System: NEC Turbografx-16 (HES-TGX-01)
Power supply: Manufacturer's OEM (HES-ACA-01)
SD Card / Cable: Purchased from Stoneagegamer.com at the same time as the SSS3. (Purchase date 4/1/2019)
Settings: "Per game backup RAM" and "Enable Arcade Card" checked, all others unchecked.
FW Version: 01.02 R05, FPGA C498
Playing any game, Hucard or CD, from the SSD3 will eventually cause a crash of the Turbografx. If the game is playing CD audio, the SSS3 continues to play the audio track even though the game has frozen (which may or may not also have screen corruption). Seems to always happen within 10 minutes.
I sold most of my games to get the SSD3 so I only actually have the Keith Courage cart to test. If I boot up the Hucard (with the SSS3 still attached), the system runs for at least an hour with no issues.
Last night, if I booted Keith Courage from the SSD3, it will crash after a few minutes. This morning, it seems to be working OK. Ys4 , however is still showing graphical corruption.
The SSS3 case does not appear to be correct for the American Turbografx-16 console. It was impossible to install as shipped. The SSSD3 pin connector does not line up with the pins on the TG16, and the SSS3 connector needs to be raised up by at least 0.100" to get onto the expansion port pins. (This unit had a Turbobooster connected to it for almost 30 years, which just came off when I received the SSSD3 yesterday. None of the pins looked bent in any way, shape, or form, which I inspected before attempting installation.)
To get around this, I removed the unit from its shell, installed the board in the TG16, and put the shell back on, tightening the two rear screws but only loosely turning in the front two screws. I will need to order some #4 washers and put them between the bottom case and the PCB, so that the screws can be properly tightened.
My proposed plan of attack for system instability:
1. Recap the Turbografx-16. (It's almost 30 years old, after all - parts have been ordered.)
2. If the recap doesn't fix the problem, instrument the incoming power from the power supply, and the 5V rail inside the Turbografx at the CPU. (I have a Lecroy HDO4032 at home.) The LM7805 used on the Turbografx has a 2V dropout and ~150mV worst case regulation. The oscilloscope should be able to capture minimum voltages. Replace power supply filter capacitor if the incoming power drops below 7.25V, replace 7805 if regulation is out of whack.
3. If everything seems fine on the voltage rails, I'll probably have to send it in for service.