground or else the switch will not function correctly. The drains need 10 ohm resistors and the sources need 50 ohm resistors. The gist is that Y/C and CVBS (from the AV SW) will be fed into the THS7316 before the TS5V330. This is because the jungle chip on this unit expects a 2vpp signal and because the THS7316 allows us to connect the grounding resistors for the TS5V330. If you don't need the 6db gain then you could use 150/75R to drop the voltage back to 1vpp. Below is a partial write-up.

BA-1 chassis, based on the KV-20TS32, move R474 to R423 and move R475 to R424, to separate luma from chroma.

THS7316
Pull Y/C or S-video from IC402-1 or R480 and IC403-1 or R479 and connect them to the THS7316 RGB Amp pins 1 and 2.
Install a 0.1uF C0G capacitor into C438 and connect the negative end to THS7316-3.
All 3 inputs into the RGB amp should be AC coupled.
Only the Y/C outputs are AC coupled. CVBS output is DC decoupled. AC coupling did not work on the CVBS output.
0.1uF bypass capacitor.

TS5V330
Pin 3 and 6 are connected together.
* You might be able to DC couple all 3 inputs.
** I used 150 ohm resistors but 75 might work.

pin 1 - IN SW, pin 6 of MICON or R329 (10K) if MICON Pins 8 and 9 are rebuilt and s-video switch is jumped
Pin 2 - THS7316-8 through 220uF cap* & 150 ohm to ground**
Pin 3 - THS7316-6 through 75 ohm resistor & 75 ohm to ground
Pin 4 - IC402-7
Pin 5 - THS7314-7 C through 0.1uF>=* cap & 150 ohm to ground**
Pin 6 - Pin 3
Pin 7 - IC403-7
Pin 8 - 0.1uF cap to pin 16
Pins 9 & 12 - 10 ohm to ground
Pins 10, 11 , 13, & 14 - 50 ohm to ground
Pin 15 - EN SW, ground
Pin 16 - 5v

pics

[jeffez]

Nice work. I used a generic analogue switcher CD4053B. Two of them gave me six channels which was enough to handle s-video and audio switching.

[BazookaBen]

So how does this switch know to switch? It autodetects the live signal?

[vol.2]

So how does this switch know to switch? It autodetects the live signal?

"The CD405xB analog multiplexers and demultiplexers
are digitally-controlled analog switches having low ON
impedance and very low OFF leakage current. These
multiplexer circuits dissipate extremely low quiescent
power over the full VDD – VSS and VDD – VEE supply voltage ranges, independent of the logic state of the
control signals"

"Wide range of digital and analog signal levels:
– Digital: 3 V to 20 V
– Analog: ≤ 20 VP-P
• Low ON resistance, 125 Ω (typical) over 15 VP-P
signal input range for VDD – VEE = 18 V
• High OFF resistance, channel leakage of
±100 pA (typical) at VDD – VEE = 18 V
• Logic-level conversion for digital addressing
signals of 3 V to 20 V (VDD – VSS = 3 V to 20
V) to switch analog signals to 20 VP-P (VDD – VEE
= 20 V) matched switch characteristics, rON = 5 Ω
(typical) for VDD – VEE = 15 V very low quiescent
power dissipation under all digital-control input and
supply conditions, 0.2 µW (typical) at
VDD – VSS = VDD – VEE = 10 V
• Binary address decoding on chip
• 5 V, 10 V, and 15 V parametric ratings"

[BazookaBen]

So what does that mean you think? I'm still not sure how it's choosing the active input.

Was also curious how Ryeno's particular switch works

[vol.2]

It needs to see some voltage at pins 9,10,11 to switch on.

Spoiler

I don't know how he has it wired up, but all you need is to do is tweak the difference between Vdd and Vee to tune the voltage range for turn-on.

Spoiler

[Acilles]

I thought i might give an update. Here is my latest diagram minus the composite input. As BazookaBen pointed out, having composite the way i had it would affect the svideo signal. To use composite you would just need to use an external adapter.



Also i have revised my switching PCB. I was able to simplify the circuit by adding another CD4053B. The last one had some issue with it so i decided to just start again. Just waiting on fabrication. Hopefully it works this time and i can show how it fits in the above diagram.

hai jeffez. Can I request a copy of the gerber pcb file?

[jeffez]

hai jeffez. Can I request a copy of the gerber pcb file?

I'll have to dig it up. It was a while ago when I did this and I recall there was a small mistake on it which required running a wire from one pad to the ground plane. It's also not exactly well documented other than what you see in this thread.

[Vaporwave64]

Hello, I'm new to the Schmups forum, I hope this is the right place to reply. I have a Sony kv-20tr23, it has a BA-1 Chasis just like the one that was modded and share here in the thread. I would like to figure out how to get S-video from my set, I don't mind losing Composite/RF input. What's the easiest way to go about this?

