N64 Z Button Non-Functioning

[ChristianKirbo]

Heyo! I somehow broke my Z button on my N64 controller a few years ago, and I am finally getting around to fixing it up. The problem is, there is not apparent physical damage to the trigger itself. The Motherboard is okay, the magnetic sensor is okay, and the controller itself is okay. However, The only thing that comes to mind when I am thinking of what went wrong was years ago when I played on a console that had an expansion pack in it. After about a year, it infected all of the other Z buttons on every single other controller that was used on it. I know it is that console specifically because it will not infect other controllers on my system if I plug it in. Does anybody have a solution that would not require buying replacement parts? Please let me know as soon as possible.

Thanks,
ChristianKirbo

 

[KiiWii]

I don’t know how an expansion pak could cause damage to the Z triggers of every pad attached to it... unless it was a third party one and the voltages fried then somehow?

 

[ChristianKirbo]

Like I said above, there is no physical damage, so something must have affected the motherboard or something in one way or another, I dunno. Another thing could have to do with the power cable not transferring energy to the Z button, and it somehow makes the game think that the Z button is pressed. Btw, this doesn't work for any game, Goldeneye, Mario 64, DK64, or anything. I just tested

 

[FAST6191]

Infect is probably the wrong word. The N64 controllers are very unlikely to have any random logic in there which could get overwritten a la virus or similar. For modern ones that have their own firmware that is another thing but back then.
An expansion pack with a short sharing the same power source as a controller (not the best design decision but within reason) and shorting out buttons, lines on the control chip or something is far more plausible and would fit with it killing multiple controllers and them staying dead across multiple systems. Not sure why Z is the thing that died, other than it probably being held for longer in games and thus being more prone or perhaps it just being first in line as it were and the thing that pops first. Never heard of such a thing for the N64 but that means little.

Shorting things and burning out something also poses a different problem as diagnosing such things. Take resistance measurements between various points on a known good board until you find something different then being what you have to do. Hopefully it is just a trace or something you can jump rather than any onboard chips or the carbon film switch things. Depending upon what goes you might also be able to jump the Z button switch leads as they head back to the chip/controller port into something else (small wire going to one of the other buttons and pressing Z and say Start or something firing would indicate the switch aspect works and it is instead a part of the chip).

 

[ChristianKirbo]

Ok, Fast. Here is what I found out:
I plugged the controller into the N64 with the motherboard exposed.
I took a voltmeter and measured the voltage for that type of button.
The A, B, and C-Buttons have the same sensor, so I stuck those.
They all read 6.4 Volts (ironic that it's the N64.)
The Z button only read 0.1v at the very bottom of the wire and on the sensor.
This tells me that there might possibly be a broken saunter joint in there somewhere, and that the Z button isn't getting the proper power that it needs to in order to function properly. This is good information for troubleshooting, so just let me know if this is correct. I am kind of new to the sport of modding and repairing controllers.

 

[ChristianKirbo]

here are the voltages for the various buttons:

 

[FAST6191]

Going with voltages? Fair enough and it is low voltage DC (not like you are probing live mains voltage or worse). I normally do resistances but as a great man once said "first rule of troubleshooting is thou shall measure voltages" and it is not like the two concepts are unrelated.

6.4V is an odd one -- most logic levels are anything but that (see Logic-family switching levels, 5V or maybe just about 3.3V I would expect for stuff of that vintage, else a full 12 or 15 for some oddities) but without knowing otherwise I will accept it. Multimeters of that style (they occasionally have as slightly different shell but that is a fine example of the cheap and nasty multimeter that most people getting into this sort of thing get at first and ultimately regret later down the line when they have a go on something shinier) also have a very nasty habit of being that kind of out of range too, though in any case that stark a difference is enough to note in this.

