Tech - Williams Joust PCB Repair #2 - CPU RESET

From start to finish, all the steps taken to repair another William's Joust arcade PCB.

DO ALL REWORK AT YOUR OWN RISK
I am not a professional. This is a personal hobby, and I learn every day.

**NOTE**
All troubleshooting steps recorded, and this one was tricky. Please, take note of the annotations in the video.

For example, the 20k Ohm resistor used in this video is not enough for the circuit in question. It most certainly requires a 22k Ohm resistor for reliable RESET circuit operation. Otherwise, you risk rapidly toggling a transistor causing a flapping RESET to the CPU via 6F pin 3 in the Joust schematic. The capacitance charge timing is important on this circuit.

Also, I found that the 20 uf capacitor listed in the schematic does not reflect the actual 22 uf capacitor installed on the board. I replaced the original 22 uf capacitor with another 22 uf capacitor and did not use the uf value denoted by the schematic. The +5 vdc pull up resistor is verified to be originally 22k Ohm as found on another working and unmodified Joust board.

Lastly, I doubt I'm done with this power supply circuit and the CPU address bus. There are a couple components which may be replaced in the future; however, it is stable for the time being.

A future video will likely showcase the power supply circuit for Joust as well as a video covering CPU socket replacement.

If you have questions or would like a video covering a specific topic with regards to arcade repairs, please let me know.
A big thanks to Tothwolf @ John's Arcade Shoutbox for his time and interest in helping track this one down.

Chat with us:
http://www.johnsarcade.com/forum/index.php?action=shoutbox

Видео Tech - Williams Joust PCB Repair #2 - CPU RESET канала Strykhar's Arcade