So I have a Zaccaria Time Machine that I've had for several years. When I got it it had some burned connectors on the power supply board and I replaced all of them with .156 headers and trifurcon connectors. Just a few days ago I could smell a slight plastic burning smell coming from the game. Opened it up and pins 9-12 on CN1 were burned to a black crisp. These 4 pins supply 6.5VAC to the AC legs of a bridge that then supplies 5VDC for use in the game.

The circuit is simple. The transformer has multiple taps with wires with different voltages going out. They took 2 wires in parallel from each side of the tap for the 6.5VAC. One side goes through connector CN1 pins 9 and 10 and the other side goes through pins 11 and 12. Pins 9/10 feed a 15A fuse (F3) then connects to the A/C side of a bridge.

So pins 9/10 and 11/12 on that connector were burned bad. The fuse clips for F3 were tarnished. The game worked perfectly with no issues just had that burning smell.

I removed CN1 and replaced it with a new .156" header from pins 1-8. I then took 18 gauge wires and soldered them directly to the solder pads on the board where header pins 9/10//11 and 12 were supposed to go. I put a square 4-pin Molex 0.093" connector on the end of the wires so you can still disconnect everything. I replaced the fuse clips with new high current clips a new 15A fuse.

The game is still working fine, but the wires get warm. The connector seems fine but the fuse gets so hot you can't touch it. It doesn't blow the fuse. I put a clamp-on ammeter to measure both sides going to the bridge and it varies from 9A to 15A (jumps around) during attract mode.

What would cause this issue? Is it normal? I attached a picture of the schematic and there's nothing there I can see that's causing this. Like I said the game works fine. The fuse is in tight and right now it's shiny but I'm sure the heat will change that over time.
Zac.png

Those connectors are on the output of the bridge and they are fine. The test points are good, the connectors are fine and not hot. It's just the AC input to the bridge. A bridge typically opens and then you get no output voltage or it shorts and blows the fuse immediately. This does neither except the connectors and fuse gets really hot. It's not drawing a huge load because the fuse isn't blowing. That's what's weird.

I suppose I can solder in a new bridge and see if that changes anything. Not much else it could be.

Yes it's for the lamps, but I did read somewhere where the Gen2 Zacs use a signal from the GI circuit to initially boot the game. I think on Clay's repair guides I read that. I'll drop the backbox or playfield GI connector and see if this helps. Thanks.