If it's the original masked rom (no window/sticker) just replace it with a burned eprom and change the jumpers. Most people just change the jumpers on their -35 bally boards to take 2x2732's in u2 and u6.

U1/U2 are game specific. U6 is a common system ROM shared with a few games of that era. Any of U1, U2 and/or U6 ROMs being bad will cause no first LED flash.
Replace with 2732 EPROMs as slochar mentioned.

If you peel the sticker off and it has a little window on it, it's just an eprom and can be replaced with another eprom, which lots of people can burn.

I'm saying that a lot of people just convert all their boards of that era to use the same 2x2732 eproms - the one in u2 replaces both u1 and u2, and the one in u6 replaces both u5 and u6. If you really wanted to you could have eproms in u1, u2, and u6 on your machine. What the first flash not happening is telling you is that one of the rom chips (whether it be a masked rom or an eprom.... the software can't tell) is failing its checksum test. It might be the u6 chip or it could be either of the u1 or u2 chips. It tries to test all 3.... in all probability u6 might be ok since that's where the bootup code actually resides to turn OFF the led when you turn the machine on.

This is also why you should just either convert to 2x2732 and order 2 replacement eproms that way or order all 3 if you want to stay original (assuming all 3 are already eproms... this way you don't have to change any jumpers on your board)

Try removing/reseating u1, u2, u6.

Post a picture of your MPU board so we can see exactly what ROMs are fitted to your board.

First do the easy thing that frenchmarky mentioned, the problem might be a ROM socket - does this board have battery corrosion? Do the pins on any of the ROMs look badly tarnished?
If the problem persists you'll need to look at swapping the ROMs for EPROMs and while you're at it consider using optional freeplay code.

These games all have the same U6 ROM (Bally E720-35) as Rolling Stones - if you have access to one of these games, you could try swapping U6.

Nitro Groundshaker
Silverball Mania
Harlem Globetrotters
Dolly Parton
Future Spa
Rolling Stones
Mystic
Viking
Hot Doggin'

If it's an E-prom with a covered window the Prom might have failed. Hard coded Roms seldom do unless they have been poorly stored. before panicking and ordering chips I would check the chip itself and the socket. Carefully remove U6 and clean the leads. Look over the socket and the soldering.
Over time the leads on those chips become highly fragile so take note when I say careful.

Post some clear pictures of this MPU board especially around the corrosion and ROM sockets.

What happens when you manually reset the board by briefly shorting pins 39 and 40 of the 6800 CPU at U9? (pins 39 and 40 are top two left most pins on that chip).

There's some corrosion that wasn't addressed on the board. You might have some still active under the U8 RAM chip socket which could be causing resistive shorts between the address/data lines.

You should remove the ROMs and carefully clean the legs with one of those small brass wire brushes. Solder a component lead on the broken leg stub of the U2 chip and cut it same length as the other legs so you can plug it back into the socket as normal.
The legs on U1 and U2 ROMs look tarnished, U6 legs on the top side look a little green though I can't see much of its legs.

You haven't said anything about voltages, I just fixed a Dolly Parton the would just flash once.
It wasn't getting the 43 voltage for the coils.

That is interesting. I thought that was the last thing it checked for on the 6th flash or so.

If U8 is bad you should still get some blinking. You can pull the chip off of the board and try the flash sequence, but its probably not causing the lock up.

Those masked ROM chip legs are plated with something bad that tarnishes black and eventually rot away. I would try backing out the ROM chips just slightly and then push back down in the socket to get some wiping action with the chip socket. Look to see if any legs that are broken when you back out the chip. Those fairchild PIA chips often have the chip leg rot too, but they dont look as bad as the ROMs do in your picture.

Other not evasive stuff to try is new PIA and CPU if you have any on hand or could borrow from a different PCB.

I am sure we have all seen worse run fine for years but you would not be out of line if you shipped the buck sixty for a new board. Rolling Stones is a good game, I actually prefer the old one to the new one. I believe it would add value if you ever sell the game. I am considering buying one of them just for stock. Good luck which ever way you go.

Off topic, to barakandl guy. Any thoughts about making a Gottlieb system 1 CPU? I am sick to death of shipping $240/250 for a Ni-Wumph. System 1 CPU's are a pia not worth fixing.

nah I don't think so. I'm not smart enough to design around those obsolete spider chips and a couple people did solutions already.

There appears to be numerous hacks on the board in past attempts to get it up and running. I would advise throwing in the towel at this point and buying a new board unless you are genuinely interested in, (and have the time), learning how to repair.

Aahhhh common', get one of those out there for around the 150 mark and you will sell a crap load in no time. You must have a Ni-wumph laying around. I wonder if they even have $25 bucks into making that. I have bought some of your stuff and it's great. I will be buying one of your Bally/Stern MPU's, that's a excellent price for such a versatile board.

If you are getting a new MPU you still may want to consider changing out the connector pins. With all that corrosion around that one connector The new MPU may still give you problems just something to think about.

Hah! I get it. Nice post. Let us know how it goes and if you need to add some Brown Sugar.