(Fixed.) KV25XBR, RGB, Audio, etc.

[DanAdamKOF]

edit: Basically all working. Couldn't figure out how to route audio through the 34 pin connector but that's OK.



Hi guys. I have a Sony KV25xBR. Currently I'm testing the RGB input by connecting some 20awg standed wire to the socket on a Genesis 2. I'm able to produce a horribly-colored image like this:

which looks to me like it's treating the signal as a digital RGB signal.
I tied the Mode Switch pin (21) to +5V and got the same picture.

My connector has the following connections made:
pins 34, 21 and 1 joined (audio select and Mode switch tied to +5V)
Pin 30 to Sync wire (Sync)
Pin 27 to Blue wire (Blue)
Pin 26 to Green wire (Green)
Pin 25 to Red wire (Red)
Pins 3, 7, 8, 9, 10, 13 joined to each other + Ground wire (audio R gnd, audio L gnd, Red gnd, Green gnd, Blue gnd, Sync gnd)

So to detail what I've tried, I tied 21 to +5V but that didn't make a difference in picture. I found an old writeup on interfacing an Atari ST to this monitor, where it said to join pin 29 (Blanking input) to +5V, that sounded wrong but I tried it anyway, and it didn't make a difference (I undid it right afterwards). Curiously, if I insert the Sync wire into Composite out, I get a very washed out full-color image. Playable but very ugly looking.
Here's a picture of it with composite as sync:

So the missing link is to take the monitor from thinking it's treating the signal as digital RGB and make it think it's analog... I'm looking at Google searches like crazy, but I'm not finding much about this.

Thanks for any help


edit: I've done some more poking around, I've tied 33 (RGB/Normal select) to +5V, no change. I tied 21 and 33 both to +5V, no change. I tried each separately and together tied to ground, no change.

 

[daskrabs]

I would try:

Pin 30 to Sync wire (Sync)
Pin 27 to Blue wire (Blue)
Pin 26 to Green wire (Green)
Pin 25 to Red wire (Red)
Pin 1 to +5V Genesis
Pin 11 to Genesis Ground

I think the the issue is you're overthinking it. Should be straight thru for most connections. The grounds you listed are way overboard. Leave the audio alone for testing.

 

[Yodd]

I googled a bit for this.

Have you looked at this document?
http://inwap.best.vwh.net/inwap/chez/kv25xbr.txt

Its about hooking the same TV up to an Amiga using composite sync. Same basic theory should apply if you are hooking up a Genesis or anything else.

 

[DanAdamKOF]

I have run across that Amiga txt. No audio hooked up right now. About to try daskrab's idea. FYI I'm using a disassembled floppy cable, just soldering to the pins that would normally crimp to the ribbon cable, very easy to mess with.

I saw that the Genesis 2 RGB cables use some caps and/or resistors, am I hooking this up right and me lacking those components is making my image screwed up?

Thanks btw

edit: lol. Hooking up +5V from the TV powers on the Genesis and produces a badly-colored image. Good thinking though.

 

[daskrabs]

http://members.optusnet.com.au/eviltim/gamescart/gamescart.htm

If my earlier suggestion doesn't work, add the caps and resistors shown. Might solve the issue.

 

[DanAdamKOF]

I don't have those components on-hand, I may just order some proper SCART cables since I'll need them eventually, this experimenting right now is meant to be rapid prototyping for my eventual nice 34 pin cable to SCART female socket.

I do have a PSX SCART cable I got long ago, I think I'm going to hook up my prototype to the SCART socket and see if that gives any hints. I know the PSX/2/3 uses Composite as Sync, so I'm not expecting perfection, far from it.

edit: I did ask about this over on NFG, if you guys can't figure this out hopefully someone there can.

 

[Yodd]

On the Genesis, in my experience, the caps aren't 100% necessary (but might be needed depending on your display). However the resistors are needed otherwise you get a very bright and washed out picture. I typically use either 75 or 100 ohm.

 

[DanAdamKOF]

OK wow, this is totally backwards to how I thought tonight would go:

PS2 via SCART RGB cable with composite as sync: works perfectly.
Genesis with almost-as-plain-as-it-gets RGB: bleh.

