Sega Genesis Doesn't show up video

[darkshadow1804]

well guys, i did manage to get a HIGH DEFINITION GRAPHICS genesis very cheap in a store (for about 4 USD)...and HOLY CRAP! the video quality difference between model 1 and 2 is astonishing...well
the thing is that today i wanted to experiment with it, making a RGB cable...i did manage to make it, but then i realize that newer monitors doesn't accept 15khz RGB signal...so my LCD tells NO SIGNAL...then i re-solder all back again...now the LCD says ENERGY SAVING...and then shuts off...
i said...f*** up...so i un-did everything...and left it as this was never happened...but i got a surprise...
the console doesn't wanna to show up any image at all (IF it shows up, it's for about 10 seconds and SOOOO blurry and with noise)...the sound is just fine and clear (i love its sound, so crystal clear)...
so i'm desperate, i don't know what to do...it's my first priority genesis...my model 2 sounds like an a** compared to model 1...please help D:

[alec006]

Have you tried to RF to ensure that the console is producing some kind of picture? Sounds like when you soldered everything back you created a short somewhere. The short may be something touching the 5 VDC Pin/Signal which causes the console to reset or show no video at all. It also may be touching the ground pin/signal thus weaking the signal. Try to use a little solder as you can when your resoldering the A/V out port. Hopefully if you get it fixed, I ,as well as some other people here, can help you get a crystal clear picture on your flat screen tv or LCD.

[darkshadow1804]

thx for the reply! well, i think there WAS/STILL IS a short in somewhere...i double, triple checked the contacts and there is nothing touching each other (tested with a multi-tester with the conductivity beep option)...i think i blew up one or two capacitors near the video chip (VDP)...because the RF signal brings up clear audio but only noise as image =S

[alec006]

Ew,hopefully the VDP is intact,it should be thou that's what capasitors,resisitors and a bunch of other things on the board are for to ensure they blow and the chip remains unharmed. I would replace the capasitors to see if that fixes the problem. Too bad you can't check the RGB signal, then again if you have a 32x you could. But I would get composite and RF working again before even trying to see what RGB is producing.

[raylydiard]

Try replaceing the 7805 regs.

[darkshadow1804]

man, it was so hard to unscrew the heatsink screws x_x
well, the regs (both) are giving 8.1v at one side, and 5.1 at the other, dunno if it's normal since the genesis model 2 that i have gives 9v(8.89v) and 5v
i'll search for something blown now o.O
any ideas? ^^

[alec006]

I found a scematic for the MegaDrive model 1, but the website seems to be down for some damn reason,hopefully it comes back up and tells some voltage info.

http://emudocs.org/Genesis/mega1.png

[darkshadow1804]

wow, thanks...but one problem, the RGB to CV doesn't appear in the pic .___.
btw, i just posted a vid on my youtube channel: http://www.youtube.com/watch?v=d0CF0-zFo_E showing some experiment i made and i can get b/w image or less colors but with a flickering image
hope that could give you a better clue of what's going on D:

EDIT: about an hour ago i...really didn't know what i did, but for about 5 minutes or less...the image was in b/w and about 30 seconds later was in color (just a few colors) but with a stable image...
i suspected on a capacitor, so i removed...after that NO image could be displayed...so i tried with another capacitors i had (dif. capacities) and almost all "worked" (giving a b/w stable image) surprisingly (except for a 0.47uF one lol) being 220uF the original .__.U
so i soldered it, change cartridge to be sure that THAT is the solution, and no, that WASN'T, the problem is still there...so i soldered back the previous capacitor that was in there...so i suspect that could be a capacitor problem (one must have gone blown, but i can't figure it out which one because all of them are in good shape)
so i'm still waiting for more clues =O

[raylydiard]

dude you have the same tv as me lol
ok i replace all caps on all my segas systems.
but not allways need replaceing.
one thing have you tryed rf mate.
or you could do svideo mods
or use a scart to hdmi and prob solved.

