Searching for a Genesis RGB Bypass Board. 9-25-17

[infidelity]

I have been looking for several months now, for the Genesis RGB bypass board. I've tried Voultar, db, and various other sites that used to have them in stock. Is there anyone that might have a spare one for a Model 1 that they are willing to sell? Or know of an actual online retailer that has them in stock? Thanks for reading!

[AndehX]

DB is supposed to be getting some in this month for testing, but there's been no update on his website yet, not sure whats going on. His triple bypass board looks like the dogs bollocks though. I'll be one of the first to order one when he puts them up for sale.

[zeruel85]

Hello,

if you want I have only one available.

This is my personal revision of ArcadeTV's RGB Bypass for Sega Mega Drive (also compatible with Sega Master System).
It has a THS7374 with selectable LPF and a sync buffer to provide 75 Ohm CSYNC video level (thanks to Markus for the idea).

Sales thread:
viewtopic.php?f=4&t=60272

[infidelity]

Hey there, I just clicked the link you posted, and it says 0x on the Mega Amp? Is this accurate? Thanks!

[zeruel85]

Hey there, I just clicked the link you posted, and it says 0x on the Mega Amp? Is this accurate? Thanks!

Mega amp is an audio mod, you are searching for a video one, don't you?

It's also written 1x RGBMD.

[infidelity]

Oh my bad, yes the video one.

[zeruel85]

Oh my bad, yes the video one.

No problem.

[Syntax]

Can vouch for zeruel85's RGB board.

Recently installed one and was very impressed with the PCB quality, and the end result was perfect.

Thanks again.

[zeruel85]

Can vouch for zeruel85's RGB board.

Recently installed one and was very impressed with the PCB quality, and the end result was perfect.

Thanks again.

Thanks to you (thus I don't know who you are honestly, lol).

Did you purchase something on eBay, I suppose?

[Syntax]

Purchased an Snes RGB amp and Mega Drive RGB amp.

Ended up completely removing the original video encoder just to make the install neater.
Had no noticeable problems leaving it connected playing on a CRT.

The board size and layout was very well thought out.

[infidelity]

Excellent! Looking forward to installing it once it arrives! I just need installation pics for a VA2, cause his install pics show a VA1 Japanese model. I just haven't gotten around to ripping my system open again, so I can give him pics of the bottom of my MoBo. Would anyone have a photo of the bottom of a VA2 Model 1 Genesis?

Zeruel85, would these installation instructions work for your board, on my VA2? http://www.retrorgb.com/genesis1rgbbypass.html

[infidelity]

I installed zeruel85's board into my VA2 Model 1 Genesis, but I get no video output when I power the machine on. The sound, and controller functions work however. (Used Sonic 2 cartridge as a test) I'd like to post my pics of my installation, please check the following link.

https://m.imgur.com/a/PYgey

zeruel85 was suggesting that there may be capacitors/resistors on my rgb euro scart cable, and suggested I remove them. Is there anyone here that could upload a photo, of exactly how this should look, before and after the cable fix? I only have 2 cables for my Genesis & 32x, and I don't want to ruin them in he process. Being told how to do something for me is a little tough, without some sort of visual aid. Thanks to anyone that can help out. Thank you!

[ApolloBoy]

Is your SCART cable wired for composite video as sync or does it use composite sync? If it's using composite video that would explain why you don't have an image.

[Syntax]

Why you decided to lift the cpu pins and solder to them instead of just soldering to the CXA legs or lifting them and soldering to the pads is beyond me.

There is no benefit other than MAYBE avoiding running blue next to the subcarrier traces.

You would of been better off lifting the subcarrier pin.
Composite video is encoded from RGB in the CXA chip.

Also if your using comp video for sync you WILL get a picture but it will have no sync. Don't listen to that other guy

Remember that the csync line runs from the cpu to the AV port AND the CXA, you need to cut the trace near the av port if you want to wire the new csync to it.

With my setup because I no longer had comp video as I had removed my cxa completely I ran csync to the comp video pin on the AV header and just use normal scart leads.

Having capacitors inline in your scart plug will not effect the picture to a noticeable point. Capacitors in series just have lower capacitance, not an issue. Having said that I'm sure you need them in the scart as there are none on the amp.

Looking over your install its hard to pick but at a guess you have wired buffered csync to the csync pin on the AV header BUT the original csync is still on that line, so your mixing TTL csync and buffered csync, not good. But should still show a scrambled picture....

The only reasons no picture would show
All RGB lines are wired to incorrect pins
There is no power to the amp
There is no power to the TV sets blanking

[infidelity]

I was following a guide on retrorgb, where they had pulled the pins up for r,g,b,csync. That's why I did that.

I don't anything else about your suggestions, regarding my csync. If you could please give me a diagram as to what needs to be cut, that would be great.

My euroscart cable uses csync. Zeruel85 suggested soldering a wire on the csync of the start cable, to a specific spot to create a bridge, but I still do not get video. I've been using rgb before I attempted this mod. I have no bridges on my Genesis.

