Neo-MVH SLOT1F

iborg

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Hi all,

I've got a Neo Geo MVH 1 slot when powering up shows just a screen of garbage. There's no battery damage and i cant see any damaged traces. Using a logic probe i noticed the CE is low and the OE & WE are high on all work/backup rams, which according to the truth table for the CXK58257AM rams means the outputs are disabled. Would this be causing the board not to boot? If so where else should i be looking to see whats causing this issue.
 
Thanks for your reply. I went over the 6800 with the logic probe and noticed 7 address lines either high or low without any data being transmitted and 3 data lines in the same way. Does this mean the 6800 is faulty?
 
Well.. maybe.. but not conclusively.

The data pins are bidirectional - so as well as the 68000 putting data out on them, the BIOS rom chip (as well as other things) should also be putting data on them. Having 3 silent pins would be quite weird.

Check if the 68000 is getting a clock signal, and if so check the output enable (/OE) pin on the BIOS rom to see if the 68000 is asking it for data.
 
Hi all,

I've got a Neo Geo MVH 1 slot when powering up shows just a screen of garbage.

Did you ever make any headway on this one? What kind of garbage was it? Is it the green screen with seemingly random looking garbage glitches, or something else? Can you post a photo perhaps so we can better see what the offending behavior looks like?
 
I've made a little. Using the logic probe i stuck it against one of the data lines on the sram that wasnt getting any data out while powering on the board. I noticed that for about 1 second or so it had data then went from stopped.

Attached is a picture of what im seeing.
 

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I've made a little. Using the logic probe i stuck it against one of the data lines on the sram that wasnt getting any data out while powering on the board. I noticed that for about 1 second or so it had data then went from stopped.

Attached is a picture of what im seeing.

Is it watchdogging, or just frozen on the garbage? Also, just curious, but how are the hard dips set, and is there currently a battery installed at all?
 
if you give up, I have a one slot that works 100% for sale
comes with a brand new 161 in 1 too for 200 shipped if you want
 
Is it watchdogging, or just frozen on the garbage? Also, just curious, but how are the hard dips set, and is there currently a battery installed at all?

With the standard BIOS rom its installed its a frozen screen of garbage, but the screen seems to change the one below when i use the diag bios and i can see a few flickering bits of garbage. As for the hard dip set there all set to off. I've also got the old Ni-CAD battery. Its not leaking but it will be removed once i get the board working.
 

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