RF with Rev C board: Dead. Replaced Z80, 1 broken resistor pack next to the Z80, and resoldered a few surface mount customs.
RF2 with the Rev D board: Hardware Error 82. Resoldered surface mount customs and the Yamaha sound chip. Board then booted to a Checksum Error. Pulled the surface mount flash chip, changed the first memory location to 0x10h, then reinstalled the flash chip. Board booted fine. Installed the RF cart to ensure system would rewrite flash properly. Tested. Installed the RF2 cart again and let it reflash again. Tested.
T'wasn't too hard to do once I had the TSSOP to DIP adapter. Oh, and once I rewired the damn adapter. It was set up with the wrong pinout! The SMT flash has pin 1 on the corner of the chip and the adapter had pin 1 on the middle of one side instead. GRRRR!
Notes...
- If the Z80 is bad it won't boot.
- Hardware Error 82 went away when I resoldered the custom IC next to the Z80 on the Rev D board.
- Poor soldering on the pesky custom next to the 386 CPU will keep the board from booting.
- To pull a surface mount TSSOP chip load up the pins with a big blob of solder. Heat the solder and slowly lift up with an Xacto knife. Alternate sides and after a few times of heating and lifting alternate ends the chip will finally lift off. GO SLOW or you'll pull solder pads and render the board toast.
- Clean the pads well on the board. Use liquid rosin flux on the ends of the chip, turn it upside down and use your soldering iron to remove the excess solder from the chip leads.
- If you don't do that upside down then you'll leave too much solder on the bottom of the chip leg and it won't seat properly on the pads when you go to solder it back in.
- Use the liquid flux to help solder the chip in place and remove bridges from between the 1/2mm pitch pins.
- Curse when you look and see that you soldered it in 180 degrees out of place (I got it right the first time
)
