Main > Monitor/Video Forum
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 :laugh2: 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 :laugh2:)... 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.
--- Quote ---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!!!
--- End quote ---
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... :laugh2: :laugh2: :laugh2: 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.