I recently extracted all my PCBs from my parent's garage. These had been sat in cold conditions since the 1990s and not used in years.
Surprisingly, everything I tested worked. Apart from my Konami TMNT which had corruption to the graphics. The sprites rendered fine in isolation, but the tiled graphics clearly had major problems.
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhp6lqRKGmdgBfiMymFljb6tBfo8RoNpV_pmnVNYrHXihe1DXWnjlEPdyzHn7xAs3sik1q3JNqLDnw7NpGYBAdMRbHtZ2i7u7HYwZxMU2Bk-EqeEtLPz3KHR8FXHR7HBJgJ4Oi6/s320/20151003_142949_1.jpg)
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjwNxyhOj0Ob9I4Q4lvaMVbz_aPcnyLzgCzyQIGQ2p9Kn_BZ2jAQFe9VoXRDy6qq2PMquX9WjLb6hG9w0xwLeW9D6VE9xn_yG_EJbGr2txKlN3wnsF6WrjjDCfrI30CyJKZYzbz/s320/20151003_142920.jpg)
The game ran fine.
The sound plays.
The RAM/ROM check passed.
The Mask ROM check failed. This required setting a DIP switch to test.
Unfortunately, the Mask ROM test screen was so garbled it was unreadable and I inferred the wrong Mask ROM was bad! In the end, I swapped out two ROMs rather than one. For reference the screen looks like this (not my picture!)
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgHfcLkH896BpqJ-KEeOHTMQlIZOI9EaeNUDl8UdQ8HrqvaUh2P23HcDC-l_PaLg9z3OGmxdPT0vkLr-8qzoJNtnbPOHJgTNEQlTpRz3-TkBmEu-pm1kql_3QThcEDXLFaBdctM/s400/DSCN7113-1.jpg)
After desoldering the Mask ROMs, I used 27c400 EPROMs as replacements.
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjfQeIJKKqpwWFrYwyhOAXR3NisgKfU1hYVB2LeBOG1l9gp9tT3UeTbTnsrAkYa_DxV2ljxT65emfS1VWD8RiIvM0gnFhIBDlL6Rio_Q-JSZcNilh8wWKEb-vpttFb7dgQ6-VHr/s400/tmntrepair2.jpg)
And everything now works. Turtle Power!
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgRr_1uDATrG6vbHahPJ2r9c-bUylD8BQlAVKwIrgYYqHTQwde0YXBPklu4eVepaHQUXGP_T0Po_2U_yWGwyaU1ifyqKPAQfEShAA0g-2dydtSCkNVXE48xbzW1K1xDiBtmQa_F/s400/tmntrepair1.jpg)
Surprisingly, everything I tested worked. Apart from my Konami TMNT which had corruption to the graphics. The sprites rendered fine in isolation, but the tiled graphics clearly had major problems.
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhp6lqRKGmdgBfiMymFljb6tBfo8RoNpV_pmnVNYrHXihe1DXWnjlEPdyzHn7xAs3sik1q3JNqLDnw7NpGYBAdMRbHtZ2i7u7HYwZxMU2Bk-EqeEtLPz3KHR8FXHR7HBJgJ4Oi6/s320/20151003_142949_1.jpg)
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjwNxyhOj0Ob9I4Q4lvaMVbz_aPcnyLzgCzyQIGQ2p9Kn_BZ2jAQFe9VoXRDy6qq2PMquX9WjLb6hG9w0xwLeW9D6VE9xn_yG_EJbGr2txKlN3wnsF6WrjjDCfrI30CyJKZYzbz/s320/20151003_142920.jpg)
The game ran fine.
The sound plays.
The RAM/ROM check passed.
The Mask ROM check failed. This required setting a DIP switch to test.
Unfortunately, the Mask ROM test screen was so garbled it was unreadable and I inferred the wrong Mask ROM was bad! In the end, I swapped out two ROMs rather than one. For reference the screen looks like this (not my picture!)
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgHfcLkH896BpqJ-KEeOHTMQlIZOI9EaeNUDl8UdQ8HrqvaUh2P23HcDC-l_PaLg9z3OGmxdPT0vkLr-8qzoJNtnbPOHJgTNEQlTpRz3-TkBmEu-pm1kql_3QThcEDXLFaBdctM/s400/DSCN7113-1.jpg)
After desoldering the Mask ROMs, I used 27c400 EPROMs as replacements.
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjfQeIJKKqpwWFrYwyhOAXR3NisgKfU1hYVB2LeBOG1l9gp9tT3UeTbTnsrAkYa_DxV2ljxT65emfS1VWD8RiIvM0gnFhIBDlL6Rio_Q-JSZcNilh8wWKEb-vpttFb7dgQ6-VHr/s400/tmntrepair2.jpg)
And everything now works. Turtle Power!
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgRr_1uDATrG6vbHahPJ2r9c-bUylD8BQlAVKwIrgYYqHTQwde0YXBPklu4eVepaHQUXGP_T0Po_2U_yWGwyaU1ifyqKPAQfEShAA0g-2dydtSCkNVXE48xbzW1K1xDiBtmQa_F/s400/tmntrepair1.jpg)
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