HEY HELLO PEOPLE GOOGLING ABOUT THE SONY KV-25XBR KV25XBR KV20XBR KV-20XBR RGB 15KHZ 15 KHZ SCART JAPANESE 21 JAMMA TV MONITOR 34 PIN PINOUT IDC CONSOLE PAL 240P 288P 480I 576I H V C SYNC HSYNC VSYNC CSYNC COMPOSITE VERTICAL HORIZONTAL CVBS RAW
(that oughta get a google robot's attention...)

Contrary to what you may have read online, like I had earlier, you CAN use Composite Video as Sync/CSync, on Pin 30 (H. Sync or Composite Sync). That dude on Shmups years ago is wrong or maybe he ran into an edge case that made him make an assumption.

I did not need to wire up any sort of select/switch/enable type things, I just wired up RGBS and GND (to SCART pin 17) to the corresponding SCART pins. Pressed the RGB button to light up the RGB light in front of the TV, and this worked. edit: Oh yeah, pin 34 is on the top left/ on the notch side, pin 1 is on the bottom right. If you forget or something shine a flashlight at the 34 pin jack.


To those of you in the future struggling with Sony 34 pin RGB like I did for so long (much longer than tonight), feel free to contact me or post in this thread. Let's end the confusion.

 

[DanAdamKOF]

OK new issue, I cant get audio to come through at all. SCART L/R go to L/R on the 34 pin connector... I linked both audio grounds on the 34pin to each other and to csync gnd, no change. Tried that with the audio select pin connected to 5V, no change (no change either when audio select is on its own). Taking a break for now. Shouldn't there be an audio ground on the SCART cable coming from the PS2? There isn't one.

Funny since I thought audio would be a lot simpler.

 

[DanAdamKOF]

Yeah so, I just wired some RCA jacks from the SCART plug to feed into a video input, and selecting that input has the audio come in with RGB. I wanted to avoid this since it uses up one composite input on the TV, but I guess it could be worse.

I am currently doing worse at games since I keep staring while playing...

 

[DanAdamKOF]

HI THREAD

I remade my adapter. This time I wanted audio to come in through the 34 pin connector and I got that working. The key to making this work is linking pin 34 to VCC (pins 1 or 2). Then feed L R and their GNDs to the appropriate pins.

Hmm looking above I apparently tried that before, no clue why it worked this time. All I can really say, I linked the GNDs on the SCART connector to each other, then connected GND to L and R GND from the 34 pin, and connected L and R to L and R input on the 34 pin. And pin 34 to VCC as I said.

 

[DanAdamKOF]

The Sony Profeel KX-2501a also uses this same connector. Searching this I ran across a few links with people interfacing to the 34 pin RGB port, possibly some of what's here might be of help:
http://www.theisozone.com/forum/viewtopic.php?f=145&t=60545
http://blog.andyselle.com/2015/06/17/a-rgb-display-for-an-apple-iigs

Also btw there's some NEC monitors (if I remember correctly) that have the same 34 pin connector, the pinout is the same (again, IIRC) so all of this should apply. If I knew the model I'd bomb this with more keywords Meanwhile: Sony Pro Feel

 

[DanAdamKOF]

To add to the above: Here's a thread on a NEC DM-2600P which has the same connector: http://forum.arcadecontrols.com/index.php?topic=102575.0
I don't think it's listed in this thread, but I know when helping someone out on the CRT Collective facebook group, I found the monitor somewhere for his NEC (dunno if it's this 2600P or another) and the pinout was the same as Sony's 34 pin RGB.

 

[faroffmods]

Hi DanAdamKOF

Just bumping this thread to get some activity going. I am looking to either build a 34pin cable from a floppy cable like yours. Or maybe modify an XRGB Framemeister female scart to male 8pin mini din cable to use with the PC-701 RGB adapter. The PC-701 was the RGB adapter made for the KV-25XBR, but it only was built to support Apple III and IBM personal PCs back in the early to mid 80's. I will likely go the PC-107 route first as modifying the XRGB cable should be as simple as moving a few wires around on the 8pin side.

In a perfect world, I would just shell out a good amount of money for a cable. (I'm looking at you SONY!!) But it seems no one sells them anywhere! Well, If you are looking to make some extra Christmas cash, let me know. I would gladly pay a good price.

 

[DanAdamKOF]

Nah unfortunately I don't have time to fab up a plug, I'm way too busy with IRL stuff until the new year. If I had time to offer my services I'd love to, I've had actually a fair amount of people ask me to make this for them for cash.