A low voltage at a similar point would point to a high resistance somewhere along the path, one that would break a button functionality. For it to happen to multiple controllers in short enough a period (even more so as Z button failure is so very rare in general) does however cause me to think short circuit making something go pop where I would expect dry solder joints to be more of a various points over years, mechanical stress (which could be a controller but most things I see are worse than that still) and possibly temperature ranges (I often see it in car switches, which may also do high current in the case of electric windows).
At the same time looking at https://upload.wikimedia.org/wikipedia/commons/7/7d/Nintendo-N64-Controller-Motherboard-Flat-Top.jpg I am seeing what looks like both corrosion and dry or maybe cold solder joints so maybe.

Simple switches work in one of two ways.
They either cause a voltage to be applied to a pin (pull up) or for the ground to be applied to a pin (pull down). This is why if you follow the circuit traces all the buttons will probably have a common point where they all join up on one side of the switches (do also be sure to measure both sides -- if geometry changes then you don't want to be measuring the wrong part of the switch, one of the reasons why resistance can be easier to do).

Looking at that image you might be able to short each side of the Z pins out (if you have the chip readable as in that image in front of you then by the copper triangle in the bottom right I am guessing is where the Z button board comes in and see if the system displays Z as being pressed. You may or may not want to use a fairly low value resistor here (carbon trace switches have a bit of their own resistance which has some effects in this sort of circuit, see floating voltages if you are curious, though for a short test a wire will probably be OK). In a strict test you would be desoldering one of the wires (in case the whole thing had shorted closed and in essence made the button think it was pressed the entire time*) but you might be able to skip that here.

*ever had to unplug and replug a controller because someone held the stick during startup? Same idea.

 

[ChristianKirbo]

Do you know where to get a good resistor? I think that this is telling me that I need more equipment, and I would need a solder joint repair mechanism to do this. But that HUGE thread does help me greatly, thank you @FAST6191

--------------------- MERGED ---------------------------

So I basically need a resistor, and something to repair the solder joints. Do ya know where I can find those? That HUGE thread does help greatly though, FAST6191.

 

[FAST6191]

The resistor is more of a test thing.
If you have broken device you can strip for parts it will likely have several dozen in of various values.
If not they sell them in packs of several hundred of many different flavours in electronics shops.


The resistor itself is more of a possible thing needed for a test -- solder one between the pads on the board and all you will do is make it think it has been pressed all the time. Testing here would involve touching one pad to the other via the resistor (or maybe just some wire) and seeing if the console sees it as an input.

"Solder joint repair tool" is a soldering iron and some solder -- the fancy videos online might have hot air and IR to melt/reflow things but they are more tools of convenience and for doing more modern approaches than anything on the controller. Heat it up, maybe flow some more solder in there and it should be good (nice and shiny, no cracks around the thing being connected, not bridged onto another device unless you know it needs to be). If you really want to push the boat out then you can get a solder sucker and some solder wick too. If you plan to take up electronics in earnest then definitely but for a simple one time repair you can probably skip it (wick is just strands of copper, if you need to remove solder then normal copper wire will do at least something there.
I hesitate to suggest it if you are not already familiar with soldering irons but if push comes to shove then you can heat a nail up (don't use a galvanised/verzinken one as zinc fumes are no fun) and use it as one -- your grandad probably was used to soldering irons that are little more than that*. I am not sure it is that, or is solely that, but if the wikipedia picture was anything to go by it is an option. Should be simple enough to test the controller with a wire/resistor before then too.


*you put one of these in a fire, wait a while and then use it until it cools and you repeat the process

 

[ChristianKirbo]

So, to sum everything up, I just need to solder (or fuse) the Z button solder joints using some sort of hot iron piece, and press it until they melt together, or do I need to just heat them up but not join them together? I tried to figure it out, but with no luck. Sorry, I'm inexperienced, but I like to make sure I know what I am doing before I do it (logic? yes.) I would rather take word from a "Techromancer" rather than a "Newbie."

--------------------- MERGED ---------------------------

Actually, I just did a cost analysis: it only costs $8 or a mother board on e-bay (i don't know if the UK has it but anyways
I think that it would just be easier to buy a whole new one and install it, just because money versus time and labour is more appealing than risking a break or damage on the old motherboard. Anyways, thanks for the help, but it would just be easier to buy and replace instead.

