Data East Lethal Weapon 3 machine.
Current situation:
Ball launcher coil melted down 10 days ago: it was stuck on.
Replaced the coil, still stuck on.
Accidentally blew the new coil with incorrect wiring, replaced again.
Found the transistor was an open circuit, and since there were other issues on the PPB, decided to replace it.
New XPin PPB installed today, ball launcher coil still doesn't fire in game or diagnostic mode.
When a new game is started and the trigger is pulled, it makes the sound like a gunfire from the sound board, so the CPU knows the trigger was pulled, but the coil doesn't fire.
There is voltage to the coil. Like other coils, it jumps between 78v and around 20v.

I'm just not sure what direction to go in tracing this issue right now, and it's getting pretty frustrating, not to mention expensive. Any help is appreciated.

#2 2 years ago

JSA

sidetrackedbrew

Sidetracked Brewery

Morganton, NC

2y 45,800 109 8 19

UPDATE: There is now no voltage at the coil after the machine has been turned on a few times for diagnostics. The XPin board has a note: "This XPin board requires fuses F7 (3A SB) F8 (4A SB) & F9 (5A SB) to operate, even if your original game board did not have these fuses."

F9 has blown, BUT there was a 4A in it, not a 5 (installed from XPin). However, obviously there is something that still caused this fuse to blow. But now I have a blown fuse that isn't even on the wiring schematic, so... where do I go from here?

#3 2 years ago

PGL

northvibe

Pinside+ Frequent

12y 121K 13,929

many times when replacing a coil and transistor they should be done at the same time so the diode on the coil and the transistor dont blow each other up.
Honestly. I would send the original board out for repair, get a new diode for the coil and dont test until both of those are replaced.

While the board is out for repair, verify continuity of that wiring and that it is connected correctly all the way back to the plug from coil.

#4 2 years ago

JSA

sidetrackedbrew

Sidetracked Brewery

Morganton, NC

2y 45,800 109 8 19

Quoted from northvibe:
many times when replacing a coil and transistor they should be done at the same time so the diode on the coil and the transistor dont blow each other up.

The first time I replaced the coil I wired it incorrectly and blew the diode up. I then installed a brand-new coil and diode, and then replaced the entire PPB, so effectively the transistor, diode and coil were all replaced at the same time.

Quoted from northvibe:
While the board is out for repair, verify continuity of that wiring and that it is connected correctly all the way back to the plug from coil.

I've verified continuity from the coil to the transistor on the PPB, and for the signal leg to the CPU. Everything on the CPU is visually perfect except for one small transistor on the upper right side, 3/4 of the board away from the coil signal wire. Not that it isn't related, but I haven't been able to connect it via the schematic...

#5 2 years ago

PGL

northvibe

Pinside+ Frequent

12y 121K 13,929

OP
Quoted from sidetrackedbrew:
The first time I replaced the coil I wired it incorrectly and blew the diode up. I then installed a brand-new coil and diode, and then replaced the entire PPB, so effectively the transistor, diode and coil were all replaced at the same time.

I've verified continuity from the coil to the transistor on the PPB, and for the signal leg to the CPU. Everything on the CPU is visually perfect except for one small transistor on the upper right side, 3/4 of the board away from the coil signal wire. Not that it isn't related, but I haven't been able to connect it via the schematic...

I mean if you wired it incorrectly, it may of blown logic on the board, not sure. that is a test that someone with knowledge of the schematics and process would know.

#6 2 years ago

JWH

Shogun00

Pinside member

6y 60,550 948 60

Check the fuses. You might have blown a couple of them, when you blew the coil.

#7 2 years ago

???

pins4u

Pinside apprentice

Gaborone

3y 34,400 1,037

You didn't "blow the coil'. You probably shorted the diode across it but it is very unlikely the coil was damaged.

Coils just do not give the trouble so many seem to think they do. It's just a coil of wire, nothing mysterious and, unless it overheats drastically and damages the insulation on the enameled wire, coils just don't give trouble.

Almost all problems are caused by wiring/crimps/plugs or driver transistors and circuitry.

You need to study up on EXACTLY HOW the circuit works and stop running off in all directions.

First confirm all voltages are present as required and described in the manual.

Then test the integrity of the wiring etc by momentarily grounding the transistor collector (the mounting tab) that is the driver for the coil in question (see service manual). This will tell you straight away if the wiring/plugs/sockets and the coil are OK or not and gives you a direction to look next.

If the coil fires when you ground the transistor tab - you have a board fault - if it doesn't, either you didn't check for the coil voltage OR you have a wiring fault.

Almost never will the coil itself be faulty.

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