Marble Madness TTL bipolar prom ok ? odd part number

cwilbar

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Marble Madness TTL bipolar prom ok ? odd part number

OK... so I'm having difficulty resolving this one....

I have a TTL Marble Madness cartridge, I have not tested it yet.

However, I read the bipolar PROMs with my programmer and have been trying to determine if they are ok.

I know one should be, 136033-119 has the same SHA1 sum as in the mame source.
However I don't have a 136033-118. Instead I have a 136033-155.

I find no mention of that # in a google search.

The sha1 sum is not that of 136-118.

Here is a comparison of byte values to the -118 from mame:

$ od -t x1 033155_bad.bin
0000000 e8 e9 ea eb ec ed ee ef d8 d9 da db dc dd de df
*
0000100 f0 f0 f0 f0 f0 f0 f0 f0 f0 f0 f0 f0 f0 f0 f0 f0
*
0000400 b8 b9 ba bb bc bd be bf b8 b9 ba bb bc bd be bf
*
0000500 f0 f0 f0 f0 f0 f0 f0 f0 f0 f0 f0 f0 f0 f0 f0 f0
*
0001000

$ od -t x1 tmp/136033.118
0000000 e0 e1 e2 e3 e4 e5 e6 e7 e8 e9 ea eb ec ed ee ef
*
0000100 f0 f0 f0 f0 f0 f0 f0 f0 f0 f0 f0 f0 f0 f0 f0 f0
*
0000400 d8 d9 da db dc dd de df d8 d9 da db dc dd de df
*
0000500 f0 f0 f0 f0 f0 f0 f0 f0 f0 f0 f0 f0 f0 f0 f0 f0
*

the first row and 3rd row differ, the 2nd and 4th row are all f0 in both images.
This leads me to think this data may be ok for a 136033-155, but WTF is a 136033-155 !?

Hoping a System 1 guru can shed some light on this one. I don't want to burn a -118 and use up a blank prom if the 155 is ok, and correct to use (it is in location 6A (TTL PCB, not LSI).

I also have another MM board (LSI) version that had no EPROMs or bipolar proms. I burned EPROMS and bipolar PROMS using the images from the LSI cart romset of MAME.
I haven't tested this one either yet.
 
Looking at the schematics and the data, it's pretty obvious what's going on.

-118 is the decoder for 27256s

-155 is the decoder for 27128s

The rest is left as an exercise to the reader....
 
Marble Madness TTL bipolar prom ok ? odd part number

The 155 is correct. I have one in my MM TTL card working just fine. Assuming of course that your 155 is not bad. I recently dumped mine for someone else and can send you the file if that helps. PM me.
 
Bah.... answers in the schematics, and nothing to be found by trolling google....

google fail :)

Hopefully I'll have another member's dump of that prom soon and I can compare it to mine to make sure it is sane.

Still can't figure out why I'm finding so many bad PROMs on system 1 carts (at least 2 out of the 7 carts I have).
 
I already told you the data is correct and why it's different from the other PROM. All you're going to learn from getting someone else's data is that it doesn't match because you didn't dump your PROM correctly.
 
You did Hudson ? I guess I couldn't read between your lines....

"Looking at the schematics and the data, it's pretty obvious what's going on.

-118 is the decoder for 27256s

-155 is the decoder for 27128s

The rest is left as an exercise to the reader.... "

This does NOT say that the contents are fine.

It does explain the situation, but does NOTHING to validate the content.

I did receive a dump and the contents are correct.

Thank you everyone (even Hudson for his explanation, but not for the rest :) ).
 
You did Hudson ? I guess I couldn't read between your lines....

"Looking at the schematics and the data, it's pretty obvious what's going on.

-118 is the decoder for 27256s

-155 is the decoder for 27128s

The rest is left as an exercise to the reader.... "

This does NOT say that the contents are fine.

It does explain the situation, but does NOTHING to validate the content.

I did receive a dump and the contents are correct.

Thank you everyone (even Hudson for his explanation, but not for the rest :) ).


Hint:
If the data were garbage it won't be an address decoder for 27128s.

If you took the time understood the very simple circuit, you wouldn't need to ask these questions.
 
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