Page 1 of 2 12 LastLast
Results 1 to 20 of 36

Thread: Fixing a SEGA Master System help!

  1. #1
    Insert Coin (Level 0) Custom rank graphic
    toploaderleo's Avatar
    Join Date
    Sep 2011
    Posts
    47
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    1
    Thanked in
    1 Post

    Default Fixing a SEGA Master System help!

    So yea, a few years back I tried to power my SEGA Master System with an NES Power supply and blew it. Sooooo since then I havnt been so stupid and also I wasnt in a good state of mind that day. So years later Ive decided to try in fix it (after not finding another one for dirt cheap) But I really have no idea what could be wrong with it. So far Im going over each connection with a continuity tester seeing if I blew a certain thing. Anyone know what I probably blew? Just to help me along.

  2. #2
    Insert Coin (Level 0) Custom rank graphic
    toploaderleo's Avatar
    Join Date
    Sep 2011
    Posts
    47
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    1
    Thanked in
    1 Post

    Default

    Could it be the transistor?

  3. #3
    Pretzel (Level 4)
    Join Date
    Sep 2005
    Posts
    819
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    0
    Thanked in
    0 Posts

    Default

    Check any Voltage regulators and fuses. You basically reverse biased the circuit. It may be fixable but I doubt if it is if it isn't one of the above.

  4. #4
    Insert Coin (Level 0) Custom rank graphic
    toploaderleo's Avatar
    Join Date
    Sep 2011
    Posts
    47
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    1
    Thanked in
    1 Post

    Default

    Any idea what an equivalent would be to the transistor? its says 73058 642K on it

  5. #5
    Great Puma (Level 12) jb143's Avatar
    Join Date
    Nov 2007
    Location
    St. Louis
    Posts
    4,242
    Thanks Thanks Given 
    5
    Thanks Thanks Received 
    66
    Thanked in
    59 Posts

    Default

    The power supply section should be at the left side of the board (under the power jack...and possibly covered by a metal shield?). More than likely the voltage regulator blew(the larger 3 legged black part with a metal tab). The pins should also be labeled ICO. I is "In", C is "Common", and O is "Out". If you put a voltmeter across O and ground you should get 5 Volts. You can replace it with a 7805 Voltage Regulator you can get at Radio Shack.

    Other things to test are the inductors JV and JG, they should each have a bit of resistance. You might even get away with using just a continuity tester...I'm not sure. Check all the electrolytic caps(the round cylinder parts). If they look bulged on the top then they're toast. Other culprits could be diodes in the power section.

    I hope this gets you started.

    Edit...didn't see your last post. That's the regulator. It's just a standard 7805 5 Volt regulator. Extremely common part.
    Last edited by jb143; 01-20-2012 at 12:56 PM.
    "Game programmers are generally lazy individuals. That's right. It's true. Don't let anyone tell you otherwise. Since the dawn of computer games, game programmers have looked for shortcuts to coolness." Kurt Arnlund - Game programmer for Activision, Accolade...

  6. #6
    Insert Coin (Level 0) Custom rank graphic
    toploaderleo's Avatar
    Join Date
    Sep 2011
    Posts
    47
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    1
    Thanked in
    1 Post

    Default

    Cool Im gonna go to radioshack tonight & pick up a 7805 then. thanks! I need to replace it anyway, it snapped off the minute I started messing with it.

  7. #7
    Banana (Level 7) fahlim003's Avatar
    Join Date
    Aug 2006
    Location
    The sinking old sanctuary
    Posts
    1,508
    Thanks Thanks Given 
    1
    Thanks Thanks Received 
    0
    Thanked in
    0 Posts

    Default

    It's most likely the regulator. Seems to be a common issue if the system isn't working.

    http://www.digitpress.com/forum/show...-Master-System

    Thankfully it's a cheap and easy fix. Best of success on the repair.
    Whaddya mean invalid parameters?!

