Hi I just picked up a cheap tascam mm1 in good condition but on power up the first 4 channels level indicators are all lit , none of the mute switches light , but all the digital section seems to work fine. The PSU is putting out +/-13v little high should be +/-10 , there's 2 power transistors and a 7805 regulator(which seems to be ok) not check the power transistors yet, but don't have schematics just owners manual. Any one had similar issues , it's also not outputting any audio .also on power up all the green led light up very briefly on every channel then extinguish.Just leaving all level indicators lit on first 4 channels. Turns out there was no negative power to the bus rail, the main on off switch turns off /on the +/- voltages the negative side was N.O. replaced switch all working
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