BCS - Hardware Notes

Some notes from testing

D1/D2 LEDs

 * D1/D2 blink once at the same time means things are good and it should boot
 * D1 is on, D2 is off, means no/bad bios
 * D1 blinking, D2 is on, means no game
 * D1 blinks once, then D2 blinks once, then both blink at the same time, repeat. This seems to indicate an issue with the SDRAM.  It will likely be one/both of the modules nearest the jamma connector.  It can happen on the SDRAM near the cart slot, but that seem to more likely show it self as LEDs never come on.
 * D1/D2 never come on. This can indicate an issue with the SDRAM near the cart slot or something larger is wrong.

Misc Stuff

 * A game is required to boot.
 * Board has no problems booting if the SRAM is missing/bad
 * Variable Resistor VR1 adjusts RGB levels
 * Once powered it can take 10-15 seconds before audio/video show up
 * There is a bit of side to side wiggle room between a bare cart board and cart slot which can result in a short to ground when you power on the unit. With the jamma connector facing you, you want to insert the cart such that its butted up against the left side of the cart slot.
 * The plastic motherboard cover and cartridge case don't fit well together. Its very difficult to insert a cart and near impossible to remove it.  You are better off removing the motherboard's cover and just plugging the cart directly into the motherboard.