Dead P1 ROMs with weird circle mark on top

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Abelardo

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Hello everyone, haven't been active in the forum but I've been doing some repair work lately and I thought I'd post about it.

So I had a couple Waku Waku 7 MVS carts that didn't boot (went straight to crosshatch), I cleaned them and check for any continuity problems but couldn't find anything, then I noticed this weird circular mark on top of the P1 ROMs:

h1J3zIK.jpg


So I desoldered them and they both read as garbage, is that circular mark indicative of internal burning?

Somebody pointed me at 27C800 EPROM for a suitable replacement so I'll order some, I'll post a followup but it's going to be maybe a month before I get them in the mail :p
 
shadowkn55

shadowkn55

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That's where the memory cells are located and they've burnt out leaving a visible mark.
 
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Abelardo

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daskrabs said:
Talk to Fox1. He'll burn roms for you.
Click to expand...

Thanks, good to know about Fox1, I'll keep it in mind. I've ordered some EPROMs already so I'll try my luck at burning them myself, actually yesterday I ordered some 27C160 because I hadn't realized 27C800 was a better fit, anyways I think the 27C160 EPROMs will work just as well, I just need to burn the data twice and maybe send to ground A19.
 
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Abelardo

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Yesterday I went though my broken MVS carts and found out more P1 roms with the circle of death, a Metal Slug 2 cart that went straight to crosshatch, a MSX that crashed as soon as it booted and Unibios CRC check ROM Region came up as NG, and yet another MSX that doesn't boot at all (it keeps resetting, maybe the P1 shorted internally?). Looks like I'm going to be busy for a while when those EPROMs finally show up in the mail!
 
Neo Alec

Neo Alec

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This is not a common issue with carts. I wonder if these were all perhaps used in the same bad system.
 
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Abelardo

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Neo Alec said:
This is not a common issue with carts. I wonder if these were all perhaps used in the same bad system.
Click to expand...

It could be, I'm sure the MSX carts came from the same lot, it was a lot of non-working MSX carts I purchased from a seller online, the Waku Waku 7 carts I'm unsure if I got them together, but at least one came from a local seller and remember that before testing I opened it and the P1 was like that, at least I am relieved that my system is not the one to blame.
 
NexusX

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I had a RBFF2 cart with the same problem and visual marks. Fox1 made a new one for me and it booted right up once installed.
 
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Abelardo

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NexusX said:
I had a RBFF2 cart with the same problem and visual marks. Fox1 made a new one for me and it booted right up once installed.
Click to expand...

Thanks for the confirmation! I'm hoping for an easy fix like that, just burn the EPROM and install :)
 
Xian Xi

Xian Xi

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Neo Alec said:
This is not a common issue with carts. I wonder if these were all perhaps used in the same bad system.
Click to expand...

It’s common with the Toshiba mask roms. You get either a circle or a brown square in the center if the rom dies, sometimes cracks as well.
 
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Abelardo

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Quick follow up, yesterday I finally got the EPROMs and fixed one of the Metal Slug X carts (the one that crashed and CRC came up as bad), I did use a 27C160 and had to burn the ROM twice but it worked as expected, the other MSX cart has some other issue that seems related to the Altera MAX (I think it shorted internally :confused: ), will be doing the Waku 7 carts and MS2 most likely on Friday, by the way I' going to convert that MS2 cart to Turbo, I don't like it because of the slowdown so I'll check out the patched version :D

Thanks everyone!
 
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