Golden Tee Fore 2005 motherboard issue.flyby button stuck.

[mclovin]

Good day all, I have a golden tee 2005 green motherboard and everything a works just fine other than the flyby button is stuck on all the time, which actually makes it stuck looking up. It has nothing to do with the flyby button or jamma connection as another motherboard works perfectly when swapped.

Anyone have any suggestions on how to deal with this? I have a parts board that I can swap stuff from if need be, I just don't know where to start. Thanks!

[Malenko]

is the button wire on NC instead of NO? You say it cant be the button but, the issue describes sounds like the button is being held down, which usually means its wired to NC.

[mclovin]

Forgive me but I'm not sure what you are asking. Can the default NO and NC be adjusted somewhere? When I replace the pcb board with another one, there is no issues. When I connect this pcb all works fine except the flyby button is stuck on. It can't have anything to do with the wiring or the button itself because it works perfectly with another motherboard plugged in, including the flyby button. I'm guessing there must be a short on a chip or the board somewhere for this to be stuck on.

[Malenko]

so follow the wire from the button to the board to see where on the jamma loom it plugs in. Then check around that area on the board for any kind of short.




As for NO and NC, those are 2 of the 3 prongs on a switch, the 3rd being ground.

[PL1]

In addition to looking for shorts, look for attempted repairs.

It is very rare but possible for a repair to appear good when checking with a multimeter (very low power), but short to another trace when you power up the board.

The cause is not cleaning the board after soldering -- microscopic globs of solder can form an arc-path.


Scott

[mclovin]

I can't see any obvious shorts or previous repairs. Stumped.

[lilshawn]

switches have a NO or normally open and a NC or normally closed position.



when the button is NOT pressed down as it normally sits, the NO contact is not connected to the common tab and the NC contact tab IS connected.

when the button IS pressed, the NO contact is connected to the common tab and the NC contact tab is disconnected.

you may confirm the status of the switch by loading the switch test and seeing if the flyby button is registering properly. if it does, you might have something wonky going on in the software.

[Loopey1]

He said that when he switched out boards the issue went away. That should tell you all that its not a switch.
More than likely he has a Buffer issue on his board. Look for damage or burnt components near the edge connector. There are 3 chips IIRC 745's?? that act as input buffers. But before those there are a few resistors and a few SM caps.
If you have someone that has a SMD rework station and a new chip you can have them replaced quite easy. It takes about 5 min.

[lilshawn]

oh, you're right Loopey, I must have glazed over that part.

the inputs are handled by IC chips (74LS541 octal buffer and line driver) that pass the floating/low state of the input to the CPU, there may be some schmutz on or near the IC that handles the fly-by button input. something damp or sticky on the pins could cause the input to go low and read as being activated.

check all the IC's resistors,capacitors diodes between the IC's and the JAMMA connection and make sure it is free of spills.

otherwise, you'll need to replace the buffer IC.

if searching ebay or calling around for parts... search for "74LS541 SOIC" or "SN74LS542DW" you want the surface mounted SOIC version not the PDIP package.

in a pinch you could mount a PDIP in some veroboard and use some thin ribbon cable to solder onto the pads...the pinout layout is the same...just way smaller. it's not pretty but it can work.

[mclovin]

UPDATE: I left this board alone for a while and then thought I would tackle it again. Thanks for the help I got it fixed, there is a bank of  four 74LS541 surface mount chips, did some guessing and tracing and swapped the second one in from the video card and pow that got it.  You guys rock!

[lilshawn]

SCHWEEET! 

also if you have a dead input there are some small surface mount inductors right off the pins for the input pins...sometimes they will get zapped open circuit. you can either move one from a unused input or (if your crazy) bridge the component. but you may end up frying the IC if you get a static zap again there.