Just to reiterate in this thread what I said in the old thread, for the benefit of whichever lurker might be reading, I do plan to fully pin out the cable I made and provide some instructions so that anyone can follow my steps and have a well-working cable.

 

[nakedarthur]

Nah unfortunately I don't have time to fab up a plug, I'm way too busy with IRL stuff until the new year. If I had time to offer my services I'd love to, I've had actually a fair amount of people ask me to make this for them for cash.

Just to reiterate in this thread what I said in the old thread, for the benefit of whichever lurker might be reading, I do plan to fully pin out the cable I made and provide some instructions so that anyone can follow my steps and have a well-working cable.

Did you have a chance to test the RGB with more systems? I've heard of some Genesis cables not including all the necessary caps, so I wonder if that could be why it wasn't working.

 

[DanAdamKOF]

My KV-25XBR still isn't set up but I'm planning to start moving stuff around and set it up kinda soon. I used it with PS2, PSX, SNES, a few PCBs, but I don't remember if I hooked up a Genesis at some point.

 

[nakedarthur]

My KV-25XBR still isn't set up but I'm planning to start moving stuff around and set it up kinda soon. I used it with PS2, PSX, SNES, a few PCBs, but I don't remember if I hooked up a Genesis at some point.

Nice! Thanks for info. Is the pinout above in first post what you used?

 

[DanAdamKOF]

I don't have it in front of me right now to compare. The first several posts were troubleshooting while I couldn't at first get the RGB input running properly, so possibly not. There's a pinout in the back of the manual. Hmm, apparently I never linked to it earlier on, it's on this page: https://esupport.sony.com/perl/model-find.pl?mdl=KV-25XBR

 

[nakedarthur]

I don't have it in front of me right now to compare. The first several posts were troubleshooting while I couldn't at first get the RGB input running properly, so possibly not. There's a pinout in the back of the manual. Hmm, apparently I never linked to it earlier on, it's on this page: https://esupport.sony.com/perl/model-find.pl?mdl=KV-25XBR

Ah, thanks! Makes sense now.

 

[nakedarthur]

I don't have it in front of me right now to compare. The first several posts were troubleshooting while I couldn't at first get the RGB input running properly, so possibly not. There's a pinout in the back of the manual. Hmm, apparently I never linked to it earlier on, it's on this page: https://esupport.sony.com/perl/model-find.pl?mdl=KV-25XBR

OK, I threw this together real quick last night based off what you said above. The port at the top is looking at the back of the TV, and it's numbered in reverse of the cable as you specified. The red writing is the cable pins, starting with 1 as the red stripe and counting down. Please let me know if anything looks wrong.

My plan is to use a 12" 34-pin floppy connector, cut off one side, then solder directly to female SCART head.

-image redacted to prevent future confusion!-

 

[DanAdamKOF]

This should be correct, I based it on the cable I made and currently use:


I didn't verify every single pin, just used my multimeter a bit to find my bearings then hopped between the pinouts and made notes as I went along by eye. This is probably correct though.

On the SCART side, I joined all the GNDs together.

Pin 34 is Audio Select and when it's tied to 5V it lets you feed audio through the 34 pin connector. I used a short piece of wire that links pins 1 and 34.

For my cable I busted off the back of a 34 pin connector and soldered to the pins I needed, I tried at first to use the cable coming off of it but the wires are super thin and felt like they wouldn't hold up to wear and tear. One other thing I did was loop some wire through these holes on the end so I can remove it from the KV-25XBR more easily, you can see it hanging off the back of the 34 pin.

I'd recommend using a female SCART connector meant to sit on a cable, I used a PCB mount one which I attached to perfboard for sturdiness, it was a pain in the ass because it doesn't match standard pin spacing so I had to keep bending the legs and test fitting it until it all sat in there, very annoying.

Some pics of my cable:

 

[nakedarthur]

Crap, got permission errors when trying to view any of the files you added. Is it because my account is new? Thanks for the heads up on the floppy wires being super thin, didn't consider that.

 

[DanAdamKOF]

Didn't know about that, seems like a lousy restriction really. I uploaded them to imgur, here they are:

 

[nakedarthur]

Awesome thanks! Waiting for a few parts to come in and I'll start messing with it. Strange though, our numbers for the flat side seem to be different. Green matches up, but Blue and Red are reversed and Sync seems to be completely different. I'll have to take another look at it.