4 Slot MVS troubles......

Robert Wallace

Robert Wallace

Sieger's Squire
Joined
Jul 27, 2002
Posts
812
I hook it up to my Supergun and put in some games. The only thing that comes up is the grid screen.

I took it apart to have a look around for bad soldering,caps,any dammage.... and found nothing.
This 4 Slot board looks PERFECT!

I tried all of the dip switches..... Does anyone have any ideas?

The caps all look good, infact this board looks pretty NEW.

*** I got this from Ebay, It was a given that the board was Defective ***

<img src="graemlins/help.gif" border="0" alt="[Help]" />
 
ttooddddyy

ttooddddyy

PNG FTW,
Joined
Nov 29, 2001
Posts
8,335
Clean the cart contacts and board sockets. The cross hatch comes up if there are no carts inserted, if the contacts are dirty the same thing can occur.

Details here <a href="http://www.hardmvs.com/html/projects.htm" target="_blank">http://www.hardmvs.com/html/projects.htm</a>
 
Robert Wallace

Robert Wallace

Sieger's Squire
Joined
Jul 27, 2002
Posts
812
I cleaned the slots...tried that and still the same, just a grid screen.

The slots were pretty clean to begin with. I just noticed that this one is smaller that my other 4 Slot board.

I wonder what could be wrong with this one...... The other board I got works Perfect, it was supposed to be Defective also. I cleaned the slots and Jamma Fingerboard and it has always worked for me.

hmmmmm.........(scratches his head)..... <img src="graemlins/spock.gif" border="0" alt="[Spock]" />
 
L

LastResort

King's Dry Cleaner
Joined
Dec 13, 2000
Posts
392
Probably your power supply of your super gun doesn't deliver enough power for your 4-slot.
Recommended are a one slot or 2-slot for use with superguns. Look at the output power of your supergun, my guess it's insufficient for the 4-slot.
Or try one of the other slots to plug the game in, sometimes the MVS board doesn't detect a game inserted in a certain order.


LastResort

[ October 28, 2002: Message edited by: LastResort ]</p>
 
ttooddddyy

ttooddddyy

PNG FTW,
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What I have found with a low 5 volts at the edge connect the board will not boot to the cross hatch pattern, it gives a green raster with some screwd up gfx.
 
MKL

MKL

Basara's Blade Keeper
20 Year Member
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Originally posted by LastResort:
<strong>Probably your power supply of your super gun doesn't deliver enough power for your 4-slot.
Recommended are a one slot or 2-slot for use with superguns. Look at the output power of your supergun, my guess it's insufficient for the 4-slot.</strong><hr></blockquote>

The question is: how much current will a 4-slot draw? 1-slot's are about 3-5A on +5v and 1-2A on +12v, so for those a 50W PSU is enough (5x5 + 2x12 = 49).
Now, let's assume a 4-slot draws 10A on +5v and 2A on +12V (I think it's less actually). This means a 100W PSU is more than enough (10x5 + 2x12 = 74).
Arcade PSU's are generally 15A on +5v and 2A on +12v (and 0.5A on -5v), i.e. 100W. The upshot is that to power a 4-slot alone the average arcade psu is enough. Sometimes I hear such claims as "you need a 200W or 300W psu", but this is just BS.
Note that 4-slot dedicated cabs used a 150W psu (16A/+5v, 5A/+12V) but in a cab there are other things that draw power beside the PCB and anyway that's more than enough. So the suggestion to get a more powerful PSU can be ignored.

The problem on the other hand may well be the one suggested by toddy, i.e. low +5v. Unless you have the +5V knob completely turned off, the cause of this is likely to be bad wiring. With bad wiring I mean overlong wires (I've seen sg's with 6' harness and hence 6' power wires), too thin wires (less than 18AWG/0.75mm is bad) and too few wires (sometimes just one +5v wire is used).

I've recently built a sg and have used the 150W psu of the MVS dedicated cabs. I've used 4 +5v 18AWG wires (the psu had only 3 so I added another) and the run from the PSU to the harness is 3-4". The result? I never had to tweak the knob, because it's always +5v even, at the edge connector.
Click to expand...
 
ttooddddyy

ttooddddyy

PNG FTW,
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Dont know about the 4 slots but I know the 6 slots draw about 5 amps ( I went through the excercise recently) the unused carts are switched out of circuit so there is no reason why they should draw more that a single slot imho. Tested it with all slots occupied and then just one, the draw is the same.
 
MKL

MKL

Basara's Blade Keeper
20 Year Member
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Originally posted by ttooddddyy:
<strong>Dont know about the 4 slots but I know the 6 slots draw about 5 amps</strong><hr></blockquote>

What I suspected...(I assumed 10A just for the sake of argument).

This shows that multi-slots need about 50W (5x5 + 2x12 = 49)... and any arcade psu is capable of that (going with 200-300W psu's is plain silly)...

[ October 28, 2002: Message edited by: MKL ]</p>
Click to expand...
 
L

LastResort

King's Dry Cleaner
Joined
Dec 13, 2000
Posts
392
Hmm what i meant was if the power supply delivers exactly +5V at the edge connector, A bit more is allowed ,example: 5.1V, 5.2V , but most motherboards or pcb's get into trouble when you go down in voltage. Might be the same here.
Or it's just the order the carts are placed in the 4-slot, seen the same thing happen with some 6-slots.

LastResort
 
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