Hello guys.
I have a Dodonpachi Resurrection PCB I bought about 10 years ago.
It's been working fine until recently, but has some problem now.
When I try to power it up, it doesn't turn on for a few times and then it just turns on.
I experienced other cave PCB shows the same problem and died in the end, so I'm a liitle concerned about this.
Is there any way to repair it?
Thanks for reading.
My Cave PCB's booting is unstable
-
yonggarri
- Please Continue...
- Posts: 7
- Joined: September 30th, 2020, 11:20 am
- Location: South Korea
- eBay: Yonggarri
- Initials: YSJ
-
Sunder
- Posts: 325
- Joined: August 31st, 2017, 12:13 pm
- Location: Slovakia
- eBay: sunderaj82
- Initials: SUN
Re: My Cave PCB's booting is unstable
Im about 85% sure it's the SMD chips lifting off the pads.
-
buffi
- Posts: 137
- Joined: May 4th, 2009, 4:52 pm
- Location: Sweden
- Contact:
Re: My Cave PCB's booting is unstable
I am also quite curious what causes this, since I own a Muchi Muchi Pork with similar issues.
Something youve seen yourself?
Ive been assuming some cap is going bad, but i havent spent much time investigating.
Whats your reasoning for thinking that?
Something youve seen yourself?
Ive been assuming some cap is going bad, but i havent spent much time investigating.
-
mikejmoffitt
- Posts: 28
- Joined: May 28th, 2012, 2:35 am
- Location: Tokyo, Japan
- eBay: 7raster
Re: My Cave PCB's booting is unstable
Make sure the 32.768MHz crystal near the CPU is solid too. if it's missing, the board will repeatedly reset. You can see this from the red CONF_DONE LED pulsing very slightly during reset.
Otherwise, the board gives no indication that the CPU is running until it has finished configuring the FPGA and began executing the game out of RAM.
A few things that are possibly stopping boot, that I have encountered and had to fix in the past:
* Simple TSOP or QFP solder breakage, as suggested in this thread
* Bad main RAM acting unreliably (the IC between the FPGA and the long edge of the board)
* Bad FPGA connections, due to trace rot/damage/possible BGA fracture (I have replaced the FPGA once, it was not that bad ultimately)
The CPU boots off of the program flash, bootstraps the FPGA by sending it a bitstream, copies the main game program into RAM, and then executes from there. What it does after that varies from game to game, but usually involves loading of a lot of graphics data from the larger flash into video RAM while doing some other tasks.
If the boot is unreliable, but it always remains solid once it is actually going, then maybe start by inspecting the NOR flash at U4 for poor connection to the pads.
Otherwise, the board gives no indication that the CPU is running until it has finished configuring the FPGA and began executing the game out of RAM.
A few things that are possibly stopping boot, that I have encountered and had to fix in the past:
* Simple TSOP or QFP solder breakage, as suggested in this thread
* Bad main RAM acting unreliably (the IC between the FPGA and the long edge of the board)
* Bad FPGA connections, due to trace rot/damage/possible BGA fracture (I have replaced the FPGA once, it was not that bad ultimately)
The CPU boots off of the program flash, bootstraps the FPGA by sending it a bitstream, copies the main game program into RAM, and then executes from there. What it does after that varies from game to game, but usually involves loading of a lot of graphics data from the larger flash into video RAM while doing some other tasks.
If the boot is unreliable, but it always remains solid once it is actually going, then maybe start by inspecting the NOR flash at U4 for poor connection to the pads.