Hey,
One of the most common problems with Ivan Stewart's Super Off Road boards... seemingly the Track Pak in particular, is a problem where the track is shifted up by a half of screen (though you still drive the normal track). Several people had reported that deconverting the Track Pak board to the original Super Off Road fixed the problem, so it was related to the Track Pak chips.
The Track Pak conversion involves swapping around 24 chips (22 EPROMs, a PAL, and an EEPROM). So, the assumption is that the board itself is fine, but one of the Track Pak specific parts is defective.
I had this problem on a boardset 10+ years ago, and threw the board into a box... seemingly never to be found again. Well... I happened to come across it a couple weeks ago, in my attic! I have a working Track Pak cab in my basement, so I figured I'd try to track down the culprit.
The problem, at least in my case, was the serial EEPROM at U120. Simply swapping my good one into the bad board fixed it, and swapping the bad one into the good board broke it. I peeled the label off the good one, and found it's an NMC9346N, which is a fairly common EEPROM. I dumped it, but found that the contents didn't really matter to the game. It looks like the game will initialize the EEPROM as needed (so it's not a "security" chip)... but in my case, it couldn't write (or read) the bad EEPROM, which probably made the game freak out.
A big hint that your EEPROM may be toast is to look at the country list when you enter your name. In my case, I was given multiple options of Belgium and Australia.
I don't know whether the Track Pak conversions used a cheap EEPROM, which commonly fails (maybe even had a low number of write cycles and simply "wore out"), but comparing the conversion EEPROM to the 3 other Leland boardsets I had, the bad one was unmarked, compared to the marked NMC9346N on the other three.
Anyway, a suitable modern replacement is the 93C46B... available from Digikey for $0.28 ( http://www.digikey.com/product-detail/en/microchip-technology/93C46B-P/93C46B-P-ND/254225 ). You need to make sure to get the 'B' variant (64 x 16-bit), as there are 3 types... a 64 x 16-bit ('A'), 128 x 8-bit ('B'), and one selectable with a pin ('C').
The chip is on the bottom board, just below the connectors at the top. You can easily access it by disassembling the stack, though if you have small fingers and are careful, you can swap it by reaching between the board stack. Note the orientation has pin 1 facing down.
The EEPROM looks to hold settings, statistics, etc. (maybe shared with the battery backed RAM)... so after replacing the EEPROM, you'll want to go into setup and set your coin settings, clear statistics, reset the country selection, etc.
DogP
One of the most common problems with Ivan Stewart's Super Off Road boards... seemingly the Track Pak in particular, is a problem where the track is shifted up by a half of screen (though you still drive the normal track). Several people had reported that deconverting the Track Pak board to the original Super Off Road fixed the problem, so it was related to the Track Pak chips.
The Track Pak conversion involves swapping around 24 chips (22 EPROMs, a PAL, and an EEPROM). So, the assumption is that the board itself is fine, but one of the Track Pak specific parts is defective.
I had this problem on a boardset 10+ years ago, and threw the board into a box... seemingly never to be found again. Well... I happened to come across it a couple weeks ago, in my attic! I have a working Track Pak cab in my basement, so I figured I'd try to track down the culprit.
The problem, at least in my case, was the serial EEPROM at U120. Simply swapping my good one into the bad board fixed it, and swapping the bad one into the good board broke it. I peeled the label off the good one, and found it's an NMC9346N, which is a fairly common EEPROM. I dumped it, but found that the contents didn't really matter to the game. It looks like the game will initialize the EEPROM as needed (so it's not a "security" chip)... but in my case, it couldn't write (or read) the bad EEPROM, which probably made the game freak out.
A big hint that your EEPROM may be toast is to look at the country list when you enter your name. In my case, I was given multiple options of Belgium and Australia.
I don't know whether the Track Pak conversions used a cheap EEPROM, which commonly fails (maybe even had a low number of write cycles and simply "wore out"), but comparing the conversion EEPROM to the 3 other Leland boardsets I had, the bad one was unmarked, compared to the marked NMC9346N on the other three.
Anyway, a suitable modern replacement is the 93C46B... available from Digikey for $0.28 ( http://www.digikey.com/product-detail/en/microchip-technology/93C46B-P/93C46B-P-ND/254225 ). You need to make sure to get the 'B' variant (64 x 16-bit), as there are 3 types... a 64 x 16-bit ('A'), 128 x 8-bit ('B'), and one selectable with a pin ('C').
The chip is on the bottom board, just below the connectors at the top. You can easily access it by disassembling the stack, though if you have small fingers and are careful, you can swap it by reaching between the board stack. Note the orientation has pin 1 facing down.
The EEPROM looks to hold settings, statistics, etc. (maybe shared with the battery backed RAM)... so after replacing the EEPROM, you'll want to go into setup and set your coin settings, clear statistics, reset the country selection, etc.
DogP





