Missile Command PCB - Works with Braze Kit installed. Watchdog kicks in without it. ROM issue?

RobotWorkshop

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I had a couple broken Missile Command boards and a friend asked me to fix his board too so he can finally get his game running again. I was able to get one of my boards totally fixed and running well. I think I have most of my other spare board working now. Just need to test that in my cabinet.

The one giving my trouble is the board for my friend. I have most of that working. If I plug in the Braze upgrade the board works and plays perfectly. But, if I remove it the watchdog kicks in and constantly resets the board. The DIP sockets for the processor, Pokey, and ROM's were all replaced. I've tried a know good set of ROM's and a known good set of EPROM chips. Same results. Is there anything other than the ROM's that aren't used with the Braze kit is installed? Just going to go back over all the chips dealing with the EPROM selection and buffering of address and data lines.

I should also mention that the DRAM was removed, all 8 new sockets, and installed modified 4164 chips that are all plugged in. Made it easier to test on the bench since only 5V is needed. Since the Braze kit runs well and game plays the RAM seems fine.

From the markings on the board it seems that the revision is -04 and it uses a set of six 2716 type devices for the ROM storage.

Any thoughts on where to check next?
 
I think I may have found it. It seems that the ROM select lines for ROM7 and ROM11 are shorted together on the board. Now to trace down that fault and find what is causing it. Solder bridge, lead bent and shorting, etc.
 
There was a very, very tiny piece of debris barely shorting two pins at R2. Cleared that and not the board boots and runs without the watchdog kicking in. Just need to try it in the cabinet later tonight.
 
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