[jeffez]

Hello, I'm new to the Schmups forum, I hope this is the right place to reply. I have a Sony kv-20tr23, it has a BA-1 Chasis just like the one that was modded and share here in the thread. I would like to figure out how to get S-video from my set, I don't mind losing Composite/RF input. What's the easiest way to go about this?

It looks like your set is RGB mod-able. I would just go with that.
https://sector.sunthar.com/guides/crt-r ... -ba-1.html

[jeffez]

For anyone that is interested, here is the gerber files for the PCB I made if they want to make it them selves. It takes the stock internal TV signals (TV_IN) and the new svideo and audio inputs you add on the back of the set (AV_IN) and outputs one or the other (TV_OUT) based on a HIGH/LOW input line on the PCB (labelled 'O' in TV_IN) . It's intended for RF only sets with Y/C jungle inputs but may have other applications.

NOTE - Use at your own risk as I am no expert and can't give any kind of guarantee I have got it running on my set with mono sound. The board supports stereo sound but I haven't actually tested that feature. There is also a mistake I made which requires connecting one of three pins to ground which I will mention below.

https://drive.google.com/file/d/1eiGlup ... sp=sharing

One of these 3 pins needs to be connected to ground.



Here is the parts list



INSTALATION
The idea is you are cutting the stock signals from the TV and redirecting them to this PCB (TV_IN) then connecting the TV_OUT pins into (essentially) where you cut the stocks signals from. The AV_IN pins are where your new input signals go. You can combine Y and C if you just want to run composite but it's probably better to use an external adapter for composite just so you can retain svideo (with it's better picture quality) as an option.

TV_IN (Stock video and audio signals from tv. In my case the Y, C and Audio from RF)
GND - Ground (From TV)
S - Sync from TV/Stock signal (Any signal that contains Sync such as composite or luma, may require some trial and error)
Y - Luma
C - Chroma
M - Mono audio (use either this or stereo (L R) inputs
R - Audio right channel
L - Audio left channel
O - HIGH/LOW signal. LOW will make TV_IN out put on TV_OUT. HIGH will out put AV_IN on TV_OUT. You can use a switch or in my case I used the HIGH/LOW signal from somewhere in the TVs mainboard that switches between 0v and 9v when pressing 'VIDEO' on the tv remote.
V - Voltage from the TV (in my case the 9v feed tapped off the TVs main board)

AV_IN (svideo and audio inputs you add to the back of the TV)
GND - Ground from inputs (connect audio and svideo ground together too)
Y - Luma
C - Chroma
R - Audio right channel
L - Audio left channel
NOTE L and R audio be mixed to mono and output on TV_OUT M (mono) pin if needed

TV_OUT (Video signals to connect to the jungle chip as well as audio output for TV's audio circuit or and external audio output/speaker)
GND - Ground (From TV)
S - Sync input connection spot on TV circuit or jungle pin.
Y - Luma in on jungle
C - Chroma in on jungle
M - Mono audio output connection spot
R - Audio right channel output connection spot
L - Audio left channel output connection spot

NOTE again use at your own risk. I am no professional and this is really just a prototype I made just for my project. Another member on here asked for the gerber files so I decided to document my work in case someone else may want to use this.

For reference (as shared before) here is what the board looks like



And here is how it was installed on my mod

[vol.2]

For anyone that is interested, here is the gerber files for the PCB I made if they want to make it them selves.

Thanks jeffez for the awesome contribution. I'm sure that a lot of people will find it helpful

[jeffez]

For anyone that is interested, here is the gerber files for the PCB I made if they want to make it them selves.

Thanks jeffez for the awesome contribution. I'm sure that a lot of people will find it helpful

Thanks. I can't believe it was in back in 2019 when I started on this and I made that PCB back in mid 2021, finally finishing the project around mid 2022. Life's changed allot since then but I still try to jump on here from time to time.

[kakaboy70]

I also have the KV1414AS and will give this mod a go, thanks for your work.

[kakaboy70]

So I did this mod without the board and I got a picture but its in Black and White, I only just picked up this TV so not certain if it has colour but I did try my coleco in RF before I started the mod and even thou it has a dicky power switch I did see colour in the garbelled graphics. Is there something I can check or is the tellie no good?

[KPackratt2k]

So I did this mod without the board and I got a picture but its in Black and White, I only just picked up this TV so not certain if it has colour but I did try my coleco in RF before I started the mod and even thou it has a dicky power switch I did see colour in the garbelled graphics. Is there something I can check or is the tellie no good?

