The dbx TR1616 is no longer available and no longer repairable, due to lack of parts.  There are a number of replacement options that utilize other HARMAN Professional products.  The TR1616 is 16 Balanced microphone/Line level inputs with Phantom Power and 16 Balanced Line Level outputs transcoded to BLU link. BLU Link is a proprietary audio transport protocol developed by HARMAN Professional for the Soundweb London line of Digital Signal Processors [DSP's].  It has been adopted across several of the HARMAN Professional brands such as BSS Audio, Crown amplifiers, Soundcraft mixers and dbx processors.  

Here are some possible replacements:

Soundcraft

There are BLU link option cards available for both the Soundcraft Si and Soundcraft Vi series of mixing consoles.  These option cards offer a 32x32 interface to the BLU link bus.  

Soundcraft Vi Blulink card- https://www.soundcraft.com/en-US/products/vi-option-cards
Soundcraft Si Blulink card- https://bssaudio.com/en/products/blu-si

BSS Audio

Option 1

[1] BLU-120 - Soundweb London expansion chassis

with [4] BLUCARDIN Mic/Line Input cards

[1] BLU-120 - Soundweb London expansion chassis

with [4] BLUCARDOUT Line output cards

Option 2

[2] BLU-BiB - Soundweb London Break in Box - 8 Balanced Mic/Line input expander

[2] BLU-BoB - Soundweb London Break out Box - 8 Balanced Line output expander

Note: The Soundweb London devices do not have XLR connectors, they have screw terminals.  You will need to remove the XLR connectors and use the screw terminals or get an XLR patch plate that can be wired to the screw terminal connectors of the Soundweb London.  These can be purchased from any of the online music equipment retail vendors.