bacteria
n00b
- Joined
- Oct 23, 2010
- Posts
- 28
Ok, thought i'd see if my MVS-1B single slot NeoGeo MVS board worked. I understand from the manual that this board is rated at 3 amps at 5v and 1 amp at 12v; so to power the system i'm using a power supply from mains that outputs 4.16 amps at 12v, taking the 12v line directly to the NeoGeo and getting 5v from three 7805 regulators in parallel (which can output up to 1.5 amps each, so should be able to provide around 4 amps).
I know 7805's aren't efficient, I think they work at about 60% efficiency. The NeoGeo is probably the only system i'm going to have issues with in regards to amperage requirements.
The issue is that i've tried two game carts and both give the same results:
As you see, garbled graphics and also a band of black scrolls too.
I don't know what the issue is - I figure it might be one of the following scenarios, however I figured you guys would probably know the answer and help poor ol' Bac get his NeoGeo board working...?
* Not enough amperage, if the 7805's work at 60% efficiency then it might mean that i'm not getting 3 amps out of a 4.16 amp 12v supply. As the 12v line is for the audio requirements, I tried the system without the 12v line and got the same result, so might not be that - ?
* The MVS board I got from a chap in the USA, the cart from the UK and the PSone screen i'm using for testing (RGB mode): my understanding is the game carts are region free, and if the output was NTSC instead of PAL then i'd expect an image, squashed and scrolling.
* Something dead on the board - checked the capacitors, none are brown on top or misshapen to indicate they are dead, board visually looks fine.
* Dead board?? It was sold to be as "untested" hence cheap, although from a source that seemed ok
This is a pic of the system rigged up, the crocodile clips are soldered directly to 6 amp wires so not using the normal thin cable in crocodile clips.
Wired up as follows: (numbers are the traces on top, on the side with all the components, alphabetical letters are underside):
1: Gnd (pins 1 and 2 are shared)
3: 5V (pins 3 and 4 are shared)
6: 12v
12: Rgb
13: rgB
14: Gnd (video)
N: rGb
P: C-Sync
Didn't rig up the start, coins, direction or action buttons, or audio; all I wanted was a screen image initially (and not getting it at the moment).
Bottom line is if I can't get this board to work i'll abandon the NeoGeo in my project as i'm not paying about £80 for a replacement board on ebay and then a multicart for another £80 - I don't mind getting a multicart if my current board works, but not to pay double that!
Being the board it is, all the chips are soldered onto the board, the battery is a circular one raised off the board (so not a leaky battery), no traces appear to be broken or damaged on the boards.
So guys, i'd welcome your comments to help me get this board working, if in fact it is able to work. What does the screen image above indicate - faulty board, insufficient amperage, etc?
I know 7805's aren't efficient, I think they work at about 60% efficiency. The NeoGeo is probably the only system i'm going to have issues with in regards to amperage requirements.
The issue is that i've tried two game carts and both give the same results:
As you see, garbled graphics and also a band of black scrolls too.
I don't know what the issue is - I figure it might be one of the following scenarios, however I figured you guys would probably know the answer and help poor ol' Bac get his NeoGeo board working...?
* Not enough amperage, if the 7805's work at 60% efficiency then it might mean that i'm not getting 3 amps out of a 4.16 amp 12v supply. As the 12v line is for the audio requirements, I tried the system without the 12v line and got the same result, so might not be that - ?
* The MVS board I got from a chap in the USA, the cart from the UK and the PSone screen i'm using for testing (RGB mode): my understanding is the game carts are region free, and if the output was NTSC instead of PAL then i'd expect an image, squashed and scrolling.
* Something dead on the board - checked the capacitors, none are brown on top or misshapen to indicate they are dead, board visually looks fine.
* Dead board?? It was sold to be as "untested" hence cheap, although from a source that seemed ok
This is a pic of the system rigged up, the crocodile clips are soldered directly to 6 amp wires so not using the normal thin cable in crocodile clips.
Wired up as follows: (numbers are the traces on top, on the side with all the components, alphabetical letters are underside):
1: Gnd (pins 1 and 2 are shared)
3: 5V (pins 3 and 4 are shared)
6: 12v
12: Rgb
13: rgB
14: Gnd (video)
N: rGb
P: C-Sync
Didn't rig up the start, coins, direction or action buttons, or audio; all I wanted was a screen image initially (and not getting it at the moment).
Bottom line is if I can't get this board to work i'll abandon the NeoGeo in my project as i'm not paying about £80 for a replacement board on ebay and then a multicart for another £80 - I don't mind getting a multicart if my current board works, but not to pay double that!
Being the board it is, all the chips are soldered onto the board, the battery is a circular one raised off the board (so not a leaky battery), no traces appear to be broken or damaged on the boards.
So guys, i'd welcome your comments to help me get this board working, if in fact it is able to work. What does the screen image above indicate - faulty board, insufficient amperage, etc?
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