They should be a starting point when diagnosing problems. I rechecked the power supply output voltage and now its 5.58v!Īfter adjusting the power supply voltage so the game was getting at least 5.1v, I powered it down and back up again to verify game operation, I rechecked the voltage at the power supply and saw it was a whopping 5.58v! As we can see there is considerable voltage drop between the power supply and the game boards. In the above pics I’m taking voltage readings from the Jamma connector then from the cable that sends power to the main game board. Here I’m measuring the voltage from the cable to the main game board. It’s hard to see but the probes are on the +5v and ground edge connector traces. I turned the voltage up on the power supply +5v adjustment knob and brought it to about 5.12v. Unfortunately I didn’t take a picture when initially measuring voltage at the Jamma harness but it was only 4.38v which is way too low. The game would freeze when attempting to spin the DVD player since it was starving for power. Tekken 4 uses Sony’s Magic Gate system which is essentially a PlayStation. Also when attempting to play a game it would freeze.

I rechecked the output from the power supply and observed it was still 5.1v. When the game powered up it worked ok for a few minutes then started to lock up. I make the initial setting 5.1v, this is a safe place to power up the game and make adjustments from there. This will send 110v to the “9 pin” power supply, the monitor and the marquee light fixture which is tapped off the input side of the isolation transformer.īefore connecting the power supply connector to the game harness I wanted to check the voltage. All I did was modify the wiring to match a plug I installed in the cabinet.

With the original power supply modified I can re-install it back into the cabinet. Gutted and rewired for use with a new “9 pin” power supply. This keeps the functionality and location of the power switch as well as to not leave a gaping hole in the back of the cabinet. I took out the original unit to take it apart to remove the internals and modify it to work with my new unit. Its not a big deal since I just replace it with a standard “9 pin” power supply. These fail quite often and I’m honestly not sure if an equivalent of the same size and form factor is still available. In servicing a dead Tekken 4 I noticed it had one of the large power supplies mounted to the middle of the rear of the cabinet. Either way you almost always start with the power supply.Ī weak or malfunctioning power supply will cause all kinds of problems, especially intermittent ones. When restoring video games or pinball machines some of the work you do will be to repair problems, others are preventative maintenance.

Tekken 4 arcade