Sea wolf torpedo not firing

[manadams]

Does anyone know what chip or chips control the torpedo fire on the 8080 board? I've got my sea wolf almost fully working with the exception of the fire not working, tested the switch and wire continuity to the board so it's not that. The test rom shows it stuck high but was not firing at all before the test rom was installed.

 

[mecha]

stuck high means it's not active, ever. low = grounded/activated.

you will thus need to go schematic hunting to see what chip it runs to.

 

[manadams]

stuck high means it's not active, ever. low = grounded/activated.

you will thus need to go schematic hunting to see what chip it runs to.

Can't really find anything outside of the parts catalog which doesn't show much. I guess I need to learn how to use a logic probe.

 

[Lurch666]

9th picture down

This is a link to a repair log where it shows the opto isolators used for the controls. Maybe one of those is dead?

 

[wugly]

fire switch goes into chip d1 pin 9 which is an inverter chip on game board. output of d1 is pin 8 which should be opposite of 9.

it then goes into d4 which is a 74153 pin 11. it comes out on pin 9 ang goes into c4 pin 9 which is a buffer and comes out pin 8 and feeds thru the mx data bus back into the main board mx5 which is labled q one of those 3 chips might have a fault in the inverter or buffer. make sure d1 pin 9 actualy is charged to 5 volts before hitting trigger

 

[wugly]

 

[wugly]

 

[wugly]

basicly you should see on c4 pin 9 and 8 low when trigger not pulled and high when it is d1 pin 9 should be high with no trigger and low when it is pulled pin 8 should be low when not pulled and high when pulled