I've had a very similar problem with my recently-acquired Black Hole. Background sound cuts in and out, while the sound effects work consistently. I'm in the middle of attempting to fix it at the moment. I would strongly suggest re-pinning the connectors. These games use edge connectors (as opposed to the trifurcon type) which are available at GPE: https://www.greatplainselectronics.com/products.asp?cat=77

I highly recommend getting new connector housings for any of the connectors you're planning on replacing. The IDC pins *can* be extracted, but it's tricky. Sometimes they come right out, other times it's 5+ minutes twisting, pulling, cussing, etc until it comes out. It's worth the $1-$1.50 per housing to avoid the headaches, in my opinion. Make sure to buy connector pins for both wire gauges too--most will be 22-26 gauge, but there are some thicker wires that will need the 18-20 gauge pins. Pretty much everything you'll need should be at GPE.

It probably wouldn't hurt to change out those electrolytic caps on the sound board as well (which are also available at GPE). I should also add that as I've been re-pinning the connectors, i found the wire that carries 'Sound Line 1' from the driver board to the sound board looked like it had been pulled out and poorly reinstalled in the idc connector, so I'm hoping that's what the problem was. Still not familiar enough with this system to know for sure, but it seems plausible enough...

Good luck!

I fixed/upgraded all the pop bumper boards on mine. Clay's guide has a run-down of all the recommended upgrades/parts suggested to fix em up. Might be $10-15 worth of caps, resistors, etc to do up all the pop bumper boards (Black Hole has 6, not sure about Haunted House), or $20 or so apiece for new replacement boards. Guess it depends what your time is worth to you. I would definitely stock up on edge connector pins/housings in any case, the system 80 games are notorious for connector issues...

Not sure what the advantage is of the split in the connector pins...the bifurcated pins are the type used on the double-sided interconnect harness between the CPU and driver board and for the black connector at the bottom of the driver board. I think Big Daddy Enterprises is the only place that carries them at the moment...but not only do they only sell them by the hundred, they also have a high minimum order threshold.

Otherwise, the pins i linked to will work fine for the rest of the edge connectors, as far as i know. Just remember to get both wire gauge sizes (and plenty of housings for the connectors you intend to replace). Have you already done the ground mods on your system 80 games?