new outrun arcade cabinet - humming noise from the speakers

[fluxgold]

hi there, i got a outrun minimcabinet in awsome condition , plays great
i just have 2 problems :

i have a humming noise from both speakers - if i disconnect the cable to the speakers from the soundboard the noise is still there .... all game sounds sounds good anyway ... but the noise is bad ..... you know how i can fix it ?

then the monitor scales the sizes randomly after the arcade is about 20 minutes turned on .... just minimal changes of the size.... at the early start its not  changing. what could be the problem ?

the outrun was standing at a safe place for many many years not turned on .... do i have look at something  first after that long inactivity ? i read about battery suicide , but on my pcb there is no of the warned batteries. i have a rev b. board maybe on that it was still fixed !?!

greets
fluxgold

[iankellogg]

Only the outrun turbo game has the suicide battery.

When you say you unplug the speakers? do ou mean you unplug the pcb from the amp or do you mean you actually disconnect the speakers? It could be as simple as new caps or could be some kind of interference with the monitor.