2nd or 3rd attempt to a rgb tv mod. Any advice wellcome.

[abispac]

So my niece gave me a 19 ich tv its a curtis matches tronics model cm19022s, i could not locate a service manual, it has two chips, a toshiba ta1282n and a zilog 5007 or szm-370th1, i couldnt find information on the zilog chip , but the toshiba i got the pdf datasheet and a gif image
https://datasheetspdf.com/pdf-file/492994/Toshiba/TA1268N/1

Now according to the datasheet and the image, 14 its my blank signal, 15,16,17 are rgb, so it should be a straight mode right? I always get confused if i should get my rgb cables on the rgb in or the rgb out, i believe its in the in, so ill just satudy a bit more again and hopefully i dont screw this up again, lol  God knows i have fun doing this. But since this tv its a 19inch i actually would like to keep it.
Anyway its late saturday, i have to do some research before i get my hands dirty, but any advice would be wellcome (besides mikeA telling me to slow the ---fudgesicle--- down  )... thanks for reading and have a great day.

[abispac]

So someone at the shmups forum allready tried this but failed a bit, and i think its because he soldered everything within the same chip, so instead ima go the 8bit guy rgb mod way. As i do have a port available for the grounds and the 5v for the blanking. I just need a little help. I traced my rgbs to this yellows, what i think are resistors, can anyone confirm those at c211,c209, and c210 are resistors? thanks for the help. They are at the bottom.


Added the shmups sopic i found for information.

So pins 14-17 look like what we want. I desoldered these pins and pulled them out of the board.
I wired my input, vga from a SNES via gscartsw 3.4 into one end of a 4pdt switch, along with 3.3v from pin 18. I wired the original OSD signals from the bottom of the board to the other side of the switch. Video ground was wired to pin 13. The output went from the 4pdt switch to the pins 14-17. The signals going to 15-17 (RGB) each had a 75 ohm resistor to ground, followed by a 0.1 uF ceramic capacitor in line. The sync was wired to the underside of the board into the composite video input.

I turned on the TV, turned on the SNES, and voila! perfect image, no adjustments needed. I decided I was going to take out the 4pdt switch as it would be dedicated for a cab. I discharged the tube and unplugged the anode cap. The next day I plugged the anode cap back in and went to show it to someone and the colors were off, like one was missing or something. I thought maybe one of the lines had disconnected and that it would be fixed when I reconnected everything.

Fast forward, the tube is now in the arcade cabinet. I wired pin 18 straight to pin 14, then wired a female SCART head (with 3 resistors to ground and a 0.1uF cap in line for each of the RGB lines in the head) to the inputs 15-18 and 13 for ground, sync wired to the composite input. I connected my SNES via SCART into this, turned on the TV, then turned on the SNES. Mario World has all of the correct colors, but every white is missing.

How do I fix this? I would move on and try to find another TV to try it on, but I had it working briefly and it looked so good, so I really would like to get this working.

The female SCART cable is very short, about 4 inches, and the capacitors are wired directly to the pins 15-18. The resistors are still in the SCART head.

I tried wiring sync to pin 43 on the jungle (Y in) but now the picture has no sync. I can see through the garble that red green and blue are still there, but white is still missing. Any advice would be appreciated. I'm going to keep an eye out for any other 19" and try again if this doesn't work out.

Thanks to all, please help!!!

[abispac]

I just realise i have the same chassis as the 8bit guy, the same, it might be a little bit more modern but its the same ---smurfing--- one, so all i got to do to succeed its just straight copy his mod, so ill post results tomorrow, fingers crossed.

[abispac]

So im at halfway succes, i did the mod, exactly as the 8bit guy did, i also had no smoke coming up after getting everything together again, ill just need to test it with groovymame, but ill have to wait as my wife is using the computer... Mi mode does not look profesiona at the moment, but is enough to test it out. Ill post more pictures later on, so once again, fingers crossed.

[jennifer]

I can't read your schematic, But if you are dealing with a jungle chip you can lick your fingernail (after sanitizing it of course so you don't get corona) and touch your wet nail to the pins until you get interference from you RGB outputs, Tap a wire good to go.

