Alpine 3566 problems powering up and un-muting

LATCH problem, amp will mostly power up with just B+ and ground connected - it'll draw 2.6A and the status/power LEDs go green. +-22vDC and +-28vDC rails referencing secondary ground, but then referencing amp ground the rails are offset by 12v meaning secondary voltages are not well centered only when RCAs are disconnected though. 5M Ohms between RCA shields, non-bridging terminals and B- indicating a floating condition.

Amp passes barely a sound indicating possible muting issue.

Starting with LATCH problem, REM doesn't do anything. Taking a look at IC703, Q7027/Q728 now...
IC703 I've never seen one of these before. Looks sort of like a resistor network. It controls mute and is also connected to remote. I dont know if those are prone to failure? Can they be replaced? Its a 35423W01

Google image:

Signal source is grounded, but just to be certain I ran only RCAs to 3/4 and momentarily grounded 3/4 RCA shields with a lead. No change in output (Severely muted still)
I may be stuck on IC703 unless there are any other areas to look here. Looks like LATCH issue bleeding into muting issue?
I replaced Q728 a DTC114ES, which honestly was measuring the same off the board as a new unit - and LATCH started working correctly with REM. Muting circuit also started working correctly. Amongst other things like leaky caps and cleaning; this amp is on its way to being fixed