(Topic ID: 212764)

No Sound from Data East Sound Board

By Opiate

4 years ago



Topic Stats

  • 7 posts
  • 4 Pinsiders participating
  • Latest reply 9 months ago by SmiggleMeThis
  • Topic is favorited by 3 Pinsiders

You

Linked Games

#1 4 years ago

Hi there!

Been trying to get this sound board going. All I get is a kind of air/static sound from the speakers that can be made softer and louder with the volume potentiometer.
I believe the board was pulled from a LW3 and I'm fitting it onto a star wars. I have burned the right EPROM sizes for U17 and U21 (27C4001 and 27C2001) and adjusted jumpers W6 to W7, also have burned a 27C256 for the holder at U7.

I have tried shorting the volume pot to see if that was a problem but so far none of the speaker tests or the boot up sound plays.

I'm starting to think it may be a bad chip, though I don't know what I am to check for with a logic probe (or a pair of headphones?).

Anybody got any ideas?

Thanks!
Ben

#2 4 years ago

Check your voltages to the sound board.
I had similar problem when saw that +5v is lower.
But I cannot remember if it need to have and +12v separate.

#3 4 years ago

Also measure the -12v on the sound board.

#4 4 years ago

I've measured the voltages and they are all as they should be.

I've been tracing the fault from U26 (which is the closest point to where all the amps converge) and managed to get a signal coming out of the speakers by shorting the clock signal pin 1 to the output pins 6 and 8. So this means the amps are fine.

I noticed pin 3 however has no signal and this is the data in. So I've followed the line to the flip flop pin 9 on U25B. Assuming the data (labelled D on the schematic) is pin 12 this also has no signal coming in.

U23 and U24 are next upstream with their output and inverse outputs on pins 7 and 9 (which should connect to pin 12 U25)

This is as far as I got with the scope. Not sure how to test if U23 and U24 are functioning correctly. Tried pins 1 on both which are labelled SHFT-LD but couldn't see much of a signal here.

#5 4 years ago

Update:

So upgraded my probing methods. I have determined that there is data on the bus but the pin 1 SHFT-LD on U23 and U24 is not having data sent from the address register connected up to the BSMT2000 (DSP) at U9, which would tell these chips which sounds to output to the DAC U26.

The reset pin on the BSMT2000 has a lot activity going to it. It seems like the this is the culprit because one can assume that the BSMT2000 never boots because its continually being reset. This could be a faulty DSP itself or something wrong with the RAM. However this reset signal may just be the function of the BSMT2000, that its reset every so often to prevent some unwanted behaviour. It would be great if someone could confirm this by probing the reset pin on their own BSMT2000.

If this is expected behaviour my next suspicion is the PAL chips.

1 month later
#6 4 years ago

Solved! Im not sure if the pal chips were broken previously but turns out having a 512kb EPROM in U7 for Star Wars meant that the board would not boot. So I swapped it down for a 256kb EPROM and it just worked!

3 years later
#7 9 months ago

Similar issue with a Simpsons... If I put a 512K Eprom in it, would the sound chips need to be upgraded or changed as well? I bought and sent a guy new game rom chips but they wouldn't work in his rottendog board, so I burnt the single rom chip from my simpsons but it doesn't have sound now on his game. Should I pull my sound rom chips and burn copies for him to work in his game or do the sound chips matter???? Not sure if they're paired to the 2 eprom chipset or if they'll work with a single eprom. Thanks ahead of time!

Promoted items from the Pinside Marketplace
From: $ 40.00
Lighting - Interactive
Professor Pinball
$ 17.50
Playfield - Plastics
Pinball Haus
$ 14.95
Playfield - Toys/Add-ons
ULEKstore
3,200 (OBO)
Machine - For Sale
Los Angeles, CA
$ 18.95
Eproms
Pinballrom
$ 12.00
Playfield - Toys/Add-ons
UpKick Pinball
$ 99.00
Playfield - Other
Arcade Upkeep

Reply

Wanna join the discussion? Please sign in to reply to this topic.

Hey there! Welcome to Pinside!

Donate to Pinside

Great to see you're enjoying Pinside! Did you know Pinside is able to run without any 3rd-party banners or ads, thanks to the support from our visitors? Please consider a donation to Pinside and get anext to your username to show for it! Or better yet, become a Pinside+ member!