    9,000 gigs of ram and it still can't answer a simple question!

  8. #8
    Pretzel (Level 4)
    Join Date
    Sep 2005
    Posts
    819
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    0
    Thanked in
    0 Posts

    Default

    Quote Originally Posted by toploaderleo View Post
    Cool Im gonna go to radioshack tonight & pick up a 7805 then. thanks! I need to replace it anyway, it snapped off the minute I started messing with it.
    Take a look for any scorch marks or signs of catastrophic failure, I have seen ICs where a hole was burned through it. Make sure to clean it up before putting in the replacement

  9. #9
    Insert Coin (Level 0) Custom rank graphic
    toploaderleo's Avatar
    Join Date
    Sep 2011
    Posts
    47
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    1
    Thanked in
    1 Post

    Default

    Well radioshack does carry the,m, just not in stores ' sooo Im gonna order one online. its cheap enough.

  10. #10
    Peach (Level 3) DogP's Avatar
    Join Date
    Mar 2003
    Location
    Manassas, VA
    Posts
    773
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    0
    Thanked in
    0 Posts

    Default

    Really? Every Radio Shack around here has the 7805... http://www.radioshack.com/product/in...ductId=2062599 (hit find in store). I picked up a dead SMS for $1 many years ago, and it just needed a 7805.

    DogP
    Virtual Boy Lives @ Project: VB

  11. #11
    Insert Coin (Level 0) Custom rank graphic
    toploaderleo's Avatar
    Join Date
    Sep 2011
    Posts
    47
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    1
    Thanked in
    1 Post

    Default

    I got one. I put it in. & the sega logo came up. Thrilled with joy I reassembled the whole thing. Now when I turn it on, I get the green led on but no game. The screen turns black then in a few seconds it blinks then it just stays black. At first I felt a shock from the sheild so maybeit had a short I re soldered the ends checked to see if I still got a connection, I must oif the LED is going on. It feels warm so maybe it just need to cool down for the night, Im not sure. But Im going to try agian in the morning. I hope I fixed it...

  12. #12
    Insert Coin (Level 0) Custom rank graphic
    toploaderleo's Avatar
    Join Date
    Sep 2011
    Posts
    47
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    1
    Thanked in
    1 Post

    Default

    Alright tried it again still nothing. It does the same thing with or without a game, and the built in game isnt working either.

  13. #13
    Pretzel (Level 4)
    Join Date
    Sep 2005
    Posts
    819
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    0
    Thanked in
    0 Posts

    Default

    There was always a good chance that an IC was fried too. Over-voltage and Reverse Biasing are the 2 worst things you can do.

  14. #14
    Insert Coin (Level 0) Custom rank graphic
    toploaderleo's Avatar
    Join Date
    Sep 2011
    Posts
    47
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    1
    Thanked in
    1 Post

    Default

    Yea but wouldnt it have not gone on at all before? Because after I replaced the 7805 it turned on and I got the game to start, but after I put the shell back on it wouldnt load games anymore, just urn on.

  15. #15
    Peach (Level 3) DogP's Avatar
    Join Date
    Mar 2003
    Location
    Manassas, VA
    Posts
    773
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    0
    Thanked in
    0 Posts

    Default

    You did cut the leads, right? If not, when you put the case together, you may be shorting the leads of the regulator on the metal shield. Other than that, maybe something else is causing the regulator to fry, and the new one is fried as well.

    I don't think so, but the original one didn't have a mica insulator (thin clear-ish plastic looking piece usually coated with heatsink goo) between the regulator and the large metal heatsink, right? If it did, you need to make sure you use that on the new one.

    DogP
    Last edited by DogP; 01-22-2012 at 09:27 PM.
    Virtual Boy Lives @ Project: VB

  16. #16
    Pretzel (Level 4) APE992's Avatar
    Join Date
    Jun 2007
    Location
    Chico, CA
    Posts
    999
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    0
    Thanked in
    0 Posts
    Xbox LIVE
    APE992

    Default

    Hopefully you only fried the 7805 you just installed.
    I fix things. You name it, I'll work on it. Want something modded? Recapped?