Make sure your Chroma wire isn't touching sensitive components such as the flyback or the power supply. When I modded a TV/VCR combo for S-Video input, I was getting a black and white image on Composite unless I routed its Chroma wire a certain way. It also helps to double check your work to make sure Chroma is wired correctly (for example: If you had to solder a wire to a transistor, check to make sure you've soldered it on the right leg. Some transistors have a center collector pinout rather than center base, so there's a possibility you've mistakenly soldered to the wrong leg).

If you're using electrolytic capacitors for coupling the inputs, make sure the polarity is correct. The negative end should face the input jack while the positive end faces the jungle chip.

Also check to make sure your input device is feeding the correct format signal. Since you're in Australia, you should be using a device that outputs a PAL signal.

[kakaboy70]

Thanks for the feedback very appreciated. Im using Green Caps 100nF as I cant source 0.1uF I dont think these are polarised but may also not be the right ones. My wiring is running under the board to the rear where the RF is but I will double check all my solder joints etc.

[KPackratt2k]

Thanks for the feedback very appreciated. Im using Green Caps 100nF as I cant source 0.1uF I dont think these are polarised but may also not be the right ones. My wiring is running under the board to the rear where the RF is but I will double check all my solder joints etc.

100nF = 0.1uF, which means the capacitors are the correct value, therefore they shouldn't be the problem. I would also test the 75 ohm termination resistor on Chroma to make sure it's not directly shorted.

[kakaboy70]

So are you saying Luma will create the picture and chroma is for colour? Sorry for sounding like a noob

[KPackratt2k]

So are you saying Luma will create the picture and chroma is for colour? Sorry for sounding like a noob

Correct. Luma is the black and white image, while Chroma is the color component that's applied to the image.

[kakaboy70]

Ok so I connected the crt to my C64 which is what I been testing on minus the chroma connection and its the same. I'm waiting on a new power supply for my PS2 that has a Svideo adapter just to try another input and see what happens.

[MaliciousBingus]

Sorry to dredge up this old thread. I have a KV-2020R (p-3b chassis) with a CXA1013 Jungle IC. Based on what I’ve seen in this thread, I should be able to pipe in S-Video. What I’m unclear about is doing these mods on a live chassis, and if there’s any issue there? Do I just need to run my grounds to the RF tuner area, since it’s isolated from the rest of the board? Or do I need to incorporate an isolation transformer before the main power supply to make this mod feasible/safe? I see a lot of fear-mongering about live chassis TVs, but saw no real mention of any issues in this thread. Thanks!

[KPackratt2k]

I'm assuming your set only has an RF input? In this case there's no isolated power supply section available to connect your ground to since that's only implemented on the models with AV inputs. The RF input ground is "floating" as it's not connected anywhere on the chassis, so connecting your input ground to that wouldn't work.

Depending on how the electricity is wired on your house, using a hot chassis TV modified for AV inputs could pose a shock hazard in the event that the outlet it's plugged into is wired backwards since the only available ground point on the chassis is referenced to the Neutral blade, so you'll have to use an isolation transformer to prevent that in this case. There are isolation transformers that you can install internally in the TV's cabinet, but depending on the size of the board compared to the spacing in the cabinet there might not be enough room inside to go that route.

If you have a schematic for a model with AV inputs, you could theoretically rebuild the isolated power supply section and use optocouplers between the input jacks and the jungle chip, but this can be difficult and will most likely rely on obsolete components that are difficult to source short of sacrificing them from a broken set.

[MaliciousBingus]

I'm assuming your set only has an RF input? In this case there's no isolated power supply section available to connect your ground to since that's only implemented on the models with AV inputs. The RF input ground is "floating" as it's not connected anywhere on the chassis, so connecting your input ground to that wouldn't work.

Depending on how the electricity is wired on your house, using a hot chassis TV modified for AV inputs could pose a shock hazard in the event that the outlet it's plugged into is wired backwards since the only available ground point on the chassis is referenced to the Neutral blade, so you'll have to use an isolation transformer to prevent that in this case. There are isolation transformers that you can install internally in the TV's cabinet, but depending on the size of the board compared to the spacing in the cabinet there might not be enough room inside to go that route.

If you have a schematic for a model with AV inputs, you could theoretically rebuild the isolated power supply section and use optocouplers between the input jacks and the jungle chip, but this can be difficult and will most likely rely on obsolete components that are difficult to source short of sacrificing them from a broken set.

Thanks for the quick and detailed response. You’re correct that the tv is RF only. I have looked at other p3-b sets with composite inputs and yeah, it definitely looks like a chore to rebuild that design. Truthfully I’ve already bought a transformer to install in my set, but as you guessed, it’s quite big/heavy, and will have to hang off the top of the back. I fashioned a mounting plate out of a cheap black abs sheet I found on Amazon, to spread the load away from the 4 screw mount points and take some pressure off the 40-year old plastic case. It’s still a bit unnerving though. Maybe I’ll get a socket tester and see if my place is wired properly, and decide if it’s worth going the iso transformer route.

