Mega Drive color problem, white being yellow!

[klinkowski]

Hi.
I'm having a problem with the colors on my Sega Mega Drive model HAA-2510, the white is yellow.
Like, really yellow.
Images to see what I'm trying to say

https://flic.kr/p/q8Gfvz
https://flic.kr/p/q6xeJA

I've searched this problem and I never encountered the same problem anywhere.
What could it be?
It was tested in two CRT television and one LCD, all the games works fine, the sound is awesome, but this yellow over the white thing is really anoying.

[ComradeOj]

HAA-2510. That's an early Japanese model 1, right?

Maybe it's time to replace all of the capacitors, or at very least, the ones clustered around the video encoder. It's not too hard of a job if you've soldered before. I'm not sure exactly what capacitors you will need though. The caps will all be labelled with their voltage and capacitance, you could just make a list and buy those.

[klinkowski]

HAA-2510. That's an early Japanese model 1, right?

Maybe it's time to replace all of the capacitors, or at very least, the ones clustered around the video encoder. It's not too hard of a job if you've soldered before. I'm not sure exactly what capacitors you will need though. The caps will all be labelled with their voltage and capacitance, you could just make a list and buy those.

What are the "bad things" that can happen if I do something wrong?

[aha2940]

What are the "bad things" that can happen if I do something wrong?

Your system might stop working completely. However, replacing those capacitors is not that hard *if* you have done some soldering work before. It takes time, though.

Regards.

[bustedstr8]

What video connection are you using?

[ComradeOj]

What are the "bad things" that can happen if I do something wrong?

Worst case, you make a mistake and your console will be permanently unusable. But it's not that hard of a job if you've soldered before. It's not super easy to make fatal mistakes when re-capping, but you should still be careful and take your time. I'm not guaranteeing that replacing the capacitors will fix your issue, but it's the most likely cause for weirdly colored video output.


Here's a short tutorial for replacing caps on youtube:
It doesn't go to detailed into how to solder them, but I think it will still be helpful.

[Ace]

That doesn't look like a capacitor problem but rather an RGB mixing issue inside the console. Normally, whites showing up yellow would be a color mixing issue where the blue is too weak. It's possible one of the SMD components on the blue input to the video encoder needs a reflow. I had that issue with a PAL MegaDrive Model 1 (VA6) except this one had completely missing reds, resulting in whites showing up teal. What board revision is in this MegaDrive? If it's one I own, I can retrace the color inputs to the video encoder for you.

[Bibin]

I do not think this is an analogue mixing problem. That would result in reduced blues. I think the problem might lie in his VDP, in the DAC for the blue channel. Look at Sonic's spines - what should be dark is actually lighter, and areas of darker grays aren't tinted yellow/green. I believe the MSB of the blue color is simply missing, and his blue channel is effectively the two low bits.

Here's a side by side of his picture and a proper Sonic 2 title screen:



See the harsh changes in the shading of the blue area.

A re-soldering of pins or capacitor replacement will not fix this sort of problem as it is internal to the VDP (the MD does not expose the pixel data digitally typically).

[klinkowski]

Well
Back from the dead...
Sorry for the really late response.

I didn't have time to fix this issue, so I gave the Mega Drive to a retro store that repairs consoles
They are giving back the console to me, but the problem persists.
They couldn't find the problem.
I will find another one to play the games that I own, but I really want this Mega Drive working properly because it is important to me, family related, childhood memories...
I will keep on replying everyone who tries to help here, now I have more time.

I do not think this is an analogue mixing problem. That would result in reduced blues. I think the problem might lie in his VDP, in the DAC for the blue channel. Look at Sonic's spines - what should be dark is actually lighter, and areas of darker grays aren't tinted yellow/green. I believe the MSB of the blue color is simply missing, and his blue channel is effectively the two low bits.

Here's a side by side of his picture and a proper Sonic 2 title screen:



See the harsh changes in the shading of the blue area.

A re-soldering of pins or capacitor replacement will not fix this sort of problem as it is internal to the VDP (the MD does not expose the pixel data digitally typically).

Is there a way to fix if this is the case?

