Asteroids - Repair/Resore help - Beeping

[MaxAsh]

Hello All - Working on my first older restore (I've been working on newer mid 90's era machines only so far). I picked up an Atari Asteroids for almost nothing and I'd like to get it working again. The previous owner purchased it 4-5 years ago from a reputable local arcade repair shop. He said it worked great for several years (minimal usage), then he plugged it in recently and powered it on, but couldn't get it to work. Below are the symptoms, I haven't been able to find anyone with the exact same issue, so I'm stuck:

When plugged in and power switch turned on, the Player 1 and Player 2 buttons light up and stay lit
No monitor image
There is a constant rapid beeping, no change in tone, just the same beep over and over in a steady pattern without pausing.

My first instinct was to go flip the service switch... but there is no service switch (see image). Looks like it was removed, note the two quick disconnect wires just hanging there. First question: Can I just use any on/off switch or light switch I have lying around, or even an extra push button, to wire up temporarily?

I found it the beeping strange. All my reading indicated that the beep codes occur when the service switch is engaged, but since there is no service switch and he said it played fine until recently, I'm wondering why the beeping would be happening. Is play-mode known to beep on these as well if there are errors? I haven't found anyone else referencing a constant, steady fast beep on an Asteroids machine. Usually people have beep codes with some sort of pattern or high/low pitch changes. I do not, so I'm at a loss.

Thanks in advance for any replies! Looking forward to getting this machine up and running again.

EDIT/UPDATE: I found another switch labeled simply "TEST" on the coin door. You can see part of it in the upper right of the image I attached. When I hold the toggle switch down, the beeping tones become lower in pitch, but are still constant, and no image is displayed still. P1/P2 remain lit. I then hooked up a switch I had lying around to the missing service switch connections and when I engaged that switch, same result (low tones, constant, etc). Also, there is neckglow on the monitor.

[MaxAsh]

Just wanted to say I sorted the issue out for now. I ended up posting over on KLOV, which I should have done originally, and was given some solid advice. It turns out either the edge connector was not making a good connection, or a few of the chips were not fully seated. After reseating and cleaning those items, the game ended up coming on. Considering I got it for next to nothing and its in decent shape, I'm quite pleased. I'm not going to say I'm out of the woods yet, but it's looking good. I'll post some pics when I have it cleaned up some more.