Viewing Issue Advanced Details
ID Category [?] Severity [?] Reproducibility Date Submitted Last Update
07910 Sound Minor Always Mar 20, 2021, 10:02 Apr 12, 2021, 04:52
Tester sasuke View Status Public Platform MAME (Official Binary)
Assigned To Resolution Open OS Windows 10 (64-bit)
Status [?] Confirmed Driver marineb.cpp
Version 0.229 Fixed in Version Build 64-bit
Fixed in Git Commit Github Pull Request #
Summary 07910: bcruzm12: Lack of explosion sound.
Description All sounds when a player or enemy explodes do not sound.


PCB: (I'm Not sure why there is a difference in the loudness of the explosion between the both PCBs.)

Steps To Reproduce
Additional Information
Github Commit
Flags Verified with Original
Regression Version
Affected Sets / Systems bcruzm12
Attached Files
jpg file icon ETC-0116_BHN1.jpg (684,364 bytes) Mar 20, 2021, 15:59 Uploaded by jkburks
Battle Cruiser M-12 PCB Front
jpg file icon ETC-0116_BHN2.jpg (695,296 bytes) Mar 20, 2021, 15:59 Uploaded by jkburks
Battle Cruiser M-12 PCB back
jpg file icon D66CgHJUYAAcNbw.jpg (2,029,303 bytes) Mar 20, 2021, 16:31 Uploaded by jkburks
Battle Cruiser M-12 PCB Front Angle
There are no relationship linked to this issue.
User avatar
Mar 20, 2021, 12:44
edited on: Mar 20, 2021, 12:45
I'd bet it is discrete sound.
No manual seems to have been scanned to examine - so we'd need some very good pictures of the PCB to determine what's up.
User avatar
Mar 20, 2021, 16:02
edited on: Mar 20, 2021, 16:35
These two PCB photos are the best I could find. I'm not sure if the front photo is high enough resolution to get positive ID on the resistor stripe patterns.
The game manual shows up on auction sites from time to time, but I have only seen low resolution photos of the cover, never the pages or schematics.
Edit - found another photo of the PCB front and uploaded it. For some reason it is not showing a preview, so just click the link below the second PCB photo.
User avatar
Apr 12, 2021, 01:06
Can anyone find a better front pcb pic, with readable chip numbers to the right of the GI AY-3-8912's?
There's another sound missing from emulation, it's the low pitched "atmospheric" noise that plays constantly when the machine is switched on. Possibly some sort of leakthru from the explosion circuit?

After some digging:
I believe the first ay's output port control the background warble / atmospheric noise
and the first output port on the second ay triggers the explosion. 2 for enemies, 6 for the player's ship (louder)

regarding the explosion volume differences in the reference videos above. It's simple - the first one is played using a little speaker or tv's speaker (out of cabinet) and the other 2 videos are played on an arcade cabinet, which houses a nicely-sized speaker.
User avatar
Apr 12, 2021, 04:52
To my eyes, the four ICs to the right of the first AY-3-8912 are SNALS74N (4D), SN74LS161AN (3D), MC14006B (2D) and MC14070B (1D). The last two of those, with a bunch of discrete components surrounding them, suggest some variant of the CMOS LFSR+astable white noise generator Space Invaders uses for explosions.