What can make a whole section of roms go bad?

ebo0763

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The connections are cleaned with DeOxit and it still shows whole sections of roms being bad... and voltage is +5.21V. Is there something else that would affect without necerely being bad roms?

 
shorted/touching pins on the solder side or maybe a chip put in wrong.

you tested that 5v at a chip right not at the power supply/edge connector (that's the proper location not that it is the cause of your issue).
 
So one chip put in wrong could affect all others?

Yup

Exacly 5V? which pin?

i tend to shoot for 5.13v


Note where the KEY notch is don't probe the wrong legs.

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Picture courtesy of Mecha
 

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MK-II boards came in two eprom configurations (for graphic eproms)

12 x 8Mb eproms
or
24 x 4Mb eproms

Since the main board only has 16 sockets for graphic eproms (UG13-24, UJ13-24),
an AUX board was used to accommodate the 8 extra 4Mb eproms.

So some MK-II are single boards with 12 x 8Mb eproms,
while others are dual-boards with 24 x 4Mb eproms.

Since the data is the same for both eprom configurations,
I've always assumed that there must be some jumper or DIP setting on the main board
that would indicate what eprom configuration is used.

... although I've never found info on that.
(... anyone who knows this would be most welcomed to comment... )

In your case , since it appears to only be the graphic eproms that are bad,
I strongly suspect that your board is somehow set to the 4Mb eprom setting
(...because it is showing the AUX board on boot-up )
when perhaps it should be set to the 4Mb eprom setting.
(...do you have an AUX board ? )

But like I said, this is merely my best guess
based on info I "believe" to be good, but never really validated...

I really can't see any other explanation that would only affect the graphic eproms only.

The game (code) roms at UJ12 and UG12 are good,
so a short on the eprom bus would appear unlikely...

Good luck...

Steph
 
Since the data is the same for both eprom configurations,
I've always assumed that there must be some jumper or DIP setting on the main board
that would indicate what eprom configuration is used.

... although I've never found info on that.
(... anyone who knows this would be most welcomed to comment... )

In your case , since it appears to only be the graphic eproms that are bad,
I strongly suspect that your board is somehow set to the 4Mb eprom setting
(...because it is showing the AUX board on boot-up )
when perhaps it should be set to the 4Mb eprom setting.
(...do you have an AUX board ? )

But like I said, this is merely my best guess
based on info I "believe" to be good, but never really validated...

I really can't see any other explanation that would only affect the graphic eproms only.

The game (code) roms at UJ12 and UG12 are good,
so a short on the eprom bus would appear unlikely...

Good luck...

Steph


i forgot about that, there is a dip switch for that i use to know what it was but can't find it in the damn instructions right now, i know it's listed in the actual test menu tho.
 
Bank UJ1 (1),dip switch 8 should be set to OFF for 2 circuit board version (aka 4mb chips)


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So those are two places where I can find the 5V or do I put the black and red of my multimeter on those two pins?

black on one pin red on the other pin
 

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Update!

The game works! All roms are good! But something is flimsy...

You make all the roms work or not work by touching the ds banks (without switching the buttons). I mean you just kind of push it a bit and the game will work. Do it again and it'll stop reading the roms.

I noticed that UJ1 #8 skip the boot board test. And #7 I couldn't figure it out.

My guess is that UJ1 #7 is for switching between 4Mb and 8Mb. And also the switch must be damaged somehow and it sometimes gets in contact and sometimes not. Any thoughts on this?

FYI, I have version 2.0 with a daughter board.

 
Your DIP screenshot is different than the one on the previous post by Broodwich.

His has options for Dip #7 (power-up test)
and #8 ( 4M / 8M setting) whereas yours doesn't.

You said you had v2.0 which I suspect explains why.

V2.0 probably only supported the 4Mb eproms,
so this feature (DIP option #8) was not needed .

I'm guessing that later versions ( v3.0+ ? ) had the option of 8Mb roms,
so the DIP option #8 was used.

---

And indeed, if the game is flakey when touching the dipswitch banks,
I'm guessing that's your problem (ie. The 4M/8M settings get tripped )

I'd consider replacing it/them.

Good Luck.
Steph
 
interesting sounds like your dip bank or the solder joints behind it might be bad?(just like steph said) regardless glad you got it running.
 
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Steph,

you've always assumed that there must be some jumper or DIP setting on the main board
that would indicate what eprom configuration is used.

Correct - your 4 jumpers (0 ohm) are located above EPROM chips UJ14 & UG14. J28 to J27 J25 to J24, etc. These are used to set the board to single layer or that with the memory expansion board. That's not all you need though to convert the board!

MK-II boards came in two eprom configurations (for graphic eproms)

12 x 8Mb eproms
or
24 x 4Mb eproms

Since the main board only has 16 sockets for graphic eproms (UG13-24, UJ13-24),
an AUX board was used to accommodate the 8 extra 4Mb eproms.

So some MK-II are single boards with 12 x 8Mb eproms,
while others are dual-boards with 24 x 4Mb eproms.

Since the data is the same for both eprom configurations,
I've always assumed that there must be some jumper or DIP setting on the main board
that would indicate what eprom configuration is used.

... although I've never found info on that.
(... anyone who knows this would be most welcomed to comment... )

In your case , since it appears to only be the graphic eproms that are bad,
I strongly suspect that your board is somehow set to the 4Mb eprom setting
(...because it is showing the AUX board on boot-up )
when perhaps it should be set to the 4Mb eprom setting.
(...do you have an AUX board ? )

But like I said, this is merely my best guess
based on info I "believe" to be good, but never really validated...

I really can't see any other explanation that would only affect the graphic eproms only.

The game (code) roms at UJ12 and UG12 are good,
so a short on the eprom bus would appear unlikely...

Good luck...

Steph
 
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