Orange Universal Ladybug board, Low audio (SOLVED)

[Dionea]

Hi all, hope somebody has ideas on the following:

The Issue:
Recently acquired an orange Ladybug board (the one-board version that came after the original two-board release). Game plays fine, no video issues. Audio is present, but very quiet. The volume pot on the board has no effect.

Work Done:

• Tested with two different JAMMA adapters:
  • One with built-in amplifier (not required for Ladybug)
  • One without amplifier
  → Same issue on both setups
• Swapped the HA1388 amplifier IC → no effect

Planned Work:

• Replace all electrolytic capacitors (awaiting delivery)

Details:
From what I’ve read, orange Ladybug boards are often reported to have audio issues. Many listings mention either very soft sound or no sound at all.
This board also shows a lot of factory rework (extra solder joints, cut traces). It looks original since I’ve noticed exactly the same on other orange boards being sold.

Question:
Has anyone here had similar experiences with the orange Ladybug boards and their audio problems?

 

[nem]

I recapped mine. Perfectly loud. Try that first.

You likely noticed, but you can replace the axial capacitors with radial lead ones. There are alternative solder holes available.

Picture of my board.

Mine also has the freeplay and highscore save enabling roms from Gadgetfreak.

 

[Dionea]

Thanks! Yeah, I noticed the possibility for radial caps but was able to get the axial ones. I will recap and then see.

Mine has quite some rework done, with traces cut and sometimes different components. It seems factory done (I think to fix the coin input issue), as I've seen exactly the same applied changes on multiple boards. Don't think that is related to the sound issue though.

 

[Ape Cosplay]

Thanks! Yeah, I noticed the possibility for radial caps but was able to get the axial ones. I will recap and then see.

Not necessarily a bad choice. Axial capacitors with their lower profile have a lot less chance of being ripped off the board.

 

[Dionea]

I replaced all electrolytics on the board, no difference.

It looks like there are at least two board revisions with factory rework in the audio and coin sections (but same mentioned 1806-II board ID). At location T1 you can tell them apart on the component side:

• Factory-modified revision → edge side of the chip has two ceramic caps + one electrolytic
• Unmodified revision → three ceramic caps

What’s interesting is that every example I have seen reported with audio issues has been one of the modified revisions (there is one on eBay right now that matches this pattern).

This makes me wonder if those boards required a slightly different harness or output configuration, and that is why the audio problems show up when using a JAMMA adapter?

 

[Dionea]

The orange single-board version uses an HA1388 (12-pin) audio amp, while the two-board version (and most other early Universal boards) uses an MB3730 (7-pin).

All the Ladybug JAMMA adapters I’ve come across have pin L wired to SP+ and pin M to ground (as SP–). I’m starting to think this might be the issue, since the HA1388 may not tolerate having one of its outputs tied directly to ground.

Could anyone with an orange board confirm what their JAMMA speaker outputs look like?

 

[Dionea]

For future reference if anyone is having the same issue and was looking for a solution:

The ground on pin M turned out to be exactly the issue. On the Ladybug double-board version with the MB3730 this doesn’t cause a problem, but on the orange single-board version it means pin 7 of the HA1388 is effectively pulled straight to ground, killing all audio.

I tested it with a quick jumper wire, confirming my theory, and then fixed it "properly" by scratching the ground trace on the JAMMA adapter.

So basically, most of the commonly used Mr. Do!/Ladybug JAMMA adapters have this same flaw with (single) orange boards, and audio won’t work unless you make this modification.