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

[vol.2]

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

I think making the shell mounted one work is going to be a lot easier. That mod had an awful lot of thought and time put into it, and they also just lucked the hell out with the placement. You might also get that lucky with whatever random TV you're working on, but I don't think it's wise to count on it.

[BazookaBen]

I should have taken pics of the one I did for a kv-13fm14 recently.

I found an old s-video connector contained in a A/V adapter for an old GPU.

It was encased in epoxy, and I just drilled a hole through an empty section of the epoxy (to avoid wires) and ran a 12AWG solid copper wire through. Then I bent in a U-shape to where it went into a couple large blank vias on the motherboard, then soldered it in. SUPER strong that way, I wish there were a way to find them in bulk in a form like that.

[MaliciousBingus]

After reading this thread herehttps://electronics.stackexchange.com/q ... chassis-tv I am far less confident about adding inputs to this hot chassis tv. I suppose the only way would be to use the tv exclusively with an external isolation transformer, far enough from the tube to not cause distortion. If anyone has any ideas, definitely let me know though. It’s a shame, I really like this tv.

[vol.2]

After reading this thread herehttps://electronics.stackexchange.com/q ... chassis-tv I am far less confident about adding inputs to this hot chassis tv. I suppose the only way would be to use the tv exclusively with an external isolation transformer, far enough from the tube to not cause distortion. If anyone has any ideas, definitely let me know though. It’s a shame, I really like this tv.

I haven't ever done it before, but I've considered running one of my hot chassis sets with an internally mounted isolation transformer. One that can handle a TV is somewhere around $45. Not sure how that would be an issue, but maybe you're finding something that I don't know about.

If you are somehow concerned about magnetic interference from the transformer, you could shield it.

I am not aware of any specific issues with using an isolation transformer for a line device, I know there are plenty of electronics that do this, but I guess I'd still ask around if you have doubts. A different forum that is more specifically geared towards electronic repair is a better place to confirm your design's safety.

[MaliciousBingus]

Yeah, installing the transformer in my set wasn’t hard and it powered up fine, but the transformer has to be pretty close to the tube in my case to fit it, and I saw notable rippling in the picture that would lessen as I increased the distance between the two. I need to look into the mechanics of shielding I suppose.

[vol.2]

Yeah, installing the transformer in my set wasn’t hard and it powered up fine, but the transformer has to be pretty close to the tube in my case to fit it, and I saw notable rippling in the picture that would lessen as I increased the distance between the two. I need to look into the mechanics of shielding I suppose.

There are 3 levels of shielding you can employ.

1) steel can from a can of beans or something. in most cases this is more than enough to block anything, but it can be tricky to make it fit, and you'll have to carefully insulate it to prevent shorting which can be tricky with a can

2) 1mm thick copper shielding. Following Lenz's law this should mitigate stronger interference and has the advantage of being softer and easier to bend. Being flatter material it will be easier to insulate

3) the strongest material you would ever need is Mu Metal. It's more expensive, and may be difficult to acquire outside of older sets that use it

[MaliciousBingus]

Yeah, installing the transformer in my set wasn’t hard and it powered up fine, but the transformer has to be pretty close to the tube in my case to fit it, and I saw notable rippling in the picture that would lessen as I increased the distance between the two. I need to look into the mechanics of shielding I suppose.

There are 3 levels of shielding you can employ.

1) steel can from a can of beans or something. in most cases this is more than enough to block anything, but it can be tricky to make it fit, and you'll have to carefully insulate it to prevent shorting which can be tricky with a can

2) 1mm thick copper shielding. Following Lenz's law this should mitigate stronger interference and has the advantage of being softer and easier to bend. Being flatter material it will be easier to insulate

3) the strongest material you would ever need is Mu Metal. It's more expensive, and may be difficult to acquire outside of older sets that use it

Thank you for your assistance, I’m very appreciative. My transformer is the Triad N-67A, which has a shield lead that the data sheet says is part of the secondary/output side, but doesn’t really offer much else. In my installation I just heat shrunk and tied it off since my TV didn’t have an earth connection. Do you know if this has anything to do with magnetically shielding my transformer?