[l_oliveira]

There's nothing wrong with his Mega Drive VDP, that I tell you.

There's NTSC and NTSC-J. NTSC-J has a different spec with different signaling voltages at the CVBS line. I remember back then I had problems using a Japanese MD with my Brazilian TV in RF. The whites were too strong. I would solve it putting a 1K resistor from the CVBS signal to GND.

From Wikipedia:

"It is based on 'regular' NTSC, but is slightly different. The black level and blanking level of the NTSC-J signal are identical (at 0 IRE), as they are in PAL, another video standard, while in American NTSC, black level is slightly higher (7.5 IRE) than blanking level. Because of the way this appears in the waveform, the higher black level is also called pedestal. Since the difference is quite small, a slight change of the brightness setting is all that is required to enjoy the "other" variant of NTSC on any set as it is supposed to be.

The over-the-air RF frequencies in use in Japan do not match those of the US NTSC standard; there are also international differences in the frequency allocations for other services such as FM radio. The encoding of the stereo subcarrier also differs between NTSC-M/MTS and the Japanese broadcast standards."

If such a fix is applied twice it would cause weird effects to the video, like that yellow hue the OP has. I'd suggest the OP open the console and check if there's any mods on the video encoder area.

[klinkowski]

There's nothing wrong with his Mega Drive VDP, that I tell you.

There's NTSC and NTSC-J. NTSC-J has a different spec with different signaling voltages at the CVBS line. I remember back then I had problems using a Japanese MD with my Brazilian TV in RF. The whites were too strong. I would solve it putting a 1K resistor from the CVBS signal to GND.

From Wikipedia:

"It is based on 'regular' NTSC, but is slightly different. The black level and blanking level of the NTSC-J signal are identical (at 0 IRE), as they are in PAL, another video standard, while in American NTSC, black level is slightly higher (7.5 IRE) than blanking level. Because of the way this appears in the waveform, the higher black level is also called pedestal. Since the difference is quite small, a slight change of the brightness setting is all that is required to enjoy the "other" variant of NTSC on any set as it is supposed to be.

The over-the-air RF frequencies in use in Japan do not match those of the US NTSC standard; there are also international differences in the frequency allocations for other services such as FM radio. The encoding of the stereo subcarrier also differs between NTSC-M/MTS and the Japanese broadcast standards."

If such a fix is applied twice it would cause weird effects to the video, like that yellow hue the OP has. I'd suggest the OP open the console and check if there's any mods on the video encoder area.

I am not familiar with the mega drive board and the mods, I will post a picture of the console as soon as I get it back. 7 hours or so

[l_oliveira]

I am not familiar with the mega drive board and the mods, I will post a picture of the console as soon as I get it back. 7 hours or so

That will help out me with helping you, for sure.

[klinkowski]

Ok then.
My Mega Drive is black and white now
http://imgur.com/4O2HT9Y

The board:
http://imgur.com/lYTODQw

Tell me what you want to see of the board and I will take a pic

[Segaedge]

I tell you what you problem is. First, may I ask which country at you located at, or where did you get this MD from?
Your MD has been modded/transcoded to a different region, the Master clock Oscillator on your board is a TXC 53.634155Mhz, what is that PAL-N, PAL-M or PAL-D guys?
The original Oscillator for a NTSC MD is rated at 53.693175Mhz, which in turn divides the clock signal for the video encoder.

[klinkowski]

I tell you what you problem is. First, may I ask which country at you located at, or where did you get this MD from?
Your MD has been modded/transcoded to a different region, the Master clock Oscillator on your board is a TXC 53.634155Mhz, what is that PAL-N, PAL-M or PAL-D guys?
The original Oscillator for a NTSC MD is rated at 53.6931Mhz, which in turn divides the clock signal for the video encoder.

I live in brazil. My TV supports NTSC, PAL-M and PAL-N
This Mega Drive is in my family since I was a kid, it was imported from japan.
I think it has or had a transcode to PAL-M (transcode, is that it? Idk)
I'm trying to disassebly furter to see the back of the board, but one screw is making me crazy here.

Also, a little correction to your post.
It is TXC 53.634165Mhz