Rottendog MPU. Williams system 11. F-14

[Luckydogg420]

I can here the old school professionals cringe, why replace when you can repair?

My f-14 has a couple on going issues that are hidden in the MPU board. It might just be bad roms, blowen transistors or a bad trace. I know electronics, but I'm not a board repairman. I've replaced chips, but don't own an oscilloscope. So I decided to go new.

My current MPU board has been fixed at least 7 times in the past and I think theres 3 other issues hiding in the game. 1) some sounds don't play. 2) there seems to be a logic problem with the top ball diverter, it works, just not when it's supposed to making multiball almost impossible to achieve. 3) I'm pretty sure last time I was working on it I shorted 70v back into the switch matrix along the pop bumper switch.

I know, I know, these can all be fixed, but in my quest to make it better then new, I decided to go with a new PCB. Even though some people disagree that a repo board can be as good as original. I ordered new game roms and sound chips with the hope that everything will work like new, with new parts. I didn't realize that there are chips located in collingwood....kinda bummed that I didn't order local. But I didn't find them untill days after my parts were ordered.

If there's a board guy that wants to offer me something for the old board, then I'll likely sell it. Just pm me. But be warned, there are issues.

I'm planning to get to this install this week. More pics to follow

 

[Luckydogg420]

The new roms that I ordered are the game roms L-4, sound roms and speech roms.

Currently my machine has L-1 roms. I haven't found and documented difference between the L-1 and L-4 roms, other then one post saying that L-4 might have reduced scoring, taking a zero of each valu. I don't know, we'll find out I guess. If I don't like the L-4 roms, then I'll just put back in my L-1 roms.

Also:
The rottendog board doesn't ship with a CPU. F-14 has a 6802 CPU chip, I could have pulled my old CPU to reuse, but thought I might as well get one too.

Here in Kitchener, Orion electronics on Lancaster st. have them in stock so I went to pick one up on the way to work.... The lady behind the counter said "I don't know if you will have to program it, or if it will work"... I didn't think of this.

Please someone with pcb knowledge, Do I need to program this new chip? Or will it work? (I assume all game info would be in the game roms and the CPU just crunches numbers)

My friend is an electrician, and his co-worker makes boards for fun and programmes chips all the time, he's already said he'll help me if I need anything...might be time to take him up on that offer and learn a new skill in the meantime.

 

[Menace]

Nothing wrong with buying a repro PCB at all, especially if there are gremlins in the original that just never seem to go away. I even bought a replacement driver PCB for my old Strikes n' Spares because one of the FET's went up in flames (common with FET's) and the carbon damage to the PCB was bad enough to warrant a replacement. (Carbon damage is conductive and can be a real pain to eliminate)

Keep us posted on the install, and if it solves all the issues you mentioned.

D

 

[Luckydogg420]

New game chips came in yesterday.


There's 2 game chips, 2 sound chips and 2 speech chips.


I started installing the new chips into the new board. The CPU went in first.


The new board has a daughter board that sits on top of it to handle some sounds. So after the game chips went in the main board I installed the 2 sound chips and 2nd CPU (6802) onto the daughter board, and then placed the daughter board onto the main board. The last 2 sound chips get placed in the existing sound board in the backbox.


Final touch is install the new board

 

[Luckydogg420]

I didn't have a lot of time last night, so I only played a couple games, but so far I'm happy. Everything is working but the pop bumper. This doesn't surprise me, I think he switch is pooched, the didn't register in switch edge test.

The game is now making sounds I've never heard before. Yay. It's not much but now I have 4 new noises that didn't know about.

The upper all diverter is also working properly. It's supposed to send the ball to the kicker that will send the ball to around the top loop, so that your set up for a shot on the "T O M" or "C A T" targets depending where you need to hit more. Then it's used to to send the ball into the locked spots for multiball. Before it would send the ball wherever it wanted and rarely it would send the third ball to its lock, making multiball almost impossible. Before you would have to shoot the up kicker a dozen times before it would send the ball to the right place. Now it works properly.

There's very little difference between the L-1 and L-4 roms. I noticed the L-4 roms have a couple different adjustments. One was to install "add a ball". I've never noticed that before in the old L-1 roms