  17. #17
    Alex (Level 15) Custom rank graphic
    Gameguy's Avatar
    Join Date
    Dec 2008
    Location
    Richmond Hill, Ontario (Canada)
    Posts
    7,714
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    51
    Thanked in
    45 Posts

    Default

    Quote Originally Posted by toploaderleo View Post
    Alright tried it again still nothing. It does the same thing with or without a game, and the built in game isnt working either.
    Just wondering, what adapter are you using now? Did you get a proper Sega Master System one?

  18. #18
    Pretzel (Level 4) APE992's Avatar
    Join Date
    Jun 2007
    Location
    Chico, CA
    Posts
    999
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    0
    Thanked in
    0 Posts
    Xbox LIVE
    APE992

    Default

    Quote Originally Posted by Gameguy View Post
    Just wondering, what adapter are you using now? Did you get a proper Sega Master System one?
    FWIW you can use a model 1 Genesis adapter but as I found out as a kid doing it too often will cause the connector to break the solder joint away from the PCB trace. Thankfully it was easily fixed by adding a wire and some epoxy but still not a good idea.
    I fix things. You name it, I'll work on it. Want something modded? Recapped?

  19. #19
    Insert Coin (Level 0) Custom rank graphic
    toploaderleo's Avatar
    Join Date
    Sep 2011
    Posts
    47
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    1
    Thanked in
    1 Post

    Default

    Oh yea I have the original Sega Master System AC adapter. I was hoping all I had to do was replace the new 7805, I guess I couldve shorted it out cause I did cut the pins on the 7805 but I may not have cut them enough the 1st time, so i guess Ill go back to radio shack & buy a new one and hook that one up. I just wasn't sure if I had or not since the LED was still lighting up.

  20. #20
    Great Puma (Level 12) jb143's Avatar
    Join Date
    Nov 2007
    Location
    St. Louis
    Posts
    4,242
    Thanks Thanks Given 
    5
    Thanks Thanks Received 
    66
    Thanked in
    59 Posts

    Default

    Quote Originally Posted by toploaderleo View Post
    Oh yea I have the original Sega Master System AC adapter. I was hoping all I had to do was replace the new 7805, I guess I couldve shorted it out cause I did cut the pins on the 7805 but I may not have cut them enough the 1st time, so i guess Ill go back to radio shack & buy a new one and hook that one up. I just wasn't sure if I had or not since the LED was still lighting up.
    Do you have a volt meter? Because we could walk you through some troubleshooting. And would you mind taking a high res picture of the board? Also, did you take it back apart and see if it worked again that way?

    The LED means that power is getting to the LED...which is a good thing...but doesn't mean much as far as the rest of the components are concerned. The regulator(I'm assuming) getting hot usually means that something (like a short) is pulling too much power.
    "Game programmers are generally lazy individuals. That's right. It's true. Don't let anyone tell you otherwise. Since the dawn of computer games, game programmers have looked for shortcuts to coolness." Kurt Arnlund - Game programmer for Activision, Accolade...

Similar Threads

  1. Replies: 45
    Last Post: 10-29-2013, 01:17 PM
  2. WTB: Sega Master System Master Of Darkness
    By thegamezmaster in forum Buying and Selling
    Replies: 3
    Last Post: 03-20-2012, 04:24 PM
  3. Replies: 2
    Last Post: 11-30-2010, 04:05 PM
  4. Replies: 3
    Last Post: 04-03-2009, 12:24 PM
  5. FS: Samsung Gamboy system (Korean Sega Master System oddity)
    By ClubNinja in forum Buying and Selling
    Replies: 6
    Last Post: 10-05-2005, 10:58 AM

Posting Permissions

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