If you don't feel up to continuing.

Have you measured all the fuses again in the backbox?

It takes some seconds for a R & B to boot, have you waited some time ?
When it is booting, indeed the display nor the feature light work.

About the 3 leds on the MPU board; the start up sequence should be:

•PIA (Peripheral Interface Adaptor) and +5 volt LED turns on immediately.
•After about 1/2 second, the PIA LED turns off.
•Blanking LED turns on next.
•+5 volt and Blanking LEDs will stay on (until the game is turned off).

And "it's showtime" says that your soundboard is booting, nothing more or less.
When you boot the machine with open coindoor you'll hear some additional music to it.

You say you replaced Q3, but Q2 is shown to have circled which pins you were getting low ohms on. Was that just a reference of what you were comparing Q3 to?

What pop bumper was it that was locking on when you turned on the machine?

Seems my R&B is having a problem now too. I can see I don't have +5v LED on when my display goes out and my machine shuts down until 5 volts returns. I think we may have different problems.

I think you need to measure +5v and +12 volts when your machine is acting up.

I've found when all else fails, just buy a new board. I've done that with 3 different boards in my R&B machine, and it works like a champ now (PSB, DMD, SSFB). Although I intentionally avoided Rottendog boards because there are so many horror stories about the shoddiness of those products.

It would be good to measure the voltages at the DMD power connector once the machine acts up.
5, 12, 68, -98, and -110VDC for the Dot Matrix Display

Oh that is cool. I would stay away from Rottendog MPU boards.
I bet you could find another working good shape DE MPU off of Ebay for a little cheaper than RD board.

Good chance that you can use some freeze spray to make the board go good and heat gun to make it fail again. I would suspect one of the PIA (40 pin) IC's as the cause.

My machine definitely is power supply related right now.

I just fixed my rocky and bullwinkle. It had a problem with 5 volts cutting out. Sometimes the game would not turn on either, and of course the DMD was out when the game acted up.

I think you need to replace the C2 also on the power supply as I had. This 100uf 25 volt cap leak and looked like there was solder flux under the capacitor. This is actually the internal of the cap leaked out. Bad part of this is that it eats up the trace and feedthrough below it. Replace with a 100uf either 50v or 100v cap.

Problem I nrntioned was a power supply board failure, not the CPU board.

Do you have any of the 3 red LEDs on your CPU board?

Unplugging a power connector from any board while a game is on is a potential for damaging a board.

Have you tried the CPU board in another game?

I am in total disagreement on that. You are now sending more current elsewhere when you do this, especially if you have all the boards connected.

Does the F5 ever blow out when you only ever turn the game on and off using the power switch? Or it is only when you disconnecting the power connector from the MPU?

I actually would like to see a picture of your Power supply and CPU in 2 separate pictures.

I do not suggest that as more troubleshooting is needed. There are other parts I had seem cause the PIA to stay lit.

Did you connect the CPU board into another game with just the power connector and see the same boot up failure?

Bump from the dead for a 'similar' problem as the OP.

I bought the game about 6 months ago, was playable, just been fixing some small gremlins. Will do a tear down, cleaning, plastic replacement, pop rebuilds in the near future. The game came with GameRom 1.1 in the C5 position and Display Rom 1.3 (Rom0). I wanted to update to GameRom 1.3. Ordered off Marcos, which says if micropro6802 - GameRom goes in B5.

So, I put in the 1.3 Game Rom, I get 'its showtime' and lights on, but nothing on display and non-playable. I can put the Rom in either C5 or B5 and same thing. I switch back to the 1.1 and it fires right up and works 100% (This is in the C5- despite having the 6802)

Did I just get a bad Game Rom from Marcos? or is there another step in there i'm missing for some reason?

Regarding the processor (6802 or 6808) and socket (C5 or B5) I'm just going off the 'installation note' on the Marcospecialties page. I'm totally a newbie at messing with these.

Did you put that rom in right. The notch faces a certain way. Don't go by the label that Marco puts on them. If you put it in backwards then it smoked instantly.
If not you have a bad ROM

Don't worry about the microprocessor, if the game is booting then it's fine. It has nothing to do with what rom version you are running