Quantcast

Results 1 to 8 of 8

Thread: Model 1 Mega Drive only works in Master System mode

  1. #1
    Raging in the Streets Thierry Henry's Avatar
    Join Date
    Dec 2008
    Location
    SA
    Posts
    3,098
    Rep Power
    95

    Default Model 1 Mega Drive only works in Master System mode

    The issue with this system is that there is no indication that it is turned on (led light does not light up at all) and there is no sign of life either when any MD cartridge is inserted.
    But as soon as you use the PBC with a Master System game, those games play flawlessly.

    What would make it do this?
    Quote Originally Posted by soviet View Post
    We believe! SEGA Empire will live again! As the Jews re-established their Israel, GOD will never forget his people, SEGA will never forget her fans!

  2. #2
    Comrade as in friend. Master of Shinobi ComradeOj's Avatar
    Join Date
    Dec 2012
    Location
    New Mexico, USA
    Age
    25
    Posts
    1,342
    Rep Power
    57

    Default

    Some of the pins needed for Genesis games could be dirty. Have you tried cleaning the cartridge port? You can DIY it by stretching a microfibre cloth around a credit card with a little 90% rubbing alcohol on it. Work it between the pins in the cartridge, but be gentle and don't snag any pins on the cloth. A safer slower way might be to put a little alcohol on a game cart's pins and insert and remove it a few times, drying the cart pins with a q-tip and repeating a few times.

    Another thing people do is re-tension the pins to make stronger contact. You should be able to find guides to do this online, but usually it involves tweaking the pins a bit with a tiny screwdriver.

    SMS mode is activated by grounding a certain pin on the cartridge port. I think it's more likely that some of the pins required to play Genesis games just aren't making contact, but the smaller number of pins needed for SMS games are okay.
    Modded consoles:
    Master System (v7040) with s-video & direct AV out
    Model 1 with 10mhz overclock & halt switches
    Model 1 with 10mhz 68010
    Model 2 VA2.3 with unfiltered Mega Amp, & s-video
    Model 3 VA1 with compatibility fixes & s-video
    32X with s-video
    Visit my web site at www.mode5.net
    Or my collection of homebrew Genesis games, programs, and music on SEGA-16!

  3. #3
    Video Game Modder Outrunner segasonicfan's Avatar
    Join Date
    Nov 2009
    Location
    California
    Posts
    601
    Rep Power
    20

    Default

    Quote Originally Posted by Thierry Henry View Post
    The issue with this system is that there is no indication that it is turned on (led light does not light up at all) and there is no sign of life either when any MD cartridge is inserted.
    But as soon as you use the PBC with a Master System game, those games play flawlessly.

    What would make it do this?
    wow, I never would've thought to try SMS games if the Genesis didn't boot regular games. That's actually kinda brilliant.

    +1 with ComradeOJ. I've had the best success cleaning cartridge slots by using isopropyl alcohol with a good acid brush (you want something stiff like horsehair). a cheap $1 magnifying glass (they have 10X ones I think for $3) is a great investment for looking at dirty card slots and other electronics, too.

    Did this break under your care, or was it a thrift store find?

  4. #4
    Raging in the Streets Thierry Henry's Avatar
    Join Date
    Dec 2008
    Location
    SA
    Posts
    3,098
    Rep Power
    95

    Default

    Quote Originally Posted by segasonicfan View Post
    wow, I never would've thought to try SMS games if the Genesis didn't boot regular games. That's actually kinda brilliant.

    +1 with ComradeOJ. I've had the best success cleaning cartridge slots by using isopropyl alcohol with a good acid brush (you want something stiff like horsehair). a cheap $1 magnifying glass (they have 10X ones I think for $3) is a great investment for looking at dirty card slots and other electronics, too.

    Did this break under your care, or was it a thrift store find?
    From a local auction site. This was bundled with some other items as a "non-working lot". For the equivalent of about $10.

    With regard to the power light not lighting up. I took the top cover off with that LED and connected it to a Model 1 Genesis. The light comes on. It's functional, so I'm not sure why it doesn't light up when connected to that Mega Drive.

