It a Zenith z100 desktop computer from 1982
But the computer case is the same as the z150
I saw a service manual with the z100 and z150 using the same computer case so this must be it.

Z100 Specs:

Design
The Zenith Data Systems Z-100 is a pre-assembled version of the Heathkit H100 electronic kit.[2] In the same family, the Z-120 is an all-in-one model with self-contained monitor, and the Z-110 (called the low profile model) is similar in size to the cabinet of an IBM PC.[3] Both models have a built-in keyboard that was modeled after the IBM Selectric typewriter.[3]

Dual processors: 8085 and 8088.
Available with CP/M and Z-DOS (non-IBM compatible MS-DOS variant).
Five S-100 expansion slots.
Two 320 KB 40-track double-sided 5.25-inch floppy disk drives. Socket enabled direct plug-in of external 8-inch floppies.
2× serial ports (2661 UART), one Centronics printer port (discrete TTL chips), light pen port.
640×225 bitmap display. 8 colors (low-profile model), or monochrome upgradable to 8 greyscales (all-in-one).
Base 128 KB RAM, expandable to 192 KB on board, to 768 KB with S-100 cards. (Video RAM was paged into the 64 KB block above 768 KB).
The Z-100 is partially compatible with the IBM PC, using standard floppy drives. It runs a non-IBM version of MS-DOS, so generic MS-DOS programs run, but most commercial PC software use IBM BIOS extensions and do not run,[4] including Lotus 1-2-3.[5] Several companies offered software or hardware solutions to permit unmodified PC programs to work on the Z-100.

The Z-100 has unusually good graphics for its era,[4] superior to the contemporary CGA (640×200 monochrome bitmap or 320×200 4-color), IBM Monochrome Display Adapter (MDA) (80×25 monochrome text-only), and with 8 colors or grayscales available at a lower resolution than the Hercules Graphics Card (720×348 monochrome). Early versions of AutoCAD were released for the Z-100 because of these advanced graphics.[6]

Aftermarket vendors also released modifications to upgrade mainboard memory and permit installation of an Intel 8087 math coprocessor.

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What I need:
A good VGA 8bit color graphics card.
8bit sound card.
Display.

Docs:
https://www.old-computers.com/museum/computer.asp?st=1&c=261
https://en.wikipedia.org/wiki/Zenith_Z-100
http://www.1000bit.it/ad/bro/zenith/ZDS-Z150.pdf

Manual:
http://bitsavers.org/pdf/zenith/z150/Zenith_Z … anual_Guide.pdf
http://www.minuszerodegrees.net/manuals/Zenit … ce%20Manual.pdf