Game I/O port issues

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Joined: Dec 13 2016
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Any game I try to play with joystick support seems to be stuck in one position regardless if the joystick is plugged in or not. I checked the values running a BASIC program reading PDL(0) and PDL(1) and they are both maxed at 255, moving the joystick has no effect. Could this be due to a bad capacitor or chip? I have a spare Apple II that I can use to swap parts, but would appreciate any guidence on which things would be worth swapping to test. Thanks

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speedyG's picture
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Joined: Nov 16 2011
Posts: 2376
Re: Game I/O port issues

Hello jpxl8ed,

entering the term "gameport" in upper right searchfield would have
listed this thread:
http://www.applefritter.com/?q=content/gameport-fault
aand my reply ( posting #1 ) would have been the answer to your question....
speedyG

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In early days I had a lot of money but no time - now I have no money but a lot of time....
the second part includes less friends but a lot more joy on life....

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Joined: Dec 13 2016
Posts: 12
Re: Game I/O port issues

Thanks for the help. I did search, but somehow missed the most obvious first entry.. oh well anyways, it's much appreciated. I will follow the advice you posted and try replacing some of the components there first.

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Joined: Dec 13 2016
Posts: 12
Re: Game I/O port issues

I have followed all the advice in the link to the other thread. I replaced all the related capacitors and resistors along with purchasing a new NE558 and none of it seems to have made any difference with or without the joystick plugged in. Any other suggestions of where I should look?

speedyG's picture
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Posts: 2376
Re: Game I/O port issues

Hello jpxl8ed,

2 thoughts:
if both paddles or axis of the joystick are making similar mistakes
there might be a problem with continuity between pin 8 ( GND )
at the Apple II or pin 3 ( GND ) at the //e and the joystick/paddles....
and what about + 5 Volt at pin 1 (II) or pin 1 at //e and the joystick/paddles....???
check for continuity.....
any pictures from component side and solder side of the related areas
( NE558 and or 15pin DIL Connector ( at II )or DB9 connector ( //e ) ???
http://www.appleii-box.de/H040_NibbelingAtTheGameport.htm
or:
http://www.appleii-box.de/H043_AppleIIGamePortPages.htm

sppeedyG

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In early days I had a lot of money but no time - now I have no money but a lot of time....
the second part includes less friends but a lot more joy on life....

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Joined: Dec 13 2016
Posts: 12
Re: Game I/O port issues

I'll check and see what the reading is on pin 1 along with the checking the continuity on 8 and 3. So even with nothing plugged into the game port a loss of continuity on pins 8 or 3 could cause the PDL reading to always be 255? Here are some pictures of the game port area of the board as it is now.







speedyG's picture
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Re: Game I/O port issues

I have seen several of this white sockets wear out and getting bad contact.

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In early days I had a lot of money but no time - now I have no money but a lot of time....
the second part includes less friends but a lot more joy on life....