TECH HELP: scramble sound or lack of!

[John Bennett]

[ukvac] TECH HELP: scramble sound or lack of!

just a quick technical question for the brainier amongst us, i have a stack of stern/konami scramble pcb`s all these have one thing in common..no sound , does anyone know if there is a particular component that causes these failures? , as i would like to try to fix them, i know its not the AY sound chips as i`ve replaced these from known working boards , but to no avail, can anyone helpor fix(£) these boards

thanks guys



DATA Imported from archives: originally posted by mark coldwell (llantwit@llantwit.screaming.net)

 

[John Bennett]

Re: [ukvac] TECH HELP: scramble sound or lack of!
I had exactly the same problem it turned out my psu was not supplying -5v
the wire had been cut in the loom
everything else worked ok

other things to checkwould be sound volume pot on pcb
and check pinouts

Stern: SCRAMBLE - two board version (L-1200-1 and L-1200-2)

A (down) B (up)
--------------------------------------------------
-5V 1 +12V
SPKR1 2 SPKR2
2P fire 1 3 2P fire 2
2P left 4 2P right
1P start 5 2P start
1P fire 2 6 2P up
1P fire 1 7 service
1P right 8 1P left
1P up 9 2P down
Coin 1 10 Coin 2
1P down 11 Coin counter
NC 12 NC
Green 13 Blue
Red 14 Sync (composite negative)
15
GND 16 GND
GND 17 GND
+5V 18 +5V



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DATA Imported from archives: originally posted by markgwilliams (markgwilliams@ntlworld.com)

 

[guddler]

RE: [ukvac] TECH HELP: scramble sound or lack of!
Lack of -5v (or is it +12v can't remember) normally does it - almost
definately if ALL your copies (just how many do you have!) are all the same,
it's almost bound to be the PSU.

Prolly -5v i think...

Guddler

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