Thanks for the suggestion. My edge connector is not so bad, some soldering has been done on the +5V, but nothing major. I already cleaned up the P1 control pins this weekend but it did not fix the B button issue. I will have to look at the TTL, resistor arrays and traces involved when I have some free time.@sylphia
Something I noticed looking at my board, yours may be different. But my edge connector is absolutely filthy and covered in gunk, particularly the middle section of pins. If yours is the same this could explain the second button not functioning correctly. It may also help improve your sound. Not sure if it will help with the background issue you're having though.
have you checked the 68000 CPU with your scope ? At least the part related to the work RAM ?Survey says! No dice.
Still doing the exact same thing. I also noticed if I remove the ROMs completely now, it does the exact same thing just with no garbage on the screen. It seems to be locked in some kind of test mode. The good news is that it is trying to boot.
Edit: I just ran my scope across the sound section and that's not firing up at all. Everything is low. I don't even know where to start on this giant thing :/ there's no obvious broken traces, nothing to prevent it from booting (which is I assume why it's just running this endless loop of garbage) - it's possible that it's because I've doubled it up on a 27C040 and it doesn't want to run that way, so I need to wait until 27C020 chips arrive to test this theory.
What does strike me as unusual is that with no main program ROMs installed initially it just froze on a static screen which would make sense to me, where now it still keeps trying to run. I'm thoroughly confused at this point.
@Hammy and @Hatsune Mike
If you get an opportunity to have a look at the code above for 1.bin - I would be interested to see what you think.
I actually got the same reaction with the original/bootleg mixture, both original or now both bootleg.Excellent! Thanks for the dumps!
I will check them out later, the sound roms still are interesting, don't forget them
The original rom was most likely crashing because you had mixed the original and bootleg roms.
Hi,So I've dumped another 2 of the EPROMs on this board and replaced a dodgy looking socket for one of the main program ROMs (no, that didn't make it fire up sadly)
I have dumped the 27C020 (on this board an M27C2001) device at 1C (right next to the Yamaha - I'm assuming this is the sound ROM) and the 27C010 (Intel 27C010A) in the dead centre of the board
I still have the 2 16Mbit mask ROMs to do (I thought there was just 1, but there's a second one underneath a board with 2 PALs on it which is going to be an absolute nightmare to remove), and the other 27C010 in the sound section (I'm assuming this is the Oki data) but I want to socket all the ROMs rather than solder them back in place and I ran out of 32 pin sockets (as well as not having any 42 pin for the 16Mbit chips)
@sylphia - the 27C010 might be the tile data? Or possibly the fix layer? (I'm assuming tile data will be quite large so maybe that's in the 16Mbit masks)
When you get a chance would you be able to verify these against your set to determine if they are good dumps or not (or potentially if one of yours is bad) and hopefully this might fix some of your issues