Outrun help

[Gamesmonkey]

Hi all,
I have an Outrun pcb with this sort of screen corruption.

So I grabbed the mem test roms and burned them and put them in and got this.

I believe these are the RAM chips at the locations IC20, IC21, IC38, IC39?
So my question is where can I get some TMM2115BP-10 ram or what would be a good alternative to these?

Thanks for the help

 

[AlxUnderBase]

Cheers sir !

TMM2115BP-10 = ?

TMM2115BP-15 = MB8416A-15L-SK ( http://www.buy-transistors.com/ics/tmm2115bp-15.html )

or for US customers : https://www.arcadeshop.com/i/1476/mb8416a-15l-sk-tmm2115bp-15-sram.htm

Maybe this can helps you better in your journey

 

[Gamesmonkey]

Many thanks
I have ordered some MB8416A-15L-SK

Cheers Justin

 

[KaPH33n]

-15L is slower than -10 by 50 nanoseconds... if it works it works though.

 

[Apocalypse]

While it could be both RAMs are bad, seing they have in common to be on the same data bus (LSB) it's possible you have a faulty logic chip on one of the busses.

 

[Gamesmonkey]

Many thanks for all of the help.
I will let you all know how I get on when the RAM arrives.
Cheers Justin

 

[Gamesmonkey]

Hi
To follow this up the RAM was bad so I replaced all four RAMS with sockets and now the game runs fine.
However, there is a new problem of no sound. when first powering up the board you can hear a very rough scratchy sound and then nothing.

So far I have checked the 315-5218 Sega chip and reflowed it.
Looking for help and suggestions on what to check next, please.

Cheers Justin

 

[Apocalypse]

Could also be a bad sound RAM or sample RAMs.

 

[Gamesmonkey]

Hi
Ok I have replaced the RAMs in the sound section and now have partial sound.
Is my 315-5218 dead?
Distorted sound

Cheers Justin

 

[Apocalypse]

Hi
Ok I have replaced the RAMs in the sound section and now have partial sound.
Is my 315-5218 dead?
Distorted sound

Cheers Justin

All 3 RAMs? Were they all tested bad?
Just watched your video, you have floating lines. Check that you didn't sever traces while installing sockets for the RAMs.

 

[Gamesmonkey]

Many thanks, Apocalypse for the advice.
After hunting around I found a bad LS173 replacing this restored the sound completely.

Cheers Justin

 

[Gamesmonkey]

Aaaaaahhhhh

I thought I was done with this Outrun board set, but now have developed a fault where the road stops bending??

Anybody have any ideas I am thinking of logic in the road section?

Cheers Justin

 

[Apocalypse]

Aaaaaahhhhh

Sorry to say but OutRun is one of the least reliable piece of hardware I know of. It's not rare I have to fix triple or quadruple faults on the same boardset, with new faults appearing during the repair...
BUT if you replace preventively all those "shiny" RAMs and fujitsu and SGS TTL chips it becomes rock solid.

Anybody have any ideas I am thinking of logic in the road section?

Probably yes.