Purchased a used arcade and need some advice.

[Starcraftunicorn]

Hey guys, i purchased a Dance Dance Revolution for very very cheap and it has been heavily modified so the schemes from the cab don't help me all to much. Right now my issue is the dance pads tho, I re-wired the pads for a standard molex connection and currently the pads are not reading from the machine test. What would be the best way to test each sensor individually along with the Pad I/O going tot he cabinet. I will post pictures. Let me know what the best would be to check the signal coming from the pads.

 

[KeepItSimpleStupid]

A couple of things.

There needs to be a minimum amount of current to help clean a switch contact. A good number is 10 mA. That's a rule of thumb.

I am suggesting De-Oxit for cleaning and actually put a current through the switch to help clean them. That would just be a power supply, resistor and switch in series.

But before you do that, what i would do is:
Check the voltage across the switch, then activate it and see if it changes.
An example, you may find 5V across the switch and when you activate it manually, it drops to a few mV.
If the switches are scanned, all bets are off.

Knowing the schematic gives you a better way to test.

I'm giving you some background info when I don't know any better. it's very possible that the designers didn't either.

Testing the voltage across the switch when pressed and unpressed is a little unusual for a novice. Activating the switches a few times may also work. Actvation clean the contacts, opening and closing the contacts under load does too. If the load is too small, it's not possible to break through the oxide. Activating it multiple times when on is a good 1st try.

 

[Starcraftunicorn]

Thanks for the information, Were you talking about something like this?

 

[KeepItSimpleStupid]

That may be how the sensors are interfaced. Take an example of a switch, incadesent lamp and resistor and a power supply in series.

When you measure across the switch with the switch off, you get the power supply voltage.
When you measure across the switch, with the switch on, you measure the voltage drop of the switch. It contains the contact resistance. It should be near zero.

That's where you should start, there could be reasons why this method won't work. If you have high contact resistance, activate the switch multiple times and look for improvement.

Now start looking at the ability to clean the contacts or loose connections. Jump out the switch. etc.