Hi all ,
Purchased some months ago a faulty original KFM pcb from a member on here,nice overall condition .I was informed that the game boots but has graphics issues.
So here goes and time to fire it up.............
Well
theres definetly graphic issues and very severe,good points is that the game program is running.I can coin up and play but cant see any sprites or text,also noticed some speech sounds are missing such as the death sound when you loose a life.
Something tells me this KFM pcb has a lot of issues.This KFM pcb is a 3 stack board set,G board(top),A board(middle) and B board(bottom).
Luckily i have a working KFM pcb original so i can use its pcbs on the faulty one to narrow down the faults.I started out on looking at the G board(top) as i think its responsible for the tiles,text and layer graphics generation.On this board set there are 2 nasty custom chips KNA6032701 and KNA6032601 which ive seen on many repair logs seem to fail.Removed this pcb and fitted it to my working KFM pcb and fired it up and it still showed crap on the screen but interestingly i can just about see moving sprites.So this confirms that the G board has a fault,decided to remove the 2 customs and put in new sockets.I then removed the 2 customs from my working G board and fitted to my faulty G board.
Ok now lets fire it up..............
well it looks no different? so the good news is those 2 customs are good ,Decided to poke around near the customs with my scope and check outputs on logic chips until i stumbled across a LS157 where its output at pin 4 was floating.
Removed this chip and i put in a new socket with a new LS157,fired it up and...............
Thats cool i now have all the tile,text,layer graphics back ,still no sprites .To make sure this pcb was working 100% i fitted it to my working KFM pcb and it worked perfectly so this board is fixed.
To be continued...........🥋
Purchased some months ago a faulty original KFM pcb from a member on here,nice overall condition .I was informed that the game boots but has graphics issues.
So here goes and time to fire it up.............
Well
theres definetly graphic issues and very severe,good points is that the game program is running.I can coin up and play but cant see any sprites or text,also noticed some speech sounds are missing such as the death sound when you loose a life.Something tells me this KFM pcb has a lot of issues.This KFM pcb is a 3 stack board set,G board(top),A board(middle) and B board(bottom).
Luckily i have a working KFM pcb original so i can use its pcbs on the faulty one to narrow down the faults
.I started out on looking at the G board(top) as i think its responsible for the tiles,text and layer graphics generation.On this board set there are 2 nasty custom chips KNA6032701 and KNA6032601 which ive seen on many repair logs seem to fail.Removed this pcb and fitted it to my working KFM pcb and fired it up and it still showed crap on the screen but interestingly i can just about see moving sprites.So this confirms that the G board has a fault,decided to remove the 2 customs and put in new sockets.I then removed the 2 customs from my working G board and fitted to my faulty G board. Ok now lets fire it up.............. well it looks no different? so the good news is those 2 customs are good ,Decided to poke around near the customs with my scope and check outputs on logic chips until i stumbled across a LS157 where its output at pin 4 was floating. Removed this chip and i put in a new socket with a new LS157,fired it up and............... Thats cool i now have all the tile,text,layer graphics back ,still no sprites .To make sure this pcb was working 100% i fitted it to my working KFM pcb and it worked perfectly so this board is fixed.To be continued...........🥋
