I followed the mmmonkey tutorial. I Lift leg 12 of original chip. Then solder the new chip on top, leaving leg 1, 12, 44 and 23 up and not attached to the old chip. I Connect lifted leg 44 of new chip to pin 7 of the adjacent chip per instructions. Lifted leg 1 is connected to lifted leg 23 (is this correct?) And the resistors and power is all hooked up the same way as the va1 chips, correct? The resistor connected to let 12 of old chip is connected to the top leg of the new chip? Mmonkey tutorial seemed vague about that. Wasn't totally sure if it's supposed to be attached to the old or new chip. When I turn the console on, the retail bios works fine, but there's a blank screen when I try to run the hacked bios. TV says no signal. Can someone please help me? I've done this many times on VA1 boards, but this is my first time trying it on a va0 and I'm not sure what I did wrong. THanks. *Edit. All of the legs soldered to the old chip have been checked with a continuity meter. So those are all solid connections.
*Updated* Another user was having a simular problem, his power source wiring was incorrect but it was a direct replacement mod I think this is the way it should be (but of course with your case, with the resistors in place) this might be the case but i would wait intill bad_ad84 comes around. FIRST try this, Solder pin 23 of the new chip to the old chip IF that doesnt work, i think this might work but remember to keep the resistors in their place but i would really recommend you wait intill bad_ad84 comes around to confirm it Solder pin 23 of the new chip to the old chip PIN 44 to PIN 23 PIN 1 to PIN 7 on IC502 (the VIA point) http://www.assemblergames.com/forums/attachment.php?attachmentid=4375&stc=1&d=1347542183 If that doesnt work, you did you check for continuity with a multi-meter?. it might be one of those times that the solder didnt attach to one of the legs properly or a bad solder joint.
Before I hooked everything else up, I went around to every leg that is attached to the old chip with a continuity meter.
I'm doing the dual bios also. Leg 44 gets wired to that tiny point connected to leg 7 of the chip next to it. I'm not sure what's going on in that picture. Looks like they have leg 1 wired to that tiny point instead.
http://www.assemblergames.com/forums/showthread.php?41619-VA0-Dreamcast-link83-bios-replacement-help this is a direct replacement mod the reason he has pin 23 lifted for the va0 mod is because he was using a VA1/2 chip and trying to source v3.3 power from another location which didnt work, but in your case you have a 5V chip so you dont need to do that. so first try to solder pin 23 of the new chip to pin 23 of the old chip with resistor in place, etc. Sorry about the editing its been a long night
Oh wow. Thanks a lot Zer0. I got it to work. I just had to connect pin 23 of the new chip to the old chip. I guess if I wanted to rewrite the new chip, I would have to swap those two wires from leg 44 and 1. I wonder if we can get the mmmonkey tutorial updated to reflect this. I'm so happy I got this done tonight for my customer. I'm moving to a new another state tomorrow morning and was hoping to ship this off before I leave. Thanks again for the help!
you need to swap pin 1 and 44, the 5v chip used in the VA0 is different to the VA1 (pin1 and 44 are swapped). I will update the guide on mmmonkey, just waiting for him to give me the correct permissions to edit posts other than my own.