[darkshadow1804]

it's a flatron m197wa lol
well rf does give a very good mono sound and noisy video...
i tried making an s-video cable (with capacitors on each Y and C side) and IT WORKS!!!
the only thing is that in SPECIFIC CERTAIN scenes the video flickers (data select in sonic 3 / sonic 3 & knuckles) but that's nothing...i can actually play
thanks mate!

one thing now, i didn't make a RGB -> SCART cable because here in south america our tvs and appliances don't have that input/output...could i make a component cable out of the RGB+CompositeSync signal? (ONLY IF it's possible, i'll try it on my model 2 sega genesis now, i wanna leave my model 1 as is now ^^U)

[alec006]

Well that's a relief,I can't believe that damn scematic didn't show the multi out port. Ask for a SCART cable, you can get those for next to nothing buy use a SCART to Component convertor box to achieve the best possible signal in YUV which is still RGB. Of course there are people that went the analogue SCART to digital HDMI route which is alright, but it upscales it to 720p, hence why I like analogue component box better. But in the end the TV will upscale it somehow anyway,thou I like when the TV upscales vs when the box upscales it. Whatever is simpler and easier for you both look wonderful.

[raylydiard]

i know that the usa tvs dont have scart what do the usa tv use as a rgb out put?
and how about japan tvs? aswell.

[raylydiard]

One more thing use 75ohm on the Y-OUT and CHROMA-OUT
for both MB3514 and CXA1145P.
if you have other encoders please let me know and i will track down the pin out.
i will try this on a genesis model one. soon and genesis model two.

[darkshadow1804]

wow, you read my mind mate XD
i was about to telling you about that lol
well, chile uses the NTSC standard (most of them, despite newer ones, including mine...are multinorm), so we use usa tvs, these have all connectors but scart...i mean...s-video, composite, component, rf, hdmi, rgb (equivalent to the vga, i use it with my dreamcast with the vga cable), dvi (to the pc too) (my monitor/tv has all these)
rgb in here is the pc connection (monitor) and doesn't like the 15khz and composite sync from the genesis...i need to get horizontal and vertical separatedly...but despite that, newer monitors doesn't support the 15khz

in this video i show how the image looks now (it has some noise and the flickering i told ya):
http://www.youtube.com/watch?v=byrQf23_irk
well, you guessed right, my genesis 1 uses the CXA1145P (my genesis 2 uses a samsung, which i think is crappy XD)...the resistors should be BEFORE...i mean...in between the capacitors and the chip? or could it be AFTER, in between the TV and the capacitors?

thx for your help =)

[raylydiard]

Could you give me the samsung number thats on that chip please.
plus try it with out the n between the capacitors and the chip
try this one thing directly solder 75 ohm on the Y-OUT and CHROMA-OUT of the sony chip
and should fix it dont use capacitors and see it should be fine i have the same prob one most of all my model one useing rgb. jumping on the screen silly.
i hope i can help you out.

[darkshadow1804]

wow thanks!
i'll try to solder the resistors in between capacitors and the chip, if it's still jumping, i'll try without the capacitors and i'll tell ya =)
ummm the samsung chip in my genesis 2 is the ka2195d =D

[raylydiard]

http://members.optusnet.com.au/evilt...rt/Ka2195d.pdf
ok with this one you could try to do one thing r =red b=blue g= green
like the hd ones on your tvs and just use that as a video out put if it works i think we are lucky here in the uk we use the MB3514 all model 2.

[darkshadow1804]

wow, thanks mate!
i'll try everything when i get a bunch of 75ohm resistors ^^U
well, you say, get those outputs, but into what cables? component? where do i put the sync signal? with the green? lol
the PAL genesis (megadrives) 2 uses the MB3514 chip, because is a PAL RGB converter chip...it's known for bringing the superior quality over any other RGB chip o.o
american genesis 2 have the samsung one because is only NTSC RGB converter...unlike the genesis 1 ones, that output onto one norm or another if a certain pin is grounded or with voltage XD