 

[ciaomao]

Guys, this multimeter should be in DC mode, not AC. Not sure if mentioned already

 

[ChristianKirbo]

Oh..... I just looked at the picture.... :| *cough*

 

[The Real Jdbye]

Going with voltages? Fair enough and it is low voltage DC (not like you are probing live mains voltage or worse). I normally do resistances but as a great man once said "first rule of troubleshooting is thou shall measure voltages" and it is not like the two concepts are unrelated.

6.4V is an odd one -- most logic levels are anything but that (see Logic-family switching levels, 5V or maybe just about 3.3V I would expect for stuff of that vintage, else a full 12 or 15 for some oddities) but without knowing otherwise I will accept it. Multimeters of that style (they occasionally have as slightly different shell but that is a fine example of the cheap and nasty multimeter that most people getting into this sort of thing get at first and ultimately regret later down the line when they have a go on something shinier) also have a very nasty habit of being that kind of out of range too, though in any case that stark a difference is enough to note in this.

A low voltage at a similar point would point to a high resistance somewhere along the path, one that would break a button functionality. For it to happen to multiple controllers in short enough a period (even more so as Z button failure is so very rare in general) does however cause me to think short circuit making something go pop where I would expect dry solder joints to be more of a various points over years, mechanical stress (which could be a controller but most things I see are worse than that still) and possibly temperature ranges (I often see it in car switches, which may also do high current in the case of electric windows).
At the same time looking at https://upload.wikimedia.org/wikipedia/commons/7/7d/Nintendo-N64-Controller-Motherboard-Flat-Top.jpg I am seeing what looks like both corrosion and dry or maybe cold solder joints so maybe.

Simple switches work in one of two ways.
They either cause a voltage to be applied to a pin (pull up) or for the ground to be applied to a pin (pull down). This is why if you follow the circuit traces all the buttons will probably have a common point where they all join up on one side of the switches (do also be sure to measure both sides -- if geometry changes then you don't want to be measuring the wrong part of the switch, one of the reasons why resistance can be easier to do).

Looking at that image you might be able to short each side of the Z pins out (if you have the chip readable as in that image in front of you then by the copper triangle in the bottom right I am guessing is where the Z button board comes in and see if the system displays Z as being pressed. You may or may not want to use a fairly low value resistor here (carbon trace switches have a bit of their own resistance which has some effects in this sort of circuit, see floating voltages if you are curious, though for a short test a wire will probably be OK). In a strict test you would be desoldering one of the wires (in case the whole thing had shorted closed and in essence made the button think it was pressed the entire time*) but you might be able to skip that here.

*ever had to unplug and replug a controller because someone held the stick during startup? Same idea.

N64 controllers do indeed run on 3.3V.

 

[FAST6191]

Sorry. Should have caught the meter being in AC mode. Cheap meters might well double it if they are doing the absolute basic type of sensing and that would be in range for 3.3V in that case.

Anyway if a replacement board works for you then do that. You might have to do a bit of soldering though.

Bridging the solder joints is only a test and does not need you to solder anything. By bridging the pads by the triangle with a resistor/wire you effectively close the switch. This will confirm the chip still accepts an input from the Z button (high voltages might only burn up a single track -- does not have to make the whole controller stop working). If that is the case you either need a replacement chip or board (chip repair is not really a thing anybody does outside of some specific scenarios that are not this).
After this you would then take the wire, place it on another button test point and power the other side of the z button. With that in place press the Z button (or hold it down throughout) and see if the test point for the the button you are using fires instead. This will act as a test of the switch itself.

The soldering part is in case any of those joints have become dry joints (dull in colour and maybe with a fracture around the pin being soldered) or corroded (usually get a nice blue/green colour) over the years. No soldering anything to them in that case. Just heating up the joints so they melt and maybe putting a bit more solder on there if you think some fresh will help (the picture I linked before had several without much there).