Didn't notice that. Deffo won't be the sockets then.They all seem to be soldered.I really need to check which are the sprites and try to piggy back some legit good chips and check for my luck.
You do need better equipment to trace this fault.
Toki Bootleg - No sound.
- Thread starter daeds
- Start date
You do need better equipment to trace this fault.
For that an Oscilloscope am I right?
Nothing else I can tinker with to see if I revive it?
Thanks a lot for all the help Lurch.
You could get by with a logic probe but it all depends on what the actual fault is.
Hopefully it's just a bad reset.
Only other thing I can suggest is checking the solder side of the PCB to see if any pins have bent in such a way to make contact with something it shouldn't.
Hopefully it's just a bad reset.
Only other thing I can suggest is checking the solder side of the PCB to see if any pins have bent in such a way to make contact with something it shouldn't.
I've checked and everything is okay with the solder side of both boards, have cleaned all the connectors and such aswell and nothing,
If it is a bad reset, how do I proceed to fix it?
You need to check if the reset is working before you attempt to fix it.
From the pictures it appears it's using a 68000 CPU which means the reset is pin 18.
You need a scope or logic probe to see if it goes high after power is applied to the PCB.
From the pictures it appears it's using a 68000 CPU which means the reset is pin 18.
You need a scope or logic probe to see if it goes high after power is applied to the PCB.
It's the motorola chip, right?
If it really goes high on the logic probe, how can I fix it? (Sorry but I'm really new to all of this, you've been a godsent help!)
If the reset goes high then it's OK.
The system should set it low on power up and then after a few milliseconds it will go high so the CPU can start running.
If the reset is at fault it can be held low so the CPU cannot run.
Or it's never held low so the CPU doesn't reset properly.
Don't worry about asking questions. I was in your position once.
The system should set it low on power up and then after a few milliseconds it will go high so the CPU can start running.
If the reset is at fault it can be held low so the CPU cannot run.
Or it's never held low so the CPU doesn't reset properly.
Don't worry about asking questions. I was in your position once.
Oh, got it! But if it stays low I have to buy another one to replace am I right? Or it can be something that triggers that "high" instruction that died aswell right?
I really appreciate the patience!
Pin 18 (reset) is an input.
There will be a part of the circuit that starts low on powerup that's connected to pin 18. This circuit is then designed to bring the reset high after a short time.
It will probably be part of the watchdog circuit (look it up) as well.
There will be a part of the circuit that starts low on powerup that's connected to pin 18. This circuit is then designed to bring the reset high after a short time.
It will probably be part of the watchdog circuit (look it up) as well.
My logic probe should arrive this week, will let you know after I analyze it. Thank you so much, really hope I can fix this one, it's one of my favorite games. :\
Yeah, these bootlegs are a bit different it seems, even with the sound.
Yeah, any idea what could've happen? I just forced the connections of the 2 boards like I always did and boom, it fired up, after 3 or 4 failed tries before.
The sprite errors seem worse though, I don't know why, I just soldered a new oscillator so it could sync on my TV and the missing caps for the sound.
I tested a bit more and I see that the board should have 2 power connectors, one in the front as it is and another one like it at the back, someone bridged the cables at the front connector and removed the one at the back, they put a cap instead I imagine to stabilize the current a bit.
It seems that this sprite issue is voltage related as I tried with another a bit more powerful PSU and the garbling is a bit less noticeable,
As my supergun uses 24pin connectors I use ATX power supplies that can't have their voltage regulated, how can I manage this? It seems that the voltage drop is too much from the connector to the sprite RAM that is underneath near the end of the board, can I add some caps in the middle of the second board to try and stabilize the current a bit more?
Thank you!
It seems that this sprite issue is voltage related as I tried with another a bit more powerful PSU and the garbling is a bit less noticeable,
As my supergun uses 24pin connectors I use ATX power supplies that can't have their voltage regulated, how can I manage this? It seems that the voltage drop is too much from the connector to the sprite RAM that is underneath near the end of the board, can I add some caps in the middle of the second board to try and stabilize the current a bit more?
Thank you!