[vol.2]

Thank you for your assistance, I’m very appreciative. My transformer is the Triad N-67A, which has a shield lead that the data sheet says is part of the secondary/output side, but doesn’t really offer much else. In my installation I just heat shrunk and tied it off since my TV didn’t have an earth connection. Do you know if this has anything to do with magnetically shielding my transformer?

That's for if you want to ground the shielding. Forcing the shielding to ground potential increases it's ability to cancel out magnetic interference. It's the same concept as using ground planes in a PCB to isolate impedance sensitive traces. If I was doing it, I wouldn't mess around with that. I think just plain metal shielding would be sufficient

In the case of the transformer you are using, that terminal is intended to connect to the third prong (earth) of a standard North American 3 pronged power plug. I'm not entirely sure what the consequences of doing that would be in this case because, in North America, the neutral line is connected to the earth line at the breaker box, so it effectively un-isolates the neutral line. You need to ask safety questions on a more electronics oriented forum as I'm definitely not qualified to give safety advice.

One thing I can tell you for sure is that you cannot hook an oscilloscope ground up to a device that has not been plugged into a fully isolated transformer because (since the earth is connected to the neutral in the box) it will create a ground loop back to the neutral on the power grid outside your house, effectively pulling ground up to 120V potential. It should just trip the breaker, but it could also blow some crap up in the process.

How that works with using video inputs I can't tell you.

I'm also not going to go on the record saying that just using a regular IST inside the set is totally safe. That's on you as well. I will probably try to do more HW about it before I try with my set. I have successfully got it RGB modded, but I pulled it all out until I can satisfy myself it's okay to just use the IST (and also feel like spending money on it). But I have been collecting sets for 30 years and I got others to play with.

[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.

So The PS2 has colour but the C64 doesnt

https://www.dropbox.com/scl/fi/84klanb3 ... 7bng9&dl=0

The C64 Is made in Hong Kong

https://www.dropbox.com/scl/fi/naps9v3q ... 3k5o2&dl=0

[kakaboy70]

Ok I think my problem is the replacement video chip I recently installed must be NTSC.

Mt breadbin is fine. Thanks for all your help KPackRatt2k

[vol.2]

Ok I think my problem is the replacement video chip I recently installed must be NTSC.

Mt breadbin is fine. Thanks for all your help KPackRatt2k

You should be able to figure that out from the part number on the VIC II chip.

[nmur]

I don't know how I didn't notice this before - I mustn't have had the TV turned on for very long during the modding/testing stages, but I'm finding that the s-video video signal display fades away to nothing after a couple of minutes. I can still hear audio, as well as the 15kHz whine, and the neck still glows, but no video signal displays, other than the OSD. I've tried different input sources as well. What's also weird is that if I turn off the TV and the source and turn them on again, the video still isn't visible. However if I leave it all turned off for a while, and come back later to try, it will work again for a short while before fading to black again. I didn't observe any obvious overheating of anything inside the TV.

Has anyone witnessed this behaviour with their mod before?

Revisiting this mod after about 2 years.

I now thankfully have video working well, which is great. However I'm actually having trouble injecting my audio - I can't seem to get it working through many different attempts of connecting up to the "AF IN" pin of the IF block. I've also tried replicating the audio circuit in jeffez's reference mod, with two 4.7uF caps, but cannot hear anything coming out of the speaker.

If I connect audio directly to the "AF OUT" pin, I hear audio loud and clear, but without the ability to adjust the volume of course.

This is what my circuit looks like:

Red cross is a cut trace, green dot is where I was planning on injecting audio, and red dotted line is just showing that it's essentially connected like this (chassis has unpopulated audio switching circuitry which is replaced by a jumper in my set). My actual IF block is a IFB-389SS, with a CX20015A inside.

For reference this is the simple audio circuit in jeffez's mod that I also tried recreating:


Does the IF block need to be in a certain state to process audio or something? Like a pin that needs a certain voltage? I can't seem to find much data on the IFB-389SS block or the CX20015A inside.
Or could I have fried something while playing around?