Mike Doyle
Well-known member
I just fixed the sound this evening and thought I'd post the details to help anyone else down the road.
When I initially brought the game home, the audio was fine but there was no video in game play mode, although test mode would display fine. I was also unable to advance in test mode.
Rolling the dice on eBay, I bought a non-working but very clean Burgertime boardset for $35 bucks. Initial test with it had a badly out of sync picture and no sound. By combining halves of my old board and the eBay board, I ended up with a nicely playing, but silent game.
I recapped the sound section and swapped the sound amp from my working board, but still got nothing but the loud hum. Before I broke out the HP logic analyzer, I decided to socket and swap the Mostek 24 pin chip next to the amp. From the factory, pin 24 and pin 19 are joined by a short length of wire. One version had the wire on the solder side and the other boardset had it on the chip legs.
After pulling the single Mostek from each board and installing 24 pin dual wipe sockets, I added the jumper from pin 24 and 19, installed the chip from my working audio board in the socket of the eBay board and was soon playing a nice and loud Burgertime for the first time since it had come home.
Between these boards, there were also two revisions of the heat sink for the amp, I opted for the larger version along with a dose of heatsink compound to replace the dried out stuff.
When I initially brought the game home, the audio was fine but there was no video in game play mode, although test mode would display fine. I was also unable to advance in test mode.
Rolling the dice on eBay, I bought a non-working but very clean Burgertime boardset for $35 bucks. Initial test with it had a badly out of sync picture and no sound. By combining halves of my old board and the eBay board, I ended up with a nicely playing, but silent game.
I recapped the sound section and swapped the sound amp from my working board, but still got nothing but the loud hum. Before I broke out the HP logic analyzer, I decided to socket and swap the Mostek 24 pin chip next to the amp. From the factory, pin 24 and pin 19 are joined by a short length of wire. One version had the wire on the solder side and the other boardset had it on the chip legs.
After pulling the single Mostek from each board and installing 24 pin dual wipe sockets, I added the jumper from pin 24 and 19, installed the chip from my working audio board in the socket of the eBay board and was soon playing a nice and loud Burgertime for the first time since it had come home.
Between these boards, there were also two revisions of the heat sink for the amp, I opted for the larger version along with a dose of heatsink compound to replace the dried out stuff.
