Question about Mario Bros. Pcb -5v function

TheEnglishTear

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Hello, I have a Mario bros pcb that seems to work with sound and controls, but no character sprites or title screen (Mario title is missing). My question is, I'm testing on a cab that doesn't have -5v which is required by the board. So, is the missing voltage(-5v) the reason for no characters, and what does the -5v function?

Thanks
 
The object-RAMs MB7074 are ECL-chips wich need positive and negative power supply.

So it's more than possible you don't have sprites w/o the -5V . ;)
 
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that all sounds very fancy, and clearly you know what you're doing... could he just find another switching power supply that has a -5v output? assuming he is using a proper harness etc. I made up a test harness for DK boards (with rainbow cable installed) to bench test on a switching power supply outside of cabinets, my understanding is that the DK/MB generation of boards all used the same pinout. If he has the proper harness, sourcing another switching power suppy with -5v should do the trick, no?
 
that all sounds very fancy, and clearly you know what you're doing... could he just find another switching power supply that has a -5v output? assuming he is using a proper harness etc. I made up a test harness for DK boards (with rainbow cable installed) to bench test on a switching power supply outside of cabinets, my understanding is that the DK/MB generation of boards all used the same pinout. If he has the proper harness, sourcing another switching power suppy with -5v should do the trick, no?

^^ this is what crossed my mind. However, I've heard using two power supplies in one game is a no no
 
Hello, I have a Mario bros pcb that seems to work with sound and controls, but no character sprites or title screen (Mario title is missing). My question is, I'm testing on a cab that doesn't have -5v which is required by the board. So, is the missing voltage(-5v) the reason for no characters, and what does the -5v function?

Thanks

I'm not sure my Donkey Kong ECL RAM eliminator boards fit on Mario Bros, but if so, that's eliminate the need for -5V...
 
my intention was for you to swap out the power supply, not run two.. not sure exactly what the setup is you are testing it in. is the harness wires for the -5v? is it a full Nintendo harness? idk, lots of questions
 
my intention was for you to swap out the power supply, not run two.. not sure exactly what the setup is you are testing it in. is the harness wires for the -5v? is it a full Nintendo harness? idk, lots of questions

I'm testing in a Popeye cab. I believe all voltages are there, just not -5v
 
Thanks so much for this thread. I was testing a newly acquired Mario Bros in my fully functional Popeye cab and couldn't figure out why i wasn't getting any sprites. Thanks!
 
Thanks so much for this thread. I was testing a newly acquired Mario Bros in my fully functional Popeye cab and couldn't figure out why i wasn't getting any sprites. Thanks!
No prob, I sold my Pcb years ago. Turns out once I tested it with -5v and +5v the game was normal. I should've updated this post with that info
 
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