Single Switch Region Mod

[omp]

Wow that seems rather odd.... Maybe your iron is to cold? Or the solder to thick? You could make sure the oscillators legs are clean. You could use fine sand paper (speaking 1200 grit+ here) to clean any crap off it, just lightly run the sand paper 1 or 2 gentle swipes is all. Also have you wired the oscillator correctly? the pin that has the squared off end isn't connected.

I have put away the MD2 that I done for Game Traders, however I have another MD2 on it's way hopefully be here soon. I do have a dead MD2 here that I can take pics of the board where you can test to be sure you have disabled the relevant pins.

What revision board have you got? It shouldn't matter as this fix I have done is the same/similar as MD1 (uses 2 pin oscillator) as well as Nomad (as I have put up elsewhere on these forums).

[omp]

I recently got a va2.3 & va3 boarded gen 2's. Would there be any objections if I put up pics on how to do single switch for these revision boards? I had a quick look tonight at the va3 and it looks to be very easy.

[EreWeGo]

I do have a dead MD2 here that I can take pics of the board where you can test to be sure you have disabled the relevant pins.

What revision board have you got? It shouldn't matter as this fix I have done is the same/similar as MD1 (uses 2 pin oscillator) as well as Nomad (as I have put up elsewhere on these forums).

Cool, thanks omp, if you have time mate. I haven't desoldered and started again yet, but will do soon, just to double-check the connections, as well as make sure I've disabled the pins correctly etc.

What's strange is that I noticed if I touch the wire from the oscillator to R61, (the clock to R61), then the Eu colour/flickering is fixed. At first I figured it must be a bad solder, and that it was the pressure of me touching the wire that was making the connection, but it seems it's more like me touchinh the wire is grounding it... I'll have to re-check everything I think, starting from scratch...

[EreWeGo]

Success!!! Hey omp, had another play today, desolder a few points that I suspected may be the issue, and resoldered the two points from the voltage regulator to the oscillator, (I actually soldered to the "O" and "G" lega of the regulator directly, rather than underneath), and now getting full colour in all modes!

Thanks so much for your help mate, you're a legend!

BTW, my board was a v1.8 PAL

[omp]

No worries, glad you got it going. I had a look today and I have a VA0, VA1 and VA1.8 MD2 here. The mod is the same for all these and the test points to ensure that pin 6 and 7 are disabled are the same. Since I took a pic, I may as well upload it if anyone does this and has a problem.



With this pic, you need a multi-meter (continuity) and test between pin 7 (video encoder MB3514, CXAxxxx) to point as shown and R61 (which goes to pin 6 video encoder) to point as shown. If it buzzes recheck your cut tracks. Pin 7 runs to pin 46 of the Sega 315-xxxx chip which is the same pin you use for the 50/60Hz mod (obviously).

Again good work in getting it going!

[EreWeGo]

Thanks for the pic omp, will help with testing future mods.

BTW, have you tried this colour-fix mod for the Megadrive 1:
http://www.retro-otaku.com/2010/07/p...e-and-s-video/

I have a Megadrive 1 with working single-switch mod, and tried this colour fix mod, but I can't seem to get colour in US or Jap modes? Checked the connections, and since cutting the trace, if I remove the new oscillator 5v or R23 wire as a test, then I get no colour in Eu, (which I assume shows that the cut trace is definitely cut....

I might need to start a new thread for this, but if you've tried this mod and have any tips that'd be awesome.

[omp]

Oh ok try this one, easier to find components. On that one I have to say rule number 1 is broken. Video related wires should be kept as short as possible.

This is what I use.



Disable the tracks to these pins (5,6, 7) from underneath or if you are daring cut and lift (not recommended but it's what I usually do).

Honestly I can't count how many times I have done this, a bare minimum of <a lot> and it works EVERY time! I even have pre-made boards done!

Here is a pic of how the board I make sits in the console.



Just remember keep the wires short.

[EreWeGo]

Damn,
nice work omp, you're a wealth of knowledge my friend!
Where did you source the 50pF trim capacitor?

[omp]

I got mine from Jaycar (well Jaycar's supplier). https://www.soanarplus.com/default.jsp?xcid=1

There is a seller on ebay, if you type this in "Trimmer Capacitors 9.8pF - 50pF". From Romania.

[EreWeGo]

Thanks mate, if you get a sec, do these look suitable?

http://www.ebay.com/itm/Trimmer-Capa...item5ae5a070de

http://www.ebay.com/itm/30-x-30pF-50...item3a6883929c

http://www.ebay.com/itm/10-pcs-4-433...item1c21b23932

http://www.ebay.com/itm/30-x-Resisto...item41615efcac

[omp]

All are fine except the oscillator, make sure with the seller it is 4.433619Mhz. I am not 100% sure if that would work, just be safer to get one that is listed as the full description.

[EreWeGo]

Thanks mate,

the only 4.433619Mhz ones I could fine are the "taller" profile ones, like this:

http://www.ebay.com/itm/2-4-433619-M...item2319cd3aa1

http://www.ebay.com/itm/5-PIECES-NEW...item4aabf05e8e

http://www.ebay.com/itm/NEW-4-433619...item3f0dfce4b0

Would they still suit?

One last question: Since you have some "pre-made", any chance of a pic of the back of the boards you made?

[omp]

Taller ones are fine, not a problem. I had one board left, so here it is.

[EreWeGo]

Thanks omp, you're a star mate, very much appreciated!

[raylyd]

Hi can we do this for the sega nomad as i have a new lcd and would like to region mod it and 50hz is black and white.?

Oh ok try this one, easier to find components. On that one I have to say rule number 1 is broken. Video related wires should be kept as short as possible.

This is what I use.



Disable the tracks to these pins (5,6, 7) from underneath or if you are daring cut and lift (not recommended but it's what I usually do).

Honestly I can't count how many times I have done this, a bare minimum of <a lot> and it works EVERY time! I even have pre-made boards done!

Here is a pic of how the board I make sits in the console.



Just remember keep the wires short.