Monstermug
Active member
This was one of the other boards donated to me by Bonehead to scrap. Very kind of him!
Unfortunately it's another one of those game genres that doesn't get any loving and nobody can be bothered to repair!
Plugging it in I got a very nasty static pulsing noise coming out the speakers although most of the sounds were there some sound channel seemed very low.
Also there was no background graphics and jail bars on the screen.
First thing to do was give the game a nice wash as it was also spider infested.
Much more presentable now and looks like it might be worth fixing after all.
First thing to do was to check mame to see what rom chips contained the graphic code. I found that Rom 15 @ 07L was in charge of BGMAP. Removed this and verified rom. Failed instantly. Reburnt new roms and got background graphis and cured the jailbars too!
Now just the sound section to fix.
First I decided to check capacitors and found failing capacitor at CC15 and CC9. Changing these did not fix the audio issue.
Had to straighten out this op amp too although that was purely for cosmetic reasons.
Decided to just shotgun replace all capacitors that showed higher than normal ESR.
Still problem wasn't fixed. I didn't really expected it to anyway.
Saw a resistor had broken off at R13 but I don't think this effected the circuit anyway as this wasn't populated on most F1 dreams anyway. So I just ignored it.
Now I had decided to breakout Philmurr's audio probe! Fantastic bit of kit.
Audio Amp was a HA13001. Pins 3 are inputs and pins 7 and 12 are outputs. The noise was apparent on the inputs as well as the outputs.
Tracing back to the op amps shows everything is working fine. Something else was causing static interference which would go away on different screens!
Probing around further I found that leg 1 of Intel D8751H-8 was bent over not making contact!.
Looks like someone had previously tried to reseat chips and bent this one putting it back in!
Bent it back and now static sound went away and sounds are now all present and perfect!
Unfortunately it's another one of those game genres that doesn't get any loving and nobody can be bothered to repair!
Plugging it in I got a very nasty static pulsing noise coming out the speakers although most of the sounds were there some sound channel seemed very low.
Also there was no background graphics and jail bars on the screen.
First thing to do was give the game a nice wash as it was also spider infested.
Much more presentable now and looks like it might be worth fixing after all.
First thing to do was to check mame to see what rom chips contained the graphic code. I found that Rom 15 @ 07L was in charge of BGMAP. Removed this and verified rom. Failed instantly. Reburnt new roms and got background graphis and cured the jailbars too!
Now just the sound section to fix.
First I decided to check capacitors and found failing capacitor at CC15 and CC9. Changing these did not fix the audio issue.
Had to straighten out this op amp too although that was purely for cosmetic reasons.
Decided to just shotgun replace all capacitors that showed higher than normal ESR.
Still problem wasn't fixed. I didn't really expected it to anyway.
Saw a resistor had broken off at R13 but I don't think this effected the circuit anyway as this wasn't populated on most F1 dreams anyway. So I just ignored it.
Now I had decided to breakout Philmurr's audio probe! Fantastic bit of kit.
Audio Amp was a HA13001. Pins 3 are inputs and pins 7 and 12 are outputs. The noise was apparent on the inputs as well as the outputs.
Tracing back to the op amps shows everything is working fine. Something else was causing static interference which would go away on different screens!
Probing around further I found that leg 1 of Intel D8751H-8 was bent over not making contact!.
Looks like someone had previously tried to reseat chips and bent this one putting it back in!
Bent it back and now static sound went away and sounds are now all present and perfect!
I was a big fan of this kind of thing back in the day. The racetrack maps are very cleverly designed so that the smallest are in the middle, and the largest ones are on the outside of one single large tilemap. There are a few collision points where you can pop out of the current track and end up on a completely different one
