Anyone familiar with Moon Patrol Sound Board?

Okay, looking at the picture of an original Williams Board there seems to be an inductor XTAL2 populated which is missing on the bootleg Board:

Could this be part of a lowpass filter that might solve the issue when populated?

The schematics also mention an M5205 "Sound Synthesizer" which doesn't seem to be populated on either Board:

Maybe someone could have a brief look at their boards if either of the components is populated?!

Thank you so much for your efforts, Arcade King. Always loved that distinctive boom sound and man was I disappointed when I got the bootleg Board. After reading your reply and having a second look at the original and bootleg board pics of my last post, I can now see the difference: The LS7400 is a 14 Pin DIL while the MSM5205 appears to be a 18 Pin DIL. So there is probably no option for an easy fit of the appropriate parts. Bummer.

It seems that both of the boards do show an empty spot for an IC but where the original has a 18 Pin DIL fitted the bootleg shows a 14 Pin LS7400 at that location.

Just had a look on dozens of PCBs online, and it turns out that all bootlegs do have the 00 where all of the originals do have the 5205 instead. K1 is not populated on either of the boards. I do not feel comfortable on changing things in a way that's not reversible. There may be a way using a socket and some wiring, but I'm probably too lazy for that :-)

Better look out for an original, a cheap defective one would come in handy.

That is a ceramic resonator, you would need to know the frequency. I haven’t seen that package, but the symbol is.

They aren’t a cheap part when talking mass production, so finding a way to omit it would be a bonus.

You might be on the right track. They could have got a close clock from somewhere else on the board.

edit, so they give you the frequency in the schematic... Not familiar, but you know what to look for.

Crystal of correct frequency will also do.

Can’t say for sure it’ll solve you’re issue, but to bet either way, I would say yes.

Thread resurrection.

I have just obtained a moon patrol bootleg and want to see if I can mod the soundboard to get the original explosion effect.

Have just ordered the chip and crystal and when they arrive I'll see if I can figure out how to do it.

Thread resurrection....

Hey good luck with the mod. :)

Make sure the ROM you are using has the sound clip inside and the code to use the OKI chip. You may need to change out the ROMs on the sound board with ones programmed with Williams code.

I assumed that the rom would be the same on the bootleg but have just checked to make sure.And It's identical.

Anyway I have figured what I'm going to do.

First I'll remove the 74LS00 and fit the XTAL2 in it's place but then the 5205 will go on a seperate board so I can run the wires to points on the sound board that they need to go to.

I'll give it a test and if it doesn't work I'll see about removing any part of the bootleg sound that might be interfering.

Looking at the board I can see that the components surrounding the XTAL2 are present so I'm hoping just fitting that and the 5205 will bring the correct sound back.

Fitted the parts but so far nothing.Because I have removed the LS00 I'm now getting no explosion sound.

When I get time I'll recheck the wiring and start probing to see if I can see what is happening.

I have done this mod in a way I can remove it and go back to the original setup but hopefully I'll get it working.

Go two wires mixed up.Sorted that but still no sound for the explosion.

Have probed the chip and I'm seeing no data on pins 1-3 which I think should be data in.

tried burning the original Williams roms for the CPU board as the code is different from this bootleg but still no difference.

One thing that is strange is I have a signal from the crystal on pin 17 but nothing on pin 16.Is this normal?

Just realised I have been looking at this the wrong way.

I was thinking that pin 1-3 were the inputs for the 5205 and it output on pins 4-7 but now I realise it's the other way round with pins 1-3 setting the frequency the 5205 works at.

Checking 4-7 I'm seeing data so either the chip is faulty,the missing signal on pin 16 (oscillator input from the crystal) or I'm missing something.

Also testing today sometimes I could randomly hear a faint explosion sound but it's too faint to tell if it's the correct one.

Hi, I'm a newbie.

I am also interested in your moon patrol sound upgrade. I have a bootleg moon patrol pcb, too.

Game play is satisfactory, but the sound part was little disappointing.

Because I felt different from the expansion sound effect of Moon patrol when I was young.

Like Gonzo said:

"It looks that bit of the boards do show an empty spot for an IC but where the original has a 18 Pin DIL fitted the bootleg shows a 14 Pin LS7400 at that location."

How to swap the present LS7400 for a msm5205? I wish you could show me a photo or a picture.

I hope the experiment will succeed and want to know the processes and results.

Good luck.

This is on hold for a while as I've lost all sound from my moon patrol.

I think it's the sound amp so am waiting for replacements but they are coming from China so it's going to be a while.

If I ever get this working I will post pictures and info on how to do it.

Got the new amp fitted and got the sound back but still can't seem to get this to work.

Someone with an original moon patrol checked the crystal and got a signal on both sides where I'm still only getting a signal on pin 17.