[abispac]

So i can say im almost done with this mode, i just cant figureout what im missing. I did everything exactly as the 8bit guy did, well, not the fancy conector, as i might add it later on.  Hook my pc with my vga brekout cable, and bam, clear colors but bad sync

So i started emudrivers on my other tv (i had both monitors hooked, i always do that on crtdrivers) and dont matter what settings i choose, 15khz, 31khz o 60 khz, i cant get this thing to sync. i can still see that colors are gonna be good, i ust need a bit of help in here please.  So so far, as the 8bit guy did, the rgb cables have the 75ohm resistors terminated to ground, all grounds go to ground, i get the 5v volts from the same place, and the sync i try to get it from the yellow rca entrance on the back of the tv. but no luck. Do i need to add a 75ohn resistor on the sync cable as well? or do i need to build the vga cable has he did on his second video?  thanks for any help.
This is how far i got.


and a link to the second video where he builds the vga cable.

[buttersoft]

You're saying this same video source, a PC or whatever it is, will show an image on your arcade monitor, but not on this TV, correct?

Are you getting composite sync directly from VGA pin 13 by turning on the option to in VMM/crt_emudriver? (You say you're trying to "get" sync from the yellow RCA socket on the TV, but i assume you're feeding sync into that.) If there are no components in the pin-13 composite sync line at present, try adding some - do not add a resistor to ground just yet. Putting a 1K pot in line and dialing it up from 0R is probably a place to start.

[abispac]

You're saying this same video source, a PC or whatever it is, will show an image on your arcade monitor, but not on this TV, correct?

Yes sir, all arcade monitors the image shows good quality and just fine.

Are you getting composite sync directly from VGA pin 13 by turning on the option to in VMM/crt_emudriver? (You say you're trying to "get" sync from the yellow RCA socket on the TV, but i assume you're feeding sync into that.) If there are no components in the pin-13 composite sync line at present, try adding some - do not add a resistor to ground just yet. Putting a 1K pot in line and dialing it up from 0R is probably a place to start.

To be honest on arcade monitors i just put both sync cables together, 13 and 14, thats it, works just fine.and yes you are right, im trying to feed sync via the yellow rca socket and that dont work.  i did try to turn on the sync option in vmm but i didnt read the part that i had to redo the modlines, so ill try again, but my card its a hd7000 and that option apears to be for hd5000 and lower. Anyway if i add a 1k pot, how would i go about doing that?  Now i didnt saw the 8bit guy doing anything extra to get his tv in sync, unless im missing a detail.
The pots i have have tree legs, so i really apreciate if you elight me on how to do that part, thanks mr Buttersoft.
Oh and i forgot, using 15khz generic mode, should be ok right? I did try 31khz, mode, 15khz dual sync, 25khz, and some others, non seem to work for me.

PS: This is a picutre of the computer on a regular arcade monitor with a weiya chassis.

 

[buttersoft]

VGA sync outputs at TTL levels = 5Vp-p. Try composite sync from VMM first. If that doesn't work, go back to separate H- and V-sync, then using a 480i mode that works on your arcade monitors, start with a 500R resistor and a 1k pot in each line, then merge and feed into the CRT where composite video would normally go in. Dial the pots around and see what happens.

[abispac]

  i should be ashamed of myself. Im not sure how the arcade monitors displayed and image, because my vga cable was a total mess. I notice it, because, the sync did not have an effect on the tv, it was like if i had nothing hooked up, there was no difference if i had the sync cable connected or disconnected, i took my multi-meter and started checking the pins, man what a mess, the sync cables where at the grounds and i was using one ground as v sync and a cable thats not even used as a h sync, so i redid my cable and will test it out again tomorrow. im pretty sure everything its gonna work out of the box this time.   
Thanks to this tv now im gonna have a good working cable and i learn to double check that before i screw more monitors...
Ill post results later on.

[abispac]

VGA sync outputs at TTL levels = 5Vp-p. Try composite sync from VMM first. If that doesn't work, go back to separate H- and V-sync, then using a 480i mode that works on your arcade monitors, start with a 500R resistor and a 1k pot in each line, then merge and feed into the CRT where composite video would normally go in. Dial the pots around and see what happens.

Thanks for the advice mr Buttersoft, im pretty sure with the correct pinout on my cable it will work rigth out of the box as the 8bit guy did too. Now i do have a question. Using vmm with Ntsc 60khz option, i almost had a stable image, using 15khz the image was a mess, do you think the 8bit guys was using ntsc60khz instead of 15khz? do you think 15khz should work? thanks for the help.

[abispac]

just re-did my cable with correct pinouts, and colors are washed out, i get a semi stabilized image,using the composit option in vmm makes no diference, will keep tying.

