27C322 Eng Rom to Japanese Chrono Trigger Failed

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your_sunset
Posts: 4
Joined: Tue Mar 14, 2023 10:08 am

27C322 Eng Rom to Japanese Chrono Trigger Failed

Post by your_sunset »

Hello, everybody
Recently I tried to do conversion of my Japanese Chrono Trigger with the support of 27C322 and two multiplexers which I bought from a person who makes repros and I assume everything was written fine.
I tried to follow this scheme by Mousebite Labs which he used for making an adapter
изображение_2023-03-14_171313321.png
изображение_2023-03-14_171404368.png
But after soldering it turned out that game does not work, it boots, but fails each time differently, sometimes after a minute, sometimes after five minutes. Firstly artifacts appear, then game freezes and gets stuck. Also it doesn't boot again right after that but if cartridge lays for a while without powering, only then it can boot again.

Maybe someone can kindly help with the issue? I've seen someone put OE signal to MAD chip, but it isn't described in scheme. I would appreciate any help
изображение_2023-03-14_171743558.png
Markfrizb
Posts: 607
Joined: Sun Dec 02, 2012 8:17 am
Location: East Texas

Re: 27C322 Eng Rom to Japanese Chrono Trigger Failed

Post by Markfrizb »

I think you need to connect the chip enable lines to the rom.
your_sunset
Posts: 4
Joined: Tue Mar 14, 2023 10:08 am

Re: 27C322 Eng Rom to Japanese Chrono Trigger Failed

Post by your_sunset »

Markfrizb wrote: Tue Mar 14, 2023 3:56 pm I think you need to connect the chip enable lines to the rom.
Could you please tell to which ROM pin do I need to connect the line?
gorgyrip
Posts: 58
Joined: Tue Jan 11, 2011 4:41 am

Re: 27C322 Eng Rom to Japanese Chrono Trigger Failed

Post by gorgyrip »

27c322 pin 11 to maskrom 24 (assuming it uses 36pins)
you have that pin grounded in your schematic.
Markfrizb
Posts: 607
Joined: Sun Dec 02, 2012 8:17 am
Location: East Texas

Re: 27C322 Eng Rom to Japanese Chrono Trigger Failed

Post by Markfrizb »

your_sunset wrote: Thu Mar 16, 2023 7:06 am
Markfrizb wrote: Tue Mar 14, 2023 3:56 pm I think you need to connect the chip enable lines to the rom.
Could you please tell to which ROM pin do I need to connect the line?
Ultimately, the multiplexer chips /enable is what needs to be controlled. Turning the rom “off” won’t really help if the multiplexers are still driving. So really, the rom can be enabled all the time like your schematic shows because the signals won’t get through the mux’s if they are controlled correctly
Are you hand wiring this?

Drawing that blue circle around the mask rom makes it difficult to actually see where you connected some of the lines. Not helpful. You can just reference the “mask rom” and we would understand, no circle needed. Lastly, the mask rom /CE (pin 24) should probably go to the 27c322 rom /CE. The maskrom /OE (pin 33) probably the mux’s enable pin. It’s hard to tell but that may be the way you have it already.

Edit: according to the mouse labs chart, it said to connect the /CE as I mentioned
E2BB502F-8BAB-4531-A05F-1AFB29627733.jpeg
your_sunset
Posts: 4
Joined: Tue Mar 14, 2023 10:08 am

Re: 27C322 Eng Rom to Japanese Chrono Trigger Failed

Post by your_sunset »

gorgyrip wrote: Thu Mar 16, 2023 10:59 am 27c322 pin 11 to maskrom 24 (assuming it uses 36pins)
you have that pin grounded in your schematic.
Thanks for your advice, unfortunately, works with the same behaviour
your_sunset
Posts: 4
Joined: Tue Mar 14, 2023 10:08 am

Re: 27C322 Eng Rom to Japanese Chrono Trigger Failed

Post by your_sunset »

Image
Markfrizb wrote: Thu Mar 16, 2023 2:20 pm
your_sunset wrote: Thu Mar 16, 2023 7:06 am
Markfrizb wrote: Tue Mar 14, 2023 3:56 pm I think you need to connect the chip enable lines to the rom.
Could you please tell to which ROM pin do I need to connect the line?
Ultimately, the multiplexer chips /enable is what needs to be controlled. Turning the rom “off” won’t really help if the multiplexers are still driving. So really, the rom can be enabled all the time like your schematic shows because the signals won’t get through the mux’s if they are controlled correctly
Are you hand wiring this?

Drawing that blue circle around the mask rom makes it difficult to actually see where you connected some of the lines. Not helpful. You can just reference the “mask rom” and we would understand, no circle needed. Lastly, the mask rom /CE (pin 24) should probably go to the 27c322 rom /CE. The maskrom /OE (pin 33) probably the mux’s enable pin. It’s hard to tell but that may be the way you have it already.

Edit: according to the mouse labs chart, it said to connect the /CE as I mentioned

E2BB502F-8BAB-4531-A05F-1AFB29627733.jpeg
Here's the schematic I used when soldering
изображение_2023-03-24_203310105.png
Yes, this is handwired
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