6 Slot Neo Geo issues

beef

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Hey Guys,

I recently got a 6-slot neo-geo that I put into a cab that had a 4 slot in it before. The 4 slot machine has always worked fine.

The first issue that I am having is that sometime the audio cuts out. Sometimes completely, sometimes in one speaker or the other. It comes and goes.

I raised the power supply voltage so that it reads 5.0 at the jamma harness, but I don't know if there is any other place I should check volts at.

The second issue, is that the board will sometime reset if you switch it to a slot that does not have a game in it.

I have already removed the battery on the board and didn't notice any broken traces around the battery, but I can look again if need be.

Any advise would be a big help.

Thanks,
Brett
 
1. Best place to take power readings is on the edge connector. Second best place is the back of the pins inside the JAMMA/MVS edge connector.

2. How many +5v lines do you have connected to your harness? I've seen some 6 Slot owners try and run the HOG with only 1~2 +5v lines. Should have at least 3~4 +5v lines.

3. Also make sure your +5v lines are about 5.0v~5.1v. Try not to go over 5.25v. Some chips fry at that level.
 
Thanks.

1. I tested it at the top side of the mvs edge connector (top side) and set it to 5.0 off of that. Is there another edge connector I am not thinking of?

2. I have all of the +5v lines connected on the harness.

3. I will try upping the voltage a little bit more tomorrow.

Thank you for your suggestions.
 
The audio issues are generally cap related. Bad caps can cause the audio level to fluctuate or to come/go as the board heats up.

It's common to have to recap MVS boards.

RJ
 
Well, I capped the 6 slot and now I have several different issues... which makes think I messed something up.

I get audio in hardware test, however it is lighter on the left side than it is on the right. (f I turn up the volume the right side audio (if I turn it close to 50% or more) get really staticy and horrible sounding. The left side audio is consistant but lower than the right.

I am now getting now sound in games, but the they all play just fine.

Anythoughts?
 
Slight update, I don't get any sound in test mode when there are carts in the machine (running the board with dipswitch 1 on). I only get sound when it goes to the hardware test with no carts in the machine.
 
Check your caps: Make sure the correct caps are in the correct spots.

And check your solder joints on the caps: Make sure the joints have good contact with the board.

http://www.arcadecomponents.com/f/Neo_Geo_Cap_Kits.pdf

6SlotCaps.jpg


http://www.boredstu.com/neogeo/hardware/mv6/mv6main.html
 
I found one cap in backwards, changed that around and the issue still persists. After finding the one backwards cap I verified all other caps are in the correct spot in the correct direction.

I tried tracing the route the right audio goes starting from pin 10 on the mvs connector, but I get get stuck trying to figure out what happens once it goes into (since I am going backwards) the ha13001.
 
Well, I capped the 6 slot and now I have several different issues...
I get audio in hardware test, however it is lighter on the left side than it is on the right.
(f I turn up the volume the right side audio (if I turn it close to 50% or more) get really staticy and horrible sounding. The left side audio is consistant but lower than the right. I am now getting now sound in games, but the they all play just fine ...

... I don't get any sound in test mode when there are carts in the machine... I only get sound when it goes to the hardware test with no carts in the machine...

I found one cap in backwards, changed that around and the issue still persists ... I verified all other caps are in the correct spot in the correct direction ...

Sometimes Cart. arangements can cause the MULTI Slot boards to act odd.

So, remove all the carts from the board. Start the game board up in TEST MODE (DS1 down). Check the audio--Left, Right, Center. Listen for Test Sounds. If you hear Test Sounds from the SPEAKERS, then insert Headphones in to the HEADPHONE JACK and test the audio again. If you hear test still hear sounds, then, power down the board and find a couple of cheap and easy to repalce carts that work.

Next, put one cart. on the game board in Slot #1. Leave the other 5 Slots empty. Start the game board on in PLAY MODE (DS1 up). Listen for game sounds. If you hear none from the SPEAKERS, then put the Headphones in the HEADPHONE JACK and listen for game sounds.

If you hear game sounds from either the SPEAKERS or the HEADPONE JACK, power down the board and add another cart. to the board, like Slot #2. But if you do not hear any game sounds from either the SPEAKERS or the HEADPHONE JACK, then power down the board and move that cart. to the next Slot on the board (Slot #2) and repeat.

The general idea is to find out which Slots on the board have game sounds from either the SPEAKERS or the HEADPHONE JACKS and which ones do not. So, if a Slot has sound, then leave a cart in it. And if it does not, then move it.
 
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I tried that and it appears that slot 1 is the only that has no audio. Even with 5 other working carts. However, at no time did I get audio out of the head phone jacks. I verified the head phones worked with my computer before I plugged them in, so I don't believe it is the head phones.

The games show the same issues as the sound test in which the right side audio is much louder than the left. That I feel that is the most important issue. I can try to diagnose slot one after I get the general system audio working. Interesting note, if I run the hardware test without the top board plugged in, I get audio. If I plug in the top board with no carts in and run the hardware test i get no sound. So I believe the audio issue on slot 1 is related to something on the top board (that's at least a place to start looking).

I know my solder jobs where better than my desolder jobs, I am wondering if I created a short in the board when I was removing the caps. But, just to be sure, I am going to go over all the caps today and touch up the solder to see if that has any effect.

Any other ideas of places to check, or any resources about the flow of the right channel audio (so I can trace in on the board) would be a great help.

Thanks you for all your help so far.
 
Time to start checking traces. I found a bad trace under the black protective mat on one board which caused one slot out of 6 not to play a game and had horrible sound coming from it when a cart was placed in that slot.
 
So, I believe I tested the headphone support incorrectly. Apparently JP3 is the headphone (which comes off the board as a 4 prong plug). And JP4 and 5 are something else. I just got in a memory card reader (today actually). I will try to get that plugged up at some point in time and re-test the headphone support.

darthi8nt, which pad? The one on the top board? or one of the ones on the bottom board. Thanks.
 
So, using my friend's oscilloscope we found something interesting. The right speaker audio appears to be shifted up 5v compaired to the left audio.

Problem appears to be around the last cap on the right speaker audio side of the board. Checking both the left speaker and the right speaker going into the last cap (for each specified side) the sin wave looks the same. Coming off of the caps the left side shifts down 5v, but the right side stays the same.

We removed the cap on the right side, and no sign goes to the right speaker. So, there is no short between the holes for that cap. I tried replacing the cap with a different one, and it did the same thing.

It appears that there may be an issue around that cap on the board, but I don't know what. I could try another cap, to see if I happened to get 2 bad ones.

Anythoughts?
 
The 470uf cap between the amp chip and the JAMMA edge is a DC blocking cap and should block the DC component from the speaker.
 
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