Everdrive and my Japanese VA4

So, I still haven't figured out why the Everdrive won't play SMS games on my Japanese MegaDrive version VA4 board. It plays SMS games fine when through a power base converter, so I know it CAN play SMS games. But not via an Everdrive.

My American VA3 Genesis works just fine.. Why not the Japanese system?

 

Oh, and before anything is said, NONE of these consoles are modified.

 

have you tried reflashing the firmware, or using a different version?

 

probably hard reset doesn't work on your system. necessary for hot switch between genesis and sms mode

 

Is it a bug between all VA4's? This VA4 MegaDrive was new old stock, I literally was the first person to power it up, a few months ago. Before then it was still in the box. I can't imagine it being broken unless it's a design flaw.

 

I would be surprised if you're the only one using an everdrive on a VA4. I'll be sure to test on my Genesis VA4 later when I have a chance.

 

it is a problem of your sample, not whole VA4

 

by the way, check if all resistors on front side of cart, near to edge connector, has same value. should be 101. wrong resistor may generate such problem in theory

 

Of your cartridge? I can't, stone age gamer used game bits, I can't open the cart. But being it works fine on a VA3 I'm not sure it's the cart.

 

That's too strange. I need to find another VA4.

Teancum, did you try your VA4?

 

Power on reset has been tested, it functions fine.. Shorting out capacitor C64 yielded a good POR condition on Genesis games, but SMS games STILL don't load..

 

Any particular reason for wanting VA4?

 

It's the only Japanese system I have, and frankly, I'm not getting another one.

 

Yeah probably cost less to get an SMS than that. after shipping from Japan for sure.

 

Teancum, did you ever try your EverDrive on your JP VA4? I REALLY need to know.

 

He has an American VA4. Not JP.

My JP is VA2 so I can't help you.

 

Out of sheer thought, I tried another PSU, one with a lot more amperage but same polarity and voltage, but that didn't work either, but it did get rid of some hum on the sound.

I'm out of ideas.. I know the SMS mode works, so I can't imagine why the Everdrive wouldn't.

I'm pondering a total recap.

 

Which pin on the Mega Drives cart slot is the one that puts the Mega Drive in SMS mode?

I think I may have found the problem, but don't want to say anything just yet.

 

Found the pin, B30..

A capacitor on the bottom of the board, a surface mount, looks like it may be mostly open.. Too bad without knowing what the value is supposed to be, I don't think I can fix it.

 

not only b30, address 20 should be pulled to vcc, and address 21 to gnd