Older Bose Cinemate home theater system failure

[Keshenatech1]

I have an older Bose Cinemate home theater audio system. It only has 2 RCA inputs, no optical connector. The interface module is also what communicates with the IR remote control. The interface module and speakers are connected with DB9 serial cable type connectors. When the unit is in standby, a red LED lights up on the interface, and a green one when it is turned on. Or I should say it used to. I went to turn mine on the other day and no LED's were on, and there is no response to the remote. So I took it apart and verified the power supply seems to be working. Transformer has continuity on primary and secondary side and fuses are good. There's a 3 pin regulator in the upper left corner of the main board and I measure 5V in and 3.3V out. (Center pin is ground) I also measure around 28V across the main filter cap on the main board and also on the connector board. So my conclusion is either something died in the digital section and it's not repairable or something failed in the interface section. I can buy a replacement (non-returnable) interface online but I was wondering if anyone out there has any experience with these units and can tell me if there's any way to determine if the problem is on the main board or interface unit? I'm attaching several pictures of it taken apart. Thanks

[Keshenatech1]

Re: Older Bose Cinemate home theater system failure

Well I decided to take apart the interface unit and it's directly wired, Red and Green LED's, IR, audio jacks directly connected to wiring with no components in-between. And I have continuity from every one of the 9 pins to the wires on the inside. So I answered my first question, problem is definitely in the main board. So new question, is there anything that can be done to troubleshoot and repair something like this when the digital section dies, or is it junk? Usually I see a power supply failure when something like this happens but that seems to be good. Also measured ESR on all the SMD capacitors and they're within a good normal range.
Thanks again