Missile Command

I was looking for a Missile Command for a couple months to add to my Atari row when this popped up on Craigslist. I contacted the seller who was selling two (one working and one non-working). I was able to score the non-working and complete one for $100.

When I got it home I pulled the checked the fuses, pulled the game PCB and checked the voltages at the ARII board. Everything looked good except the +5V was low at 4.66V and not adjustable using the pot. Since the +5V was low I decided to plug the game PCB in and power on to test the voltages under load. After about 30 seconds I noticed smoke coming from Q2/R5 area of the ARII. I immediately powered down the game and pulled the ARII board.

Since I knew that I was going to have to replace Q3 (the 2n3055 transistor which handles the +5V) I decided to replace Q2, Q8 and Q9. Once finished I plugged the ARII back up and tested without the game PCB. I was able to now adjust the +5V but the -5V was reading high. After conferring with some fellow collectors on KLOV, the transistor that I replaced (from Bob Roberts ARII repair kit) runs high without a load. I plugged in the game PCB, powered the game on, checked voltages and all was fine but there was no picture on the screen. I put the game into test mode and received the audible sounds as expected. I exited test mode, coined the game up and it played blind. I walked to the back of the game to check the monitor and noticed that the video cable was not connected to the chassis. I powered the game down, attached the video cable and powered the game back on. This time I had an image but the horizontal sync has issues as seen below.

I tried to adjust it out using the horizontal freq/hold on the G07 chassis to no avail. Some research revealed that two incorrectly-valued resistors at R314 and R317 on some G07 chassis were installed at the factory.

"On many G07 chassis, the factory had mistakenly installed the wrong value resistors in the sync circuit. Double check yours to be sure that these resistors are the correct value:

R314, R317 (the ones most often incorrect)

R303, R306 (sometimes I found these were also wrong)

All of the above resistors are supposed to be 390 ohms, 1/4 watt. The factory had mistakenly used 4.7 k which of course is way off from what's supposed to be there. With these incorrect resistors in there, the sync circuit is too weak causing drift and or curl."

Feeling lazy and not trying to figure out what the cause was I ended up swapping out the monitor chassis with another working one. Game on!