[abispac]

VGA sync outputs at TTL levels = 5Vp-p. Try composite sync from VMM first. If that doesn't work, go back to separate H- and V-sync, then using a 480i mode that works on your arcade monitors, start with a 500R resistor and a 1k pot in each line, then merge and feed into the CRT where composite video would normally go in. Dial the pots around and see what happens.

just finished buildind the cables,hope this is it

[buttersoft]

NTSC would be 60Hz -NOT- 60kHz. Hz will be FPS. 15kHz is the scanrate. Section e) of the guide i wrote contains more info - https://www.aussiearcade.com/forum/arcade/m-a-m-e-emulation-projects-and-discussion/89704-a-guide-to-connecting-your-windows-pc-to-an-sd-crt-tv-pvm-or-arcade-monitor

NTSC60Hz would be a tautology, because NTSC is 60Hz. It may be referring to a preset in VMM like PAL, or Generic15? I'd start with NTSC at 480i and get that working first.

You do appear to have 3 wires coming from each 1k pot. But you only need 2, and one of them must go to the wiper in each case, otherwise dialing the knob will do nothing and you have a fixed 1k resistor. No harm having the third line, just don't connect it. Merge the right two output lines, and feed them into the composite video input. fire up your source, then dial the Horizontal sync line in, then the vertical.

EDIT Do not connect ground to anything here. Ground from the source can go straight to the set (i.e. the outer ring of the RCA jack, but not connected to anything in the sync circuit) And please keep all relevant info in one thread.

H-sync ---------500R-----------1k pot----------(nothing)
                                               |
                                               |
                                               ----------------- (to composite video in)
                                               |
                                               |
V-sync ---------500R-----------1k pot -----------(nothing)

[abispac]

So the cable is a success with a regular arcade monitor and the weiya chassis, i know both 1k pots are working properly as they do scramble the picture if i play with them. However, nothing happens when i use them on the tv. Seem that im not getting sync from the yellow rca neither from the rf coaxial outlet. I need to figure out how to get sync from this. Heres a pic of my jungle chip

thanks for any advice

[buttersoft]

I see above that you are switching to the AV channel, so it's probably not that. If the composite video port on the TV works by itself, with a normal composite video source, then sync is going in there. I'm not sure why it's not working from your PC, but is on a regular arcade monitor. You are plugging the sync into the center of the port, not the outside ring which is ground?

Have you checked your modelines to see if sync is set to negative or positive? Arcade OSD might be able to show you that. You want both set to negative for this, i think.

[abispac]

I see above that you are switching to the AV channel, so it's probably not that. If the composite video port on the TV works by itself, with a normal composite video source, then sync is going in there. I'm not sure why it's not working from your PC, but is on a regular arcade monitor. You are plugging the sync into the center of the port, not the outside ring which is ground?

Have you checked your modelines to see if sync is set to negative or positive? Arcade OSD might be able to show you that. You want both set to negative for this, i think.

so the yellow rca wasn't working,I desoldered it and soldered cables directly and the Xbox worked, however it has 3 point, one for video one for ground and one for let in know the osd that video has been connected. However in not sure where to bridge this so the "connect video" message disappear, should I connect this to ground or to video?

[buttersoft]

Following the traces on the board and metering stuff is the best way to tell. After that, try each, one at a time?

If the xbox worked, wire up the PC sync the same way, shouldn't need more than that.

[abispac]

after closed inspection, my main ground was broken ,so i re-soldered, the video was ok and the detection signal was broken to, so i followed the traces and i soldered the cables at the next point, and i got good signal,ill test the pc next.

[abispac]

so i test it out after soldering everything right, and i got a successful rgb tv mod, thanks mr buttersoft,i couldn't do it without you.

[nexusmtz]

Congrats on your persistence and success. 

[buttersoft]

I need to have a lie down

[abispac]

Congrats on your persistence and success. 

thanks, i had to show mikeA i could do it...

2 more monitors on death row.

here you go mikeA ,this one for you. now i got 3 working monitors,soon to be 4. 

[Mike A]

I am glad to see you succeed.

You stuck with it this time instead of chucking them onto the discard pile.

[abispac]

I am glad to see you succeed.

You stuck with it this time instead of chucking them onto the discard pile.

trust,the sony tv was to big and to heavy for a project anyway, not worth the fix,and i still got those 2 broken weiya chassises but since they are cheap here,ill use them for parts.