Wow!! I was absolutely shocked when I first saw those pictures of that mint untouched Sinistar cabinet still in the cardboard box. Never thought my mods would end up running on it! What an absolute honor, thank you Brad!
The capacitor in the 'Soft Start' is one part of an RC (Resistor/Capacitor) time constant. It provides a delay after the power is applied before taking the CPU (6809e in this case) out of reset mode. This ensures that all of the IC's on the board have clean and stable power before the CPU starts executing instructions. There is also some circuits that monitor the voltage levels (regulated +12 and +5) and will force a reset on the CPU if they get too low. The original linear power supply has a circuit that will 'crowbar' the power if it goes too high.
@@BradRaedel The Soft Start RC time constant has to be BEFORE the watchdog timer trips to take the CPU out of reset mode. The Soft Start RC circuit much "RESET" the watchdog timer circuit?
@@BradRaedel The Power Supply "Sensing circuit" on various pinball and arcade games causes problems because the wiring harness/connector pins cause resistance/voltage drop between the header pins to the connector pins. I'm not sure what this type of resistance is called? but there is a voltage drop that occurs from the header pin to the connector pins so it will drop the sensing voltage which trips the sensing threshold comparator to send a FORCED reset signal to the CPU
@@waynegram8907 The counters are also held in reset until the time constant runs out. Therefore, no watchdog since the 'MR'(Master Reset). Everything on the board comes out of reset at the same time. This allows synchronization and prevents collisions on the address/data busses.
@@waynegram8907 Williams arcade games don't use remote sensing for the linear power supplies. They decided to use heavier gauge wire with less voltage-drop and preset the values a bit higher (~5.1vdc regulated). at the source. The same reset circuit is used for both soft-start and low voltage monitoring on Williams MPU's.
Wow!! I was absolutely shocked when I first saw those pictures of that mint untouched Sinistar cabinet still in the cardboard box. Never thought my mods would end up running on it! What an absolute honor, thank you Brad!
Thanks Max! Yes, that NIB game is amazing! I'll give you some feedback when it's installed and the customer is playing!
Man, Sinistar is amazing, let alone a new in box one. I’ve got a pretty decent collection of Williams hardware, but no Sinistar stuff. Nice work!
Why do some arcade boards don't use soft start? the soft starting circuit is only a capacitor?
The capacitor in the 'Soft Start' is one part of an RC (Resistor/Capacitor) time constant. It provides a delay after the power is applied before taking the CPU (6809e in this case) out of reset mode. This ensures that all of the IC's on the board have clean and stable power before the CPU starts executing instructions. There is also some circuits that monitor the voltage levels (regulated +12 and +5) and will force a reset on the CPU if they get too low. The original linear power supply has a circuit that will 'crowbar' the power if it goes too high.
@@BradRaedel The Soft Start RC time constant has to be BEFORE the watchdog timer trips to take the CPU out of reset mode. The Soft Start RC circuit much "RESET" the watchdog timer circuit?
@@BradRaedel The Power Supply "Sensing circuit" on various pinball and arcade games causes problems because the wiring harness/connector pins cause resistance/voltage drop between the header pins to the connector pins. I'm not sure what this type of resistance is called? but there is a voltage drop that occurs from the header pin to the connector pins so it will drop the sensing voltage which trips the sensing threshold comparator to send a FORCED reset signal to the CPU
@@waynegram8907 The counters are also held in reset until the time constant runs out. Therefore, no watchdog since the 'MR'(Master Reset). Everything on the board comes out of reset at the same time. This allows synchronization and prevents collisions on the address/data busses.
@@waynegram8907 Williams arcade games don't use remote sensing for the linear power supplies. They decided to use heavier gauge wire with less voltage-drop and preset the values a bit higher (~5.1vdc regulated). at the source. The same reset circuit is used for both soft-start and low voltage monitoring on Williams MPU's.