MVS2F doesn't boots

akirasan · May 14, 2016

Hi,
I've recovered a MVS2F from an old arcade and the owner did not guaranteed me the right function, so I decided to follow the manual consolización JNX on a MVS2F. I've put a power source of a cellphone that works on 5V, the battery mod and SCART video output as explained in the tutorial (taking RGB signals, sync, 5V and GND only).

The machine turns on properly, the red LED is on but screen shows what you see in the picture:

What's happening here? It has a brand new unibios 3.2 , so I discard a problem with the BIOS concerning the chip. It not shows anything but this.

Thanks in advance!

bustedstr8 · May 14, 2016

The MVS probably draws waaaaaaaay more than that PSU can handle.

akirasan · May 14, 2016

The PSU is 5V and 3A, I thought that were enough... What kind of PSU the MVS needs then? I would like to put that inside so I won't need any external PSU, connecting an 8 wire like PSX or PS2.
Here is how I connected:

akirasan · May 14, 2016

Sorry about the tiny pics!

mikejmoffitt · May 14, 2016

I have my doubts that it can actually deliver 3A. I would seek out a better, beefier power supply at least for testing. A PC power supply will do well.

On another note, your board is missing the 7805 voltage regulator in the audio section. If you want sound, you're going to have to get 5V to that section at some point...

aha2940 · May 14, 2016

mikejmoffitt said:
On another note, your board is missing the 7805 voltage regulator in the audio section. If you want sound, you're going to have to get 5V to that section at some point...

I believe removing the 7805 is part of the consolization process, since you usually only feed +5V to a CMVS: http://www.jamma-nation-x.com/jammax/files/cmvsmv2f.pdf

Regards.

akirasan · May 14, 2016

mikejmoffitt said:
I have my doubts that it can actually deliver 3A. I would seek out a better, beefier power supply at least for testing. A PC power supply will do well.

On another note, your board is missing the 7805 voltage regulator in the audio section. If you want sound, you're going to have to get 5V to that section at some point...

Aha2940 is right, I removed it for consolization.
With 5V/3A the board would work? Maybe I could find a better PSU, since I don't have any PC ps and I don't want to buy one for testing (if I can avoid it lol).

aha2940 · May 14, 2016

akirasan said:
With 5V/3A the board would work? Maybe I could find a better PSU, since I don't have any PC ps and I don't want to buy one for testing (if I can avoid it lol).

With a real PSU of 5V 3A the MV2F should work fine in my experience.

Xian Xi · May 14, 2016

I don't think it's the power supply but rather the choice of wire. For power, use something at least 22awg, that wire in the pic is most likely 28awg, I doubt it can even carry 1A. But at the same time, you should always confirm you have a working PCB before you consolize it so you know what the problem is either the board or the consolization.

akirasan · May 15, 2016

Xian Xi said:
I don't think it's the power supply but rather the choice of wire. For power, use something at least 22awg, that wire in the pic is most likely 28awg, I doubt it can even carry 1A. But at the same time, you should always confirm you have a working PCB before you consolize it so you know what the problem is either the board or the consolization.

Amazing eye! you're right, it's 28awg, from a IDE HDD.
The board might have some problems, I tried it with a supergun a while ago and it didn't work, but I don't have any supergun right now. I thought to arrive at the same point I did with the supergun and then repair it from there.
Anyways, I will try with a better wire. Many thanks!

Xian Xi · May 16, 2016

akirasan said:
Amazing eye! you're right, it's 28awg, from a IDE HDD.
The board might have some problems, I tried it with a supergun a while ago and it didn't work, but I don't have any supergun right now. I thought to arrive at the same point I did with the supergun and then repair it from there.
Anyways, I will try with a better wire. Many thanks!

If it's a known non-working board, try busting out a logic probe and check for activity on the 68k. If it's dead then that could be the problem. The fact that there's something on the screen means at least the clock is working.

akirasan · Jun 14, 2016

After buying a brand new power supply with 5V and 10A, the MVS has revived! I'm so happy to see it working, but it has graphical glitches only in game graphics, but the games's HUD and texts works well.
I've uploaded a video to show you the problem:

Where should I start to look?
Thanks!

akirasan · Jun 14, 2016

And the BIOS shows this:

HeavyMachineGoob · Jun 14, 2016

Looks like the upper VRAM has died.

akirasan · Jun 14, 2016

You mean the CXK5814P-35L? How can I know if it's dead or only bad traces?

Xian Xi · Jun 14, 2016

akirasan said:
You mean the CXK5814P-35L? How can I know if it's dead or only bad traces?

Check the trace on pin 11 on the upper ram.

akirasan · Jun 14, 2016

The pin 11 seems to be good, the output is:
Addr 00008000
wr 5555
re 0055

Is there any table with all the traces from upper and lower ram? The only way I have is checking one by one.

Xian Xi · Jun 14, 2016

akirasan said:
The pin 11 seems to be good, the output is:
Addr 00008000
wr 5555
re 0055

Is there any table with all the traces from upper and lower ram? The only way I have is checking one by one.

The error changed?

Xian Xi · Jun 14, 2016

Also the upper ram is the one on the bottom not the top. Upper indicates higher bits not physical location.

akirasan · Jun 15, 2016

Depends on boot, the error changes. All of these are from screen ram, maybe there are many traces broken :crying:

I understand upper ram is the left 58527 from there:

Am I right?
As you see, many traces may be damaged due corrosion, I changed the battery but I have to do a super clean in that area.

Xian Xi · Jun 15, 2016

Check the one on the right, pin 15 looks like it may be shorted to pin 16.

akirasan · Jun 15, 2016

I've checked and everything seems fine (no shorts), I've cleaned the board seriously but I can't see any problem with a fast sight, as you can see in the images:

Rear back on the vram's:

Front:

Where do I continue looking for?

aha2940 · Jun 15, 2016

akirasan said:
I've checked and everything seems fine (no shorts), I've cleaned the board seriously but I can't see any problem with a fast sight, as you can see in the images:

Rear back on the vram's:

Front:

Where do I continue looking for?

Nice cleaning. How did you do it? Also, the next step if the traces are all OK, would be the memory chips themselves.

akirasan · Jun 15, 2016

Thanks! I put it under the shower, best way to clean anything! :lolz:

Which memory chips you mean? SP1 or SFIX maybe?

aha2940 · Jun 15, 2016

akirasan said:
Which memory chips you mean? SP1 or SFIX maybe?

The memory ones, those are the ones referenced in the error. They are usually sony brand in those boards. Not sure where they are located, though, maybe they are the ones you are looking at in the picture.

MVS2F doesn't boots

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