    So as to the cart slot. It's clean. I used Isopropyl alcohol on a cloth wrapped around an old debit card I had lying around. Didn't seem to make any difference. MD games still don't work. There is a brief flash on the screen when you power it on. But that's it. Just a black screen afterwards.
    I'll try with a brush and see if that helps any.

    But yeah as I said, Master System games work fine. As do Mark III carts and Sega card based games.





    One thing I noticed on the board. Some of the pins around the 315-5313 chip look a bit corroded. Would that maybe have anything to do with it?
    Last edited by Thierry Henry; 05-21-2019 at 05:34 AM.
    Quote Originally Posted by soviet View Post
    We believe! SEGA Empire will live again! As the Jews re-established their Israel, GOD will never forget his people, SEGA will never forget her fans!

  5. #5
    Video Game Modder Outrunner segasonicfan's Avatar
    Join Date
    Nov 2009
    Location
    California
    Posts
    601
    Rep Power
    20

    Default

    I took a look at the schematic for ya, and it looks like the LED is powered on if you have VCC2. That is a 5-volt rail generated from one of the 7805s, IC17 depending on your board revision:
    https://gamesx.com/wiki/lib/exe/fetc...stom_chips.png

    check to see if you have 5 volt there or if it's shorted to ground. My guess is if you replace that chip you'll be in business as long as there isn't a short. It would be kind of fascinating if Sega designed the system to power Master System games solely of VCC1. Maybe an interesting legacy design choice from SMS.

  6. #6
    Hedgehog-in-Training Hedgehog-in-TrainingSports Talker
    Join Date
    Sep 2015
    Posts
    37
    Rep Power
    0

    Default

    I have an MD similar to this.
    Mine will not play Mega Drive games but work fine in Master System mode.
    The LED is fine on mine though.
    I worked out that the problem on mine is the 68000: It's burned out!
    There is a slight discolouration in the middle of the CPU.

    I took out the 68000 and now MS games still work (!) and there are less random glitches.
    I suppose replacing the CPU will fix MD mode here.

  7. #7
    Raging in the Streets Thierry Henry's Avatar
    Join Date
    Dec 2008
    Location
    SA
    Posts
    3,098
    Rep Power
    95

    Default

    Quote Originally Posted by rama2 View Post
    I took out the 68000 and now MS games still work (!)
    You'd have to confirm with the tech guys here but I think the 68000 shuts off when in SMS mode.
    Quote Originally Posted by soviet View Post
    We believe! SEGA Empire will live again! As the Jews re-established their Israel, GOD will never forget his people, SEGA will never forget her fans!

  8. #8
    Comrade as in friend. Master of Shinobi ComradeOj's Avatar
    Join Date
    Dec 2012
    Location
    New Mexico, USA
    Age
    25
    Posts
    1,342
    Rep Power
    57

    Default

    Quote Originally Posted by rama2 View Post
    I have an MD similar to this.
    Mine will not play Mega Drive games but work fine in Master System mode.
    The LED is fine on mine though.
    I worked out that the problem on mine is the 68000: It's burned out!
    There is a slight discolouration in the middle of the CPU.

    I took out the 68000 and now MS games still work (!) and there are less random glitches.
    I suppose replacing the CPU will fix MD mode here.
    The 68K sits idle when running SMS mode. I'm not sure if it gets thrown in an idle loop or halted somehow though.

    I've played SMS games on my working Genesis systems and haven't had any glitches. Having a damaged 68K might have been doing weird things to the hardware in one way or another, and removing it stopped whatever was going on.
    Modded consoles:
    Master System (v7040) with s-video & direct AV out
    Model 1 with 10mhz overclock & halt switches
    Model 1 with 10mhz 68010
    Model 2 VA2.3 with unfiltered Mega Amp, & s-video
    Model 3 VA1 with compatibility fixes & s-video
    32X with s-video
    Visit my web site at www.mode5.net
    Or my collection of homebrew Genesis games, programs, and music on SEGA-16!

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •