MVS (4 slot) slot 3 and 4 are not working

[Nerdy]

Hello guys i need some help with something

I have been using a 1 slot mvs board for quiet some time now, so i left my 4 slot mvs board stored.

When i took it out to install it on my cab again, i am having some issues

The games that are inserted on slots 3 and 4, dont work.

I have already done some extensive cleaning in the slots, and the games im using play straight away on the other slots and other boards.

already checked for traces and they seem to be fine.

So any clues on what i should be looking for ?

thanks in advance

 

[xsq]

are the pins in the (supposedly) defective slots tight enough to make good solid contact with the cart pcbs? Helped me with another cartridge based system to bend them to the middle a bit...

you need to be very careful about this though - if you think the contacts are fine this is most likely some other issue.

 

[Nerdy]

Well does not seem to be the case, they feel the same way as the other slots. is there any way for me tu fully test or check if the pins may not be tight enough?

 

[RabbitTroop]

Well does not seem to be the case, they feel the same way as the other slots. is there any way for me tu fully test or check if the pins may not be tight enough?

It's pretty hard to do if you're getting nothing. If you were getting errors or a blank screen, I'd say take out all carts except for one in one of these troubled slots, turn on the machine and gently move it to see if you can make a better connection. This helps with games that have sound or graphical issues in certain slots. For instance, one of my slots is a pain in the butt to get things seated correctly. 9 times out of 10 video is fine, but music won't play unless you reseat it a few times.

If you're getting nothing but a cross-hatch, it gets harder to troubleshoot.

 

[mjs256]

The only way to really know if you are making good contact is to check for continuity one pin at a time. Open up the MVS cart and remove the two boards (but keep track of which is which). Insert one board into the proper half of the slot in the correct orientation and then use a multimeter or continuity tester to verify contact between each pin (front and back side) and the slot socket. Remove the one board and put the other board in the other half of the slot and test it the same way. If you verify 100% connectivity for both boards then you know it is a problem with one or more bad traces and/or ICs. Bad traces can be found by testing continuity, but bad ICs require a logic probe or oscilloscope to find. The fact that the problem is only with slots 3 and 4 should help narrow it down. Good luck!

 

[xsq]

here are some other things you might try: 1. clearing the backup ram (before turning your system on, set all hard dips to 1 and let the "Work Ram Test" sit for a minute or two, then turn it off and flip all the DIPs back up)... 2. maybe it's the kind of games - how about combining some earlier games with low meg count? (don't combine "330 mega" and "giga power" carts). You could also try the 6slot method and go from slot to slot (set cart in slot 1, if it works move on to 2, only if that works go on and try to get 3 to work...) 3. Maybe try setting the carts in on slots 3&4 and then slightly pull them up or wiggle them around a bit - they might get a little more/the right contact then... 4. check the voltage (5V).

Are you getting the cross hatch test when you do insert carts into slots 3&4 but not 1&2? Do you get garbled video/sound on slots 3&4 or plain nothingness? If you do have the Unibios, can you read out the carts and do they come up with the correct data?

you might be interested in these threads/posts as well:
1, 2, 3, 4, 5.

 

[Nerdy]

Well i will be checking on all tips on my next day off they were working fine (the slots) before going to storage, but they were already giving a hard time to get the games run without any glitches, sound issues, so my first bet was the contacts being very very dirty (and they were, after i cleaned them with the "credit card" trick)

I will keep you guys posted !

 

[_rm_]

Hi Nerdy,

i assume you have checked the 5v, right? The 4 slot boards require much more power to work fine.
Just a reminder.

 

[Nerdy]

Hey i checked that, the arcade im using the board its the same one i used all my life and it worked fine :P

The only thing that happens if i just plug games into slot 3 or 4 it goes into "test" mode, with the colours, the lines, sound, input, etc

My best bet is the contacts are not good.

 

[xsq]

yeah, guess so. The board doesn't seem to be recognizing the carts in slots 3&4 at all... hopefully one of the tips above helps, what mjs256 wrote should be the next logical step. Other than that I can't give you any more advice... sorry mate. Really hope you get it to work again.

 

[Nerdy]

i think now what might be the reason for the issue.

the board initially was in a vertical position, with the carts hanging on there, due to the weight and gravity, most likelly the pins are bent in a certain shape because of that.

After the clean up i now have the board laying flat on the arcade, so the pins should still be used to the old position and thus not making a propper contact with the carts.

Ps: usually the most used slots were 3 and 4, makes sense being the ones not working right now, 1 and 2 barely had carts in them.

 

[xsq]

vertical mounting is far from ideal - the carts are pretty heavy and there will have been a lot of stress on the slots. If you get slots 3&4 running that way it might just be a temporary solution and you might also be risking the two good ones.

 

[Nerdy]

I know, thats why i stored the 4 slot and just used a normal 1 slot board, but the arcade was used like this for many years before i bought it, so the pins most likelly and "used" to this position.

I will try to bend the pins back to see if it makes propper contact.

 

[chris1]

I have nothing to add it's all been said already..EXCELLENT..

I hope you get the board going.

 

[RabbitTroop]

I know, thats why i stored the 4 slot and just used a normal 1 slot board, but the arcade was used like this for many years before i bought it, so the pins most likelly and "used" to this position.

I will try to bend the pins back to see if it makes propper contact.

Yeah, likely very carefully going in and trying to tighten up those cart pins will help if that's the case. It's worth giving a shot.