Track and field PCB Sound issue...

higgibaby

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I have just started my T&F restoration, but when I received the cab, the sound was nuts...it just squeals and sounds like a jet when they run...looking at the board with a multimeter, I noticed this lower large chip isn't showing any readings where the others are coming in at around 5v...what can I do? Help...

ZA7l9q1l.jpg

QOoN1bfl.jpg
 
sound uses +12 volt. ots unregulated so dont be concerned if you detect +10v through +14v or even higher
so you should be tracing that from the power supply through the connectors into the power supply and see where it stops is what i'd do first
 
if they're hearing what sounds like squeals and a jet, then the amplifier isn't at fault. that's working.

I don't know what logic parts fail in the sound section on these. a lot of them I've seen just didn't have sound at all. the machine that happens to be in my jurisdiction works fine, so I haven't needed to explore this. :p
 
I'm pretty sure that chip in the first photo is the VLM5030 speech synthesiser chip and would not be the primary cause.

Your problem is most likely with the other larger chip nearest the ribbon connector ( the z80 CPU ), static ram, the EPROM or ttl support logic ( highly likely failed Fujitsu branded part(s) )

I repaired the sound section of a Hyper Sports recently which had multiple failures ( bad CPU, Fujitsus , speech synth and ram). Symptoms like yours are quite common on these
boards.

Have you at least tried reseating the two EPROMs on the top board ?
 
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I'm pretty sure that chip in the first photo is the VLM5030 speech synthesiser chip and would not be the primary cause.

Your problem is most likely with the other larger chip nearest the ribbon connector ( the z80 CPU ), static ram, the EPROM or ttl support logic ( highly likely failed Fujitsu branded part(s) )

I repaired the sound section of a Hyper Sports recently which had multiple failures ( bad CPU, Fujitsus , speech synth and ram). Symptoms like yours are quite common on these
boards.

Have you at least tried reseating the two EPROMs on the top board ?

Thank you for the information! Im not incredibly technically minded (not ashamed to admit that...lol) But from all the posts I used for reference, I saw reseating those chips may help, and I did do that, but I still got the same prob...Now I didn't clean them, that would be my next step...I appreciate the info though. Like I mentioned, I did take the meter to that lower soldered chip in the first pic and got no readings at all...
 
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