Looks it might be a sample prototype based on the red label inside the cabinet. Might have been a test game or one used to make sure it met fcc requirements

Yeah it looks like a prototype. It looks similar to my friends, which a lot looks like prototype (no serial, generic cab art). I have a few question for you. Do you have a bunch of fuse housings with thick red wires under the playfield instead of the fuse board mounted on the left side of the backbox?
Also do you have a drop target blocking the ramp or a filled in spot where a drop target would have gone?

Just curious,
Mike

Interesting. What does the ROM labels say on CPU board?

Really glad to find this thread!
I recently found an HMM with the same cabinet and was concerned it had been hacked.

I'd still prefer the production artwork but nice to know it's probably factory.

I won't know more until next week, but now I know what to look for.

I wonder if there are examples out there with working drop targets at the ramp entrance? And what code they're running?

Really wish they had kept the drop target in hmm

Well, a friend picked up the proto/test HMM for me today. It's still a 6hr drive away so hopefully I can grab it soon.
Here are some pics of the different cab and, what looks like, a drop target that's been covered up.

If anyone know anything about the target I'd love to hear more.

Thanks

HMM_right_(resized).jpg

HMM_drop_target_(resized).jpg

I have a good friend that has a proto/sample HMM with the drop target spot also covered up. His appears to have been nicely covered up from the factory with a slotted in piece of wood.

I have tried to get him to look around for the wires and to hook up a single drop to see it there is code in the rom for it!

Damn, if there was confirmed code on the roms I would cut a hole in the playfield and run some wires. That would be so cool.

With the way the ball flys around in there I wonder if it was removed because of excessive damage.

that is my guess also, but with the metal aftermarket drops being made soon that would not be an issue.

I think I have more air balls in my HMM than all my other games put together...

Is that just the era of Bally machines? I don't own any others from this timeframe.

How do you think the balls and playfields will hold up. Will there be accelerated pitting of the balls?

nah, no added pitting to the balls.

From what I have seen the metal drops will take the burden of impact but are still solid.

I am waiting on some prototype ones now to try in a game.

I've had a few of these 6803 Bally pins (Special Force, Black Belt, Motordome, Strange Science and now HMM). They all seem prone to crazy airballs and funny ball movement. They are not what I would consider "smooth" machines, but what they lack in refinement they make up for in pure cheesy fun. The soundtrack alone on Black Belt or the bad 80's syth and crickets on Special Force always put a smile on my face.

The best thing to do is make sure your targets are not facing up and have new foam backers.

As for the drop. I have a couple of spare drop target mechs pulled from a buddy's extra Special Force playfield. They should be a perfect match. One is smart and one is standard. I would love to retrofit this in if it would work. I wonder who would be able to answer this?

that side art looks like the art on my bally hardbody from the same era.

I had a HMM about 10 years ago and really liked it. Fun game that doesn't get a lot of love.

Party Animal is good for airballs as well. Ill look at my friends HMM to see if they left any wires for the drop target. . . I think his is an early prototype as it didn't even have the fuse board. Just a butt load of in line fuses under the playfield.

So, if anyone was ever wondering what a factory HMM drop target looks like, here ya go!

20160315_235200_(resized).jpg

I finally got my proto/test machine home and, to my surprise, found an fully intact drop target mech and wiring. The only issue is that the coil wire was intentionally clipped and there's no code to support it any longer.

Looks like I'll have to hunt down some proto code... if it exists.

Here's my thread if you want to read more: https://pinside.com/pinball/forum/topic/my-proto-heavy-metal-meltdown-adventure