Zenith Beta VCRs were all clones of Sony models. That one looks like a clone of the Sony SL-2500, which was the first low-profile, stereo-component-style VCR that I remember. Here are some pictures:
http://www