Results 1 to 20 of 33

Thread: Sharp NES freezing up

Hybrid View

Previous Post Previous Post   Next Post Next Post
  1. #1
    ServBot (Level 11) Custom rank graphic
    Cornelius's Avatar
    Join Date
    Jan 2007
    Location
    Wrong Place, Wrong Time
    Posts
    3,778
    Thanks Thanks Given 
    72
    Thanks Thanks Received 
    25
    Thanked in
    24 Posts

    Default Sharp NES freezing up

    I'm having problems with my Sharp NES system freezing up. Some games seem completely fine, my kids played Bubble Bobble for a really long time no problem, for instance. SMB doesn't seem to have any problems. SMB3 seems okay, but I didn't play it for long enough to really know. However, other games I've tested with freeze up right away, like Contra, which always froze on the first level. Dr. Mario seems to work okay for like 30 minutes and then it freezes, sometimes having some glitches for a little while before that (e.g. pills coming while something is still falling, or pieces not falling when they lose support).

    These games work fine on separate NES systems.

    Games load easily on the SharpNES, but I also cleaned the pins and have installed a BLW, neither of which helped at all.

    I looked around and people with similar problems have been told to replace the voltage regulator. Thought I was good after doing that, because I played around 5 levels of Contra without issue, but then it froze again. Still freezing on Dr. Mario. Next up are capacitors, so I replaced the three on the power supply, and 3 of 4 on the main board. The 4th one isn't labeled with polarity, so I'm not sure what to do about that one, just left it for now. With that all done, no change on the freezing up front.

    Any suggestions? I could go after that last capacitor and just put it in the way it would be on a regular front-loader. I'm thinking I need to start looking at chips, but I can't see any way to do that. There is certainly no easy way to power the thing with it open/accessible.

    Here's the board and cap in question pointed out:



    Last edited by Cornelius; 04-29-2018 at 03:22 PM.

  2. #2
    ServBot (Level 11) Custom rank graphic
    Cornelius's Avatar
    Join Date
    Jan 2007
    Location
    Wrong Place, Wrong Time
    Posts
    3,778
    Thanks Thanks Given 
    72
    Thanks Thanks Received 
    25
    Thanked in
    24 Posts

    Default

    Here's the two boards next to each other. I was thinking maybe I could do a swap or something, but that seems well beyond my capabilities.


  3. #3
    Great Puma (Level 12) jb143's Avatar
    Join Date
    Nov 2007
    Location
    St. Louis
    Posts
    4,246
    Thanks Thanks Given 
    5
    Thanks Thanks Received 
    69
    Thanked in
    62 Posts

    Default

    Quote Originally Posted by Cornelius View Post
    I could go after that last capacitor and just put it in the way it would be on a regular front-loader.
    Unless they drastically changed the board design(and it doesn't look like they did) then they should be the same. There is also such a thing as an non-polarized electrolytic called a bipolar capacitor...but I would lean more toward the first option.
    "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...

  4. #4
    ServBot (Level 11) Custom rank graphic
    Cornelius's Avatar
    Join Date
    Jan 2007
    Location
    Wrong Place, Wrong Time
    Posts
    3,778
    Thanks Thanks Given 
    72
    Thanks Thanks Received 
    25
    Thanked in
    24 Posts

    Default

    I'm thinking that's what it is, actually. It has "B P" prominently printed below the specs. Thanks for pointing me that way. Now, since I don't have that cap, can I replace it with a polarized one like it is on the front-loader? I'll do some reading.

    Quote Originally Posted by jb143 View Post
    Unless they drastically changed the board design(and it doesn't look like they did) then they should be the same. There is also such a thing as an non-polarized electrolytic called a bipolar capacitor...but I would lean more toward the first option.

  5. #5
    Great Puma (Level 12) jb143's Avatar
    Join Date
    Nov 2007
    Location
    St. Louis
    Posts
    4,246
    Thanks Thanks Given 
    5
    Thanks Thanks Received 
    69
    Thanked in
    62 Posts

    Default

    It's weird that the regular front loader calls for a standard electrolytic and yours calls out a bipolar. But if it's on the board then they must have had a reason. Typically those caps are used if the design calls for an unpolaraized cap but the capacitance is too large for ceramic caps to be available/cheap enough
    You can make an unpolaraized by tying 2 electrolytics in series (+ together I believe, you'll want to verify that). You'll use the series calculation to get your values(which is the same as the resistor parallel calculation). It's likely to be some value that's hard to find and may not fix your issue. At any rate, digikey and mouser should have an exact replacement.

    That cap looks to be part of the lockout chip. Can lockout issues cause freezing like you're seeing or just the blinkies?
    "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
    ServBot (Level 11) Custom rank graphic
    Cornelius's Avatar
    Join Date
    Jan 2007
    Location
    Wrong Place, Wrong Time
    Posts
    3,778
    Thanks Thanks Given 
    72
    Thanks Thanks Received 
    25
    Thanked in
    24 Posts

    Default

    Quote Originally Posted by jb143 View Post
    It's weird that the regular front loader calls for a standard electrolytic and yours calls out a bipolar. But if it's on the board then they must have had a reason. Typically those caps are used if the design calls for an unpolaraized cap but the capacitance is too large for ceramic caps to be available/cheap enough
    You can make an unpolaraized by tying 2 electrolytics in series (+ together I believe, you'll want to verify that). You'll use the series calculation to get your values(which is the same as the resistor parallel calculation). It's likely to be some value that's hard to find and may not fix your issue. At any rate, digikey and mouser should have an exact replacement.

    That cap looks to be part of the lockout chip. Can lockout issues cause freezing like you're seeing or just the blinkies?
    I saw that trick with the two caps in series and may do that, you just get a component with half the capacitance. But I'm suspecting bad ram or other chip. I may try to hook it up so I can feel the chips during operation to see if on is getting hot. Bad idea?

  7. #7
    Great Puma (Level 12) jb143's Avatar
    Join Date
    Nov 2007
    Location
    St. Louis
    Posts
    4,246
    Thanks Thanks Given 
    5
    Thanks Thanks Received 
    69
    Thanked in
    62 Posts

    Default

    How is power being fed into the board. I would assume a transformer replacing the AC adapter and everything else is more or less the same? Are you able to take measurements when it's running? To make sure it has a steady 5 volts before and during the freezing? Notice any smells when it's been running for a while? When you replaced the regulator did you add any thermal grease? I'd also search for tips on checking for a bad CPU.

    Sorry I can't be of more help, I'm not familiar with the Sharp NES TV at all. If nothing else, I can give you ideas to try until someone who knows what they're talking about shows up
    Last edited by jb143; 04-30-2018 at 03:50 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...

Similar Threads

  1. SNES Freezing?
    By zdirty in forum Technical and Restoration Society
    Replies: 1
    Last Post: 03-04-2010, 10:13 PM
  2. ps3 bluray freezing
    By c0ldb33r in forum Technical and Restoration Society
    Replies: 2
    Last Post: 06-09-2009, 08:36 PM
  3. xbox 360 freezing
    By Daft Punk in forum Technical and Restoration Society
    Replies: 4
    Last Post: 12-07-2008, 02:51 AM
  4. 32x freezing
    By gamegirl79 in forum Technical and Restoration Society
    Replies: 5
    Last Post: 10-30-2003, 08:45 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
  •