[MaliciousBingus]

I'm assuming your set only has an RF input? In this case there's no isolated power supply section available to connect your ground to since that's only implemented on the models with AV inputs. The RF input ground is "floating" as it's not connected anywhere on the chassis, so connecting your input ground to that wouldn't work.

Depending on how the electricity is wired on your house, using a hot chassis TV modified for AV inputs could pose a shock hazard in the event that the outlet it's plugged into is wired backwards since the only available ground point on the chassis is referenced to the Neutral blade, so you'll have to use an isolation transformer to prevent that in this case. There are isolation transformers that you can install internally in the TV's cabinet, but depending on the size of the board compared to the spacing in the cabinet there might not be enough room inside to go that route.

If you have a schematic for a model with AV inputs, you could theoretically rebuild the isolated power supply section and use optocouplers between the input jacks and the jungle chip, but this can be difficult and will most likely rely on obsolete components that are difficult to source short of sacrificing them from a broken set.

Thanks for the quick and detailed response. You’re correct that the tv is RF only. I have looked at other p3-b sets with composite inputs and yeah, it definitely looks like a chore to rebuild that design. Truthfully I’ve already bought a transformer to install in my set, but as you guessed, it’s quite big/heavy, and will have to hang off the top of the back. I fashioned a mounting plate out of a cheap black abs sheet I found on Amazon, to spread the load away from the 4 screw mount points and take some pressure off the 40-year old plastic case. It’s still a bit unnerving though. Maybe I’ll get a socket tester and see if my place is wired properly, and decide if it’s worth going the iso transformer route.

So as an update - I installed the transformer and unfortunately I think it generates too much magnetic flux to have near the tube. I assume the ones typically used in CRT designs are step-down style, where as mine was 115V in, 115V out at 1.3A. I checked my outlets and they’re all properly wired, so I think I’ll proceed without isolation.

[BazookaBen]

Does anybody here have a solid recommendation for a specific s-video connector from digikey, mouser, etc.?

The ones I've bought so far don't have the notch at the top that allow Playstation s-video connectors to plug in, so I've had to modify all of them. And some are board mounted and others are panel mounted and I'm not sure what I prefer there, or what's best for the end user in regards to removing the back shell for cleaning/maintenance in the future

[vol.2]

Does anybody here have a solid recommendation for a specific s-video connector from digikey, mouser, etc.?

The ones I've bought so far don't have the notch at the top that allow Playstation s-video connectors to plug in, so I've had to modify all of them. And some are board mounted and others are panel mounted and I'm not sure what I prefer there, or what's best for the end user in regards to removing the back shell for cleaning/maintenance in the future

Nope. I scoured all of those places and found nothing good.

The best ones I've found are the Console 5 ones. I think they probably get them from Ali Express in bulk or something.

[BazookaBen]

Nope. I scoured all of those places and found nothing good.

The best ones I've found are the Console 5 ones. I think they probably get them from Ali Express in bulk or something.

You have to run a lot of extra wire for these, right? So it has enough slack that removing the back shell doesn't rip the wire out? And I assume you have a JST connector or something like that in between the board and s-video connector?

I basically would love to find something that can be mounted to the board, even if upside down like you do with the 10-pin DIN for Turbonanza mod on TG16 consoles.

[vol.2]

You have to run a lot of extra wire for these, right? So it has enough slack that removing the back shell doesn't rip the wire out? And I assume you have a JST connector or something like that in between the board and s-video connector?

If you run a connector, you don't need a lot of extra wire, but obviously enough to open the back of the shell and disconnect it.

I basically would love to find something that can be mounted to the board, even if upside down like you do with the 10-pin DIN for Turbonanza mod on TG16 consoles.

I'm not sure what the Tubonanza mod ends up looking like, but how would you mount it to the board if there aren't through holes in the board for it to affix to a spot directly in front of your hole?

I guess you could hot glue it in place or something? Idk, that wouldn't work out for most TVs because they have components and stuff in front of where you might mount it.

But there do also exist small PCBs that you can use to breakout the rear solder lugs on an Svideo connector, and you could probably make use of one of those in some way. I think the NESRGB kit I got from Tim W had a couple in there or something.

[BazookaBen]

I'm not sure what the Tubonanza mod ends up looking like, but how would you mount it to the board if there aren't through holes in the board for it to affix to a spot directly in front of your hole?

https://github.com/zaxour/TurboNanza

Pics in the link but you solder an adapter board to some available vias for ground and in some cases, scrape away solder mask and solder to the ground plane