Maybe you have a coil that is locking on. See if a switch is closed that would cause a coil to stay on.

I just happen to have a Sweet Hearts in my shop all torn down for restoration. Your problem is descriptive of a reset bank issue. Since you're new to all of this, I'll explain in detail:

Sweet Hearts (SH) is a pin from 1963 that uses what Gottlieb refers to as a "Reset Bank" which is activated when the Start Button (red button on coin door) is pressed. This Reset Bank is a GIANT physical bank of open contact relays all suspended from the bottom right side of the playfield. The relays in this bank are mechanically reset by a long steel bar that's actuated by a pair of pretty large 110V solenoids. The reset bank with its myriad of associated switches/relays are frequently the culprit in older pins. And SH has a truly massive reset bank!

Lets take a look at the playfield underside and I'll point out a few things:

Note the Reset Bank which is the entire area inside the RED line. Its massive and has two solenoids firing together to actuate the physical relay reset bar. The solenoids are inside the YELLOW boxes. Watch out on these: they're running on 110VAC. Another noteworthy item in the pic are the two 1A "slow-blow" fuses, here circled in GREEN. These are protecting the reset solenoids from over amperage, which could easily cause a fire if one of them got locked up somehow.
SH_PlayfieldBottom (resized).jpg
Now there are a few other fuses in SH. Three of them are on the electric panel / tilt bob board on the left side of the cabinet just inside the coin door. I have this board out of my SH at this time, so it was easy to photograph all by itself. The top most fuse should be 10A and is there to protect all the 5V lighting inside the head box (Gottlieb calls this the "LightBox"). The middle one should be 15A and is there to protect the playfield lighting (its labeled "playboard" on the original placard). The bottom one with the red/red+white wires should be 10A and is there to power and protect the entire playfield mechanical system. These 3 fuses are pictured below:
IMG_0490 (resized).JPG
There's another fuse in the game I want to point out. Its a 5A slow-blow and wired straight on to the power cord, and transformer primary winding. Its on the main board, way in the back. Circled in YELLOW in the picture below:
SH_MainBoard (resized).jpg
Now on to schematics. Lets have a look at how SH is wired and how the Reset Sequence works, at least as far as getting the Bank to physically reset. In the schematic snippet below, you might only recognize a few things: There's the wall plug, the main transformer and a few items related to the coin chutes in there. No problem; we'll take things slowly one step at a time. In the schematics shown, I'll highlight those parts of the circuits in GREEN that are powered on so you can easily follow what's being explained.
In the first pic below, this is how the game will be when simply plugged in to the wall and the "Replay Button" has NOT been pressed yet. Its this button - the Replay Button - that when pressed will set the whole Gottlieb Reset Sequence in motion and serve us up a new game. Also note here that the main transformer is NOT powered on. We must make contact across the primary winding of the transformer for it to make power. (Most older EM's have transformers with a single primary winding running on 110VAC and 2 secondary windings; one at 25VAC for all the game mechanical stuff and a 5 VAC secondary for all the lighting)
SweetHearts 01 PluggedIn (resized).jpg
The way contact is initially made to power the main transformer up is across the Replay Button and the "S" relay contact set. The "S" relay is the Start Relay and when its energized the entire Start Sequence is initiated. The way we get power across the Start Relay coil is by pressing the Replay Button.
Looking at the schematic again, you'll also see in there another switch - a normally open contact pair - called the "Zero Position Replay Unit". This is a switch that's connected to a thing called the "Replay Unit" which is located inside the head box. Its the thing that counts up/down to indicate how many "replays" or "credits" are left on the game. We usually call this thing the "credit unit" and there's a switch inside this unit that will open up when the credit unit is on zero plays remaining. For many older EM pins, what we do is solder or clip a short jumper across this contact set so that when the credit counter hits zero, there's still continuity across this switch. Whalla! No money needed ... and we shall assume in the following discussion that this jumper is in fact in place.
I'm going to show how things work in a sequential way, but in reality much of it all happens nearly instantaneously.
SweetHearts 02 ReplayButtonPressed (resized).jpg
So the circuit completes through: Replay Button / Motor 1C (it should be closed) / Zero Position Replay Switch (jumpered closed) / "W" (extra chute: you won't have this probably) / and "On Ball Release" (solenoid and switch that releases the balls from the trough. This side of the switch is now closed) -> powers on "S" relay which closes "S" contact set and completes the 110V circuit that powers on the main transformer.
The next pic will show how the Reset Sequence, including resetting the Bank is accomplished. Note in the next pic the 25V secondary winding of the transformer is shown powered on. There's *another* set of contacts on the S relay that also alternate open-closed that will directly power up the Score Motor. This is a special switch called the "S Armature" switch and it has 2 alternating contact sets. When the Start Relay closes it also is physically connected to the S Armature contact set. So closing the S Armature switch will cause the Score Motor to run through what we call a "cycle" which is 120 degrees of rotation. (the Score Motor is what turns that small circular turn-table type system down on the main board with a BUNCH of switches all around it)
With the S relay coil energized, the contact set (circled in YELLOW so you know exactly what I'm pointing out) alternates closed so as to power the Score Motor ON while removing power from the rest of the game's physical components. Brilliant! - (sort of):
Score Motor Running
Now with the Score Motor (SCM) turning, we close a switch on the #4 SCM switch stack labeled "4C" in the schematic. This switch is in the SCM stack, but its also carrying 110V so be careful in there with everything powered up. The other switch that needs to be closed is called the "S Armature" switch (pictured below) which is nothing more than a switch mounted onto the bottom of the Start Relay that also will close when the Start Relay is pulled shut. Here's a pic of the "S Armature" switch on my Sweet Hearts:
Start Armature Switch
Now the final schematic: Look at how on the 110V side of the transformer we carry power through SCM 4C / S Armature -> Bank Setup Coils (2 of them) which pulls both of those beefy bank reset solenoids closed and resets the bank!
Bank Reset Coils Energized
So there you have it: The entire first part of the Gottlieb (old) EM game reset sequence. This is only the "first part" - where we get to resetting the Bank - but there's LOTS more that must happen to get a game started. The score reels all have to be reset; the credit counted decremented; the balls released from the trough and the playfield equipment powered up.

Take what you learn here, do some investigating, and report back. We'll have you going for sure!

Cheers,
Bill.

Hi FlashCannon94
lets say a big "Thank You" to SilverWings , Bill. Greetings Rolf

The hold relay on these games generally need replacing. It holds the 110v to the transformer after the initial motor spin that Bill mentioned. If the coil is weak its not holding in. One quick test I do with any new 60's machine is open it up and manually depress the hold relay and see if it will "hold". The only contacts on the hold relay is a red and black pvc coated wires (110v leads are pvc coart, cloth ate 25v and 6v). Its fairly easy to spot. this coil use usually on my first pbr order.

From what you suggest, with the power dropping out it is probably the hold relay. With the game unplugged you can jumper the red and black leads closed and then plug it back in, the game should light up.

Some people leave the hold jumpered and then use a switched strip to turn them off and on. for me I just open the coin door and lift the slam switch to turn the machine off. Made the mistake of doing this in my bare feet on concrete one time (well maybe twice)

Here's the hold coil "R" , it stays on for the life of the game. You'll see a R contact in the chain in the 110v section, ie holds the 110 on, with in turn keeps the 25v to the R relay

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