I was wondering too if the board was not receiving the proper 5v. I followed his document and soldered a simple wire to one of the CXA pins for the 5v. Should I solder the 5v to another location? And are there certain CXA pins that I cut, that need to be restored?

Thanks!

P.S. these are the installation diagrams I was given.

https://drive.google.com/drive/mobile/f ... VdyNFB5djg

The only difference is in cut pin 11 on my CXA, I didn't cut 10.

Again, all I care about is R&B. All other forms of video output I will never use. So if I could please be told what pins should be cut and restored on my CXA, and where to solder the GND & 5V from the rgb amp board, that'd be great!

[zeruel85]

Do you have a multimeter?
Check the 5V first of all.
Then all other signals.

[infidelity]

No I do not own a multimeter. But this is not my first soldering job, if modified several consoles. But I'm curious on the 5v... Should I have this soldered elsewhere for proper 5v's?

[Syntax]

Shouldn't really be modding blindly without a multimeter. Thinner wires would be nicer too.

I see you've tried both vcc inputs on the cxa, the melted insulation..
You could solder directly to the main 5v transistor.

From your pictures is say it's powered fine though.

[infidelity]

The vcc pin you mention, was me accidently cutting the wrong leg last year, so I bridged it.

Idk where the 5v transistor is, is there a photo of it, and the spot on it to solder to?

I'm not here to get into a discussion on why I don't have a multimeter or other stuff, I don't do this for a living, it's a hobby, I've never ran into an issue like this with a console mod till now, I really don't want to revert everything back, I want this board to work, so I'm thinking it might be the 5v, and I'd like to rule that out, so if anyone has a pic/diagram of the 5v transistor, and where to solder to it, that would be a great help!

[Syntax]

Should buy a $10 multimeter. You won't regret it.
It would make your "hobby" much easier.
Like you wouldn't need to move wires around worrying about a 5v feed. You'd just check it.

Don't worry about power, should be fine from the cxa vcc. Same with ground. Unless something has popped

[infidelity]

I'd really like to try another spot for the 5v, could you direct me to a photo of it on the Genesis, and where to solder?

[infidelity]

Is the 5v transistor the piece that is screwed into the heatsink?

[zeruel85]

It should be pin 2 of IC15.
But, again, it would help if you have the chance to check the voltage.

[infidelity]

I will purchase a multimeter tonight at walmart. I don't know how to use one, or if the Genesis needs to be on or off.

[infidelity]

Can anyone tell me exactly how to use the multimeter to check my connections, please? I'll be purchasing it tonight. I looked up videos but they are all so different...

[infidelity]

Got my multimeter.
https://imgur.com/a/ht55C

But I'm still in the dark with what settings, and how to do this??

[zeruel85]

Select 20VDC on your multimeter, then put the black tip onto a generic ground, and the red one on pin 10 of U1. You should measure around 5VDC. You can check also pad 5V on the PCB, or whatever point you like (such as the two bypass capacitors, C1 and C2).

Of course you have to power on the console.

Other test: connect the SCART cable to the console side (not to the TV/scaler). Select the diode symbol on your multimeter and check if you have continuity between SO on the PCB and pin 20 of the SCART head. It doesn't matter the orientation of red tip and black tip this time.

Just want to point out that I'm not here to teach people how a multimeter works. But I can help you for sure, we're here to help each other.

Let us know the progress.

[infidelity]

Thank you! Still not outputting video but here are my results.

Ok, so I did exactly what you said. I put the black on part of the metal edge of the motherboard as a ground. And used the red tip for testing all my points.

Everything was registering values, the AV solder points, the vdp where i soldered my r,g,b,csync wires, and my newly located 5v. However, both ends of my GND from the rgb bypass to the CXA did not give any readings.

Where should I relocate the GND? And would that be the reason for no picture?

Also, my 5v is registering 4.95.

Edit: I also checked all the other parts on your board.

Idk if this supposed to happen, but I got no reading when touching either side of these resistors.

R32, R22, R12. (I think those are r's, hard to read) again, that's from me testing both ends of those resistors. All the other parts I touched on the board, registered values. I still need to know where to find an alternative GND location?

The multimeter was set to this symbol...
__
...
V

Edit 2: tested S0, and pin 20 of my euroscart cable with system on. Both outputted 2.76 on my multimeter using continuity.

And again, those 7 resistors you told me to remove on the bottom of my motherboard, do those need to be bridged? Because they are open after I removed the resistors, the solder points are not touching eachother.

[ApolloBoy]

Also if your using comp video for sync you WILL get a picture but it will have no sync. Don't listen to that other guy

That's what happens when you post half-asleep kiddos.

[ApolloBoy]

Where should I relocate the GND? And would that be the reason for no picture?

Your ground connection is fine where it is, highly doubt that's the reason why you're having problems.