Hi everyone, I want to add a S video output to a VCR. I do understand that people in here might have knowledge about adding and doing a mod of a S video output.
I have a Sony SLV-ED1PS VCR. and here is the diagram for it Where I highlighted in Yellow and blue I think I found V - and not sure for C output as I don’t know if that means it’s C - chrominance? S Video needs only 3 connections
Is V - and 2. Is C - and 3. Is GND. I need help here? Also with any composite video port these 3 wires are already in every device all ready. The only difference with composite and S video is that the V- and the C- are mixed together in composite Video vs S Video they are separated to get rid of interference and makes the picture quality a bit better.
Yes, that is correct. I’m only looking for Y output and C output only. As I want to separated Y and C signals from mixing with each other as that is how composite video works.
It’s not clear to me that Y (luminance) is available as an output. The schematic is a bit blurry and I can’t see what all the pins off of the chip say. But it seems entirely possible that composite is being created internally within the chip rather than in an analog mix of Y and C.
However, you could probably find a way to decode the composite signal into Y and C. This might not offer any improvement to the video quality over composite, but if the goal is simply to produce the S-video format, this could be an option.
Thanks for your reply. Here is a better picture of the video chip. “Pin 50 says C out” I’m guessing that could be chrominance? Also I highlighted in purple where ‘Pin 50 that is name C out’ makes a connection to “Pin 55 name CIN” and maybe brings the chrominance signal into the video chip and come out in “Pin 57 as video out” as that is what it is name it also it probably looks like this luminance V- and C - and goes straight to RCA output. But what do you think going off what I said here and what the diagram showing? and also for a another picture
I draw a green line showing if I was for example to disconnect Pin 55 from video chip and send that possible C- chrominance signal to the future S video output maybe that would work?
Typically “video out” means composite out. This is not what you want. This is not luminance.
However, with the better image I see that pin 68 is Y out. This is luminance.
I would try connecting the C out (pin 11) and the Y out (pin 68) to an S-video connection and see what happens. I’d also test these signals on a scope beforehand to make sure they look like proper Y and C signals.
Thank you for your response. I actually think you’re onto something. Here is a picture of me highlighting the pin 68 that is V- it looks like it goes into something. I circled it in the orange circle. Would you happen to know what’s it going into? and coming out and going back into the video pin 63?
Also for C out same thing pin 11 C out goes into something? and comes out and goes back into pin 13 into the video chip?
The Y and C are both going into an 8-pin IC. This IC also takes a clock signal and a select signal. Tracing the select signal we see that it goes to a PAL/NTSC selection output. So this IC is very likely to manage PAL vs. NTSC.
Your S-video output should occur after this IC so your output will be valid for whichever output format the VCR is set up to do.
Since the post-selection signals are going back into the main video chip and utilized there in some way, you might need to buffer the signals to split them off to your S-video output.
If you’re lucky, the PAL/NTSC IC will provide enough buffer for the split. But if you wind up seeing a dark image, it would probably be due to a lack of proper buffering at the point of your split.
Going off what your saying about post-selection signals are going back into the main video chip and utilized there in some way.
I drew a picture highlighting with arrows do you think maybe this is how that video chip is sending out the C- and V-?
For example on the left side the pin 11 C-is going out to 8-pin IC.and come out to pin 13 and goes into the video chip and brings the c- out to pin 50 and makes a connection to pin 55 and then goes into pin 57? and comes out to the RCA output.
To have a better understanding of where it’s going and doing here’s a picture NT 3.58 = NTSC and on my VCR there is a switch button to switch from 4.43 to 3.58 NTSC for playing back on PAL TV. So it’s probably grabbing that C- signal and some how filtering it out when switching from the different resolution switch button on the back of the VCR and it’s right next to the RCA VIDEO output.
