Requesting Sound help (very loud buzzing) on NBA Hangtime pcb

[chairhome]

Hi everyone,
I'm a noob to the arcade scene and this forum.

I recently received a NBA Hangtime PCB and it looks to be in good shape.  The previous owner told me it should work perfectly, and I believe him because he's been very helpful.  The problem is that when I boot up the game, there's a very loud screeching/buzzing noise.  After the ROM check, it checks the sound ROMs, and the noise changes to a slightly lower (but still loud) buzzing.  It continues throughout the game.  I can hear sounds when they're supposed to occur, but they don't sound exactly right, they sound muffled by the buzzing.  Everything else seems fine

 I am running it off of a TMNT cabinet, and I'm pretty sure the wiring is correct.  The sound ROMs seem to be seated right, and the amp looks brand new.  Any ideas?  Sorry to bother everyone with this, or if this is the wrong part of the forum to be posting, but please let me know if you have any ideas.  Thanks in advance.

[TravistyOJ]

Not really sure about NBA Hangtime, but does it have a seperate sound board (I know NBA Jam does).  There should be a pot (knob) to control the volume, makes sure there isnt a loose connection to that.

[APFelon]

Nope, no seperate sound board (at least on mine).

Have you raised and lowered the volume at all, and does the hum get quieter and louder?

Have you tried a different speaker? (I think the TMNT cab is mono?? if I remember correctly).

Is the wiring to the speaker correct?

Are you near a transmitter tower of some sort? Or by any appliance that could give off interferance?

Do you have another JAMMA board you could toss in there to see if the problem stays?

Good luck

APf

[chairhome]

Thanks for the replies...

It is mono, but according to KLOV, Hangtime is also mono.  The sound is not on a separate board, there is only one pcb.  I've tried the harness on 4 different games, so I'm pretty sure its not the harness/wiring.  I haven't tried a different speaker yet, but since the other games work, 'm pretty sure its not the speaker.  And I haven't really tried messing with the volume, I'll give that a try.  Thanks again.

[chairhome]

Still having problems... I'm thinking that some of the traces might've been broken during shipping (my brother, who received the package at my house, said that the board looked like it was bending a little), and now there might be a voltage problem to the speakers.  The ROMs all check out during the ROM test, so this is the only thing I can guess might be wrong with it.

[bobbyconover]

Is the -5v hooked up to the edge connector? Midway boards from around that time required it, if I remember correctly, but most typical JAMMA harnesses don't include it since it's rarely required by JAMMA PCBs.  I had a Maximum Hangtime PCB that had the exact same problem as yours, and I got the same kind of advice from everyone I asked about it until finally solving it by wiring in the -5v. I imagine that's the case here as well!

[chairhome]

Its not hooked up!  Thank you, I haven't tried it yet, but I have a very good feeling about this.  I'll post again once I try.  Thank you so much.

[chairhome]

It works!  Thank you so much, I owe you.

[bobbyconover]

Awesome, glad it worked out!