Area 51 gun issue

Wayne104

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Having an issue with player one gun socket on pcb board. Whenever a gun is plugged in it doesn't recognize the triggering. If I switch the guns they both work fine in player 2. Anybody know what this could be? The gun motion is detected in the test screen just not when trigger is pulled.
 
Don't recall the inputs on that board but many gun games use a 7414/74LS14/74HC14/etc... on the inputs. If yours has that chip, replace it.
 
Don't recall the inputs on that board but many gun games use a 7414/74LS14/74HC14/etc... on the inputs. If yours has that chip, replace it.

Does that ic control both guns or just one. The player two gun works fine and have no issues. Where us that ic located on the board?

Atari's schematics for A51 don't appear to show the gun input circuitry.

Channelmani(a)c is, as usual, spot-on. I looked at the A51 board I've got upstairs, and there is an LS14 right near the gun connectors. The only bad news it, it's surface-mount, not thru-hole. I have every expectation that it handles both guns. However, sometimes a whole chip doesn't go bad, but just a single "gate" inside of it. If you want to be certain, you'd need to trace the lines from the connector to the LS14, and see if the line for your bad trigger is being inverted properly... or you chould just replace it and see if that does the trick.
 
Same issue (repair log)

I just had the same issue with my Area 51. P1 gun trigger wouldn't work. I did some digging and the voltage at pin 2 of the gun connector was only 2.1v on the P2 gun pin 2 was 3.5.

I was able to trace the signal to the 74HC14 right next to the gun connectors.
Pin Signal
3 Gun 2 trigger in
4 Gun 2 trigger out
11 Gun 1 trigger in
12 Gun 1 trigger out

Grounding the trigger input should pull the in low and then the out should go high. On the P2 side that worked as expected. On P1 it didn't. I used a jumper from 5V to momentarily touch pin 12 and verify that the trigger signal was being processed by the board (in the controls test screen).

I removed the suspect IC (using a SMD hot air station) and then checked the values at pin 2 on the two gun connectors. Both were at 5v (it was possible the pull-up resistor was bad, this verified that was not the case).

Installed a 74ac14 in the location and the board now triggers on both guns as expected.

Note: A second set of A51 boards has a 74LS14 at that location, so it is not a critical part to be in the HC / LS family.
 
I have an Area 51 which is not tracking guns on Player 1, but works fine on Player 2 WITH THE SAME GUN.

I'm suspecting this chip mentioned in this thread (and others). Has anybody had this chip fail to where it takes out the optic tracking?

Want to make sure the chip in question doesn't control JUST the triggers... as that is not is my problem. My trigger works fine, unlike why this thread was created.
 
I have an Area 51 which is not tracking guns on Player 1, but works fine on Player 2 WITH THE SAME GUN.

I'm suspecting this chip mentioned in this thread (and others). Has anybody had this chip fail to where it takes out the optic tracking?

Want to make sure the chip in question doesn't control JUST the triggers... as that is not is my problem. My trigger works fine, unlike why this thread was created.
I am wondering the same thing appears as it is the issue with my board too. Guns wiring monitor all good tested with site 4 board. On original Area 51 triggers flash screen no tracking. I'm also thinking of trying the ls14 ic.
 
I have a similar problem on my dual layer board.
Player 1 works fine. Player 2's tracking is fine, but the trigger does nothing.
It's not the gun. Swapped guns and issue remains on player 2 side.

Where do you get the replacement chip?
Looks like 74LS14 or 74AC14 SOIC chip.
 
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I have a similar problem on my dual layer board.
Player 1 works fine. Player 2's tracking is fine, but the trigger does nothing.
It's not the gun. Swapped guns and issue remains on player 2 side.

Where do you get the replacement chip?
Looks like 74LS14 or 74AC14 SOIC chip at E23.
I had to fix this on one of the Area 51s that came through a few months ago. I believe it's 74LS14. as for the part, I think gamefixer had 1 left, so I had one chance to make it work. lol

as for a source for the part... I'll have to look into that.
 
On my dual layer board, it is a Motorola LS14D.

I have some junk Big Buck Hunter boards. I see 2 Texas Instruments LS14 chips on there.
Wonder if I can use one of those.
 

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Sometimes I amaze myself.
Well the Texas Instruments LS14 donor chip from a bad Big Buck Hunter PCB I had worked perfect.
I'm not the best at surface mount soldering, but it works now.
Both gun inputs now track and shoot.
Thanks!
 

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