I don't think it's the crystal at fault as I get a signal on pin 17 even if I change the orientation of the crystal.

You may need to adjust the capacitors at C33 and C34 - they are connected to between the chip and crystal and ground and C25. The datasheet for the 5205 shows them to be 220pf each, but the value will vary depending on the ceramic oscillator brand you use. It doesn't show to use a cap like the one at C25 so try to remove that one first if the other 2 are 220pf already.

I'm assuming you're using a 384KHz ceramic oscillator and not a crystal. If you're using a crystal then you'll need to drop those caps way down in value.

I am using 393 KHz ceramic oscillator as that was the nearest value I could find.

This board is missing C25 but since I'm getting a clear signal on pin 17 I'm not worried about that.

Anyway I had a brainwave and replaced the bootleg roms with the original moon patrol romset since maybe the program was adapted for the 74LS00 instead of using the 5205 and now I'm getting some sound of explosions.

It's intermittent,quiet and doesn't sound right so next I'm going to replace the 358 to see if that improves things.

Bit of a delay while I waited for more 5205 chips sine I seem to have damaged the ones I was testing with-wasn't getting a signal on pin 17 from the oscillator.

Anyway new chips arrived today but work got in the way so It's after midnight here but....I think I've done it.

While troubleshooting and removing all the connections to test on a breadboard I noticed something I had missed.

Pin 14 of the 5205 connects via R5 to TR1.What I had missed was a track going from R5 to the connector that joins to the CPU board.from what I can tell pin 14 turns all the other sound FX off while an explosion is happening but with the signal also coming from the CPU board things were getting mixed up.

I pulled one end of the resistor up and connected it directly to pin 14 of the 5205 so the signal from the CPU board was no longer interfering and I then got the correct explosion sound.

The mod is a mess at the moment from all my troubleshooting but when I get the chance I will detail how to do it.

OK.A rough guide on how to do this mod.

You need:5205 speech chip,A 384 Khz ceramic oscillator (I used a 393 Khz as this was the closest I could obtain),veroboard,the moon patrol schematic for reference and some wire.

First you need to remove the 74LS00 as this generated the poor explosion sound so it's not needed.

Then set the veroboard up so that the middle tracks are cut so you can fit an 18 pin socket for the 5205.Then you can run wires from this to the moon patrol sound board.

Note I also connected pins 9 and 12.Pin 9 will be connected to ground and pin 12 needs grounding also.

Pins 1,2 and 3 of the 5205 need connecting to three holes that connect them to R18,R17 and R16 respectively.

There are two sets of three holes in this location.You want the holes nearest to R18.

Next to these holes are two capacitors,C34 and C33.Pin 17 needs connecting to C33 and pin 16 is connected to C34.Connect to the capacitor legs closest to where XTAL 2 is marked.

The ceramic oscillator goes in the XTAL 2 spot.

Next notice there is a place for an 18 pin chip next to where you removed the 74LS00.We are going to use this to connect pin 18 (5V) and pin 10 (sound out)

So pin 18 if the 5205 goes into the 18th hole of the empty socket and pin 10 of the 5205 goes into the 10th hole of the empty socket.

Connect pin 9 (GND) of the 5205 to the ground line at the edge of the board and connect pin 15 to the side of R27 nearest to where the 74LS00 used to be.

Next we need to connect pin 4-7 to pins 3-6 of the chip at 2L (74LS173).Pin 4 of the 5205 goes to pin 6 of the 74LS173,pin 5 of the 5205 goes to pin 5 of the 74LS173,pin 6 of the 5205 goes to pin 4 and pin 7 goes to pin 3

Now the last bit is the part that caught me out.

Pin 14 of the 5205 needs to be connected to the side of R5 nearest to C39 BUT you must first remove that leg of the resistor from the PCB to disconnect if from the signal coming from the CPU board.

Now your mod is finished.

The explosion sound is a little quiet on my board so I'm going to look into changing the resistor that it goes through to see if I can make it louder.

So even though on the schematic R15 is 22K on my board it was 2.2K

replaced with a 1K resistor and now the explosions are nice and loud.

Hi Lurch666,

Congratulations! Your experiment worked! I'm going to do it like your mod.

Is it impossible to replace the jump wires with universal board with pins and socket at 74LS00 location?

I'm going to put this board in order and make it simple. If you could post full picture of the Moon patrol pcb, it would be very helpful for me to create mod.

I'll post it as soon as I finish my mod.

Thank you.

From what I could see the connections of the 74LS00 and the empty slot next to it were connected in a different way or not at all.You might be able to find connections to the correct components to fit the 5205 but for simplicity I just connected to the components as specified in the schematic.

I have now redone this mod with all the connections on the underside of the sound pcb and the chip is in a plastic case so it sits between the sound board and the cpu board so it looks a lot neater.