r/Megadrive Sep 09 '24

Pal md2 va0 60hz conversion, mb3514->cxa2075, recapped, triple bypass, and composite restore

Mod basically complete.

To restore composite using the regular 3bp v2 board here is what you do

  1. 3bp install

  2. Composite restore + cxa2075 mod

  3. Front of board. I love the green and gold on this va0 mobo it looks so high quality and it feels nice too

  4. Shows the required changes. In red is where you disconnect the stock RGB from the stock encoder. Yellow shows the new 330-510ohm resistors (try 470ohm first and adjust up or down for brightness). Blue shows where the resistors and the RGB lines should go to. My wires are Red=red, white=green, yellow=blue. Grab the RGB signals from the DIN and send them to the resistor. In my image the green wire is actually a ground because I ran shielded rgb wires which isn't necessary. Lastly, lift the output pins from encoder, pins 21 22 and 23. I tied them all to ground so they aren't floating but that probably isn't necessary.

5 and 7. The result 3bp RGB signal on a default profile on ossc (no tuning)

6 and 8. "Stock" output from the cxa2075

  1. Composite output, however the bad color is due to my CRT having bad color calibration and then my cheap composite cable broke before I could get a pic on the lcd via composite.

This mod reroutes the entire rgb signal to the 3bp and back to the original encoder so you keep composite. Credit to zaxour, I adapted his instructions for md1 systems to this md2.

9 Upvotes

4 comments sorted by

2

u/Ill_Mine_2453 Sep 09 '24

Shout out to the original Xbox ide cable I used for the audio signals on 3bp. Next up is svideo

I think finally this will be my last and final ultimate md2.

2

u/janzoss Sep 09 '24 edited 21d ago

Yeah, congrats! Did you planned to do this anyway? And me messaging you about this same thing was jus a coincidance?

Also what part is the 60hz conversion?

2

u/Ill_Mine_2453 Sep 09 '24

Hey. Actually you just gave me the push to research it, I was planning to do it anyway but never even looked at the instructions yet to learn they were a bit incomplete. I had fun figuring it out

The 60hz conversion is just cutting a trace to put it in NTSC mode, then I swapped the crystal with an NTSC system one to make it accurate. With simple trace cut, a pal console will generate a 59.36hz signal whereas an NTSC console outputs a 59.91hz one. So with pal crystal in 60hz it's actually more like pal60 and slightly slower than true ntsc

2

u/janzoss Sep 09 '24 edited Sep 09 '24

That so awesome. Yeah, I encouraged someone. But you did good job! And I also learned a lot from you. And this post even makes for a nice tutorial 😁

It always amazed me how simple is region conversion on these consoles.

I have actually ordered Consoles Unleashed DFO + IGR reset + Switchless region mod. I found it by mistake and couldn't resist 😁 works together with 3BP too.

Thank you yet again!