I was so close to being done with my DESW but now I have run into an issue. After being disassembled for quite some time I finally put everything back together and had the game running. I ran a few test games to ensure everything was working. I did notice that when a ball went down the left lane, the laser kick would kind of stutter and not shoot the ball back into play. After a couple of tries, the coil began to function properly and shoot balls back out into the playing area.

Not sure if there is any relation to the following but for completeness sake, after the above tests I did the following:

- powered off the game and re-ran the wiring from inside the cabinet up to the backbox (I originally ran the wire bundle up the middle of the three holes between the backbox and cabinet. This was causing issues putting the playfield down in play position due to the bundle interfering with the light sockets on the back of the playfield and back playfield wall).
- I installed LEDs under the playfield while the game was in lamp test mode

After the above, I powered down the game and placed the playfield down. Upon power up I hear and see the laser kick coil energize and stay energized and then I smell that smell. I immediately power off and grab the manual. Q1 on the PPB drives the laser kick coil. I check the backbox and sure enough, it's toast. I pull the board and replace the TIP36c and diode for Q1. I think I may have had to replace the transistor at Q1 before (I have had the pin for two years and it has been disassembled for just about that long so forgot but I'm fairly certain) so just for safe measures I also replace the laser kick coil with a brand new one.

I checked all connections in the backbox and underneath the playfield and they look good. I power the game on again and same result; laser kick coil stuck on and smoke from the TIP36c at Q1.

What am I missing? What should I be looking at as the culprit?

- Mike

So looking at the schematics (see attached), should I check Q23 on the CPU? Would that cause Q1 to immediately fry on the PPB or am I looking at a short to ground on the laser kick coil?

DESW_LaserKickSchematic_(resized).PNG

Thanks for the reply mikat. I checked Q23 and the 2N4401 on the CPU and they are good (same measurements on those as other circuits on CPU). I am swapping the TIP36 on the PPB.

I'll verify J1 and try that next but I have a feeling I'm going to be pulling that PPB and replacing the TIP36 again before the night is over.

Ok, I replaced Q1 and checked its associated diode and 220 ohm resistor. I connected the CPU and PPB back up leaving J1 (solenoids to CPU), J7 (laser kick coil), and J8 (50V for laser coil) unconnected.

I think I can connect J1 and power the game on without issue but I'm hesitant to connect either J7 or J8 as I haven't changed anything aside from the TIP36 and haven't found the root cause.

Thoughts?

- Mike

DESW_PPBSchematic_(resized).PNG

The coil is brand new and has less than 2 seconds of power to it; I replaced the original coil with this one after Q1 fired the first time. Even after the installing a new coil and new TIP36, the coil locked on and Q1 fried again.

So my plan is to disconnect both wires on the laser kick coil, connect J7 and J8 and disconnect J1 on the PPB. Then power on the game, correct? What will this prove/disprove? If the coil does not lock then the problem is on the PCB, if it does then it is the PPB or under playfield?

Ok, so I removed both wires to the laser kick coil and disconnected J1 on the PPB. I powered the game on and touched the wires to the laser kick coil... No lock and Q1 is not fried.

Should I connect J1 and try again?

- Mike

I reconnected J1 and touched the wires to the laser kick coil and no locked on coil and Q1 is fine. Weird!

I'm going to re-solder the wires to the coil and keep my fingers crossed.

I resoldered the laser kick coil and simulated a game (I still have to put rubbers on the flippers, fasten the wireframe trails, and wax) but so far so good. I'll keep my fingers crossed and knock on wood that nothing else happens, my son is itching to play. It will be a nice surprise for him when I get home from work tomorrow and sit him in front of it.

Thanks mikat for your assistance and taking the time to reply and help me out. It is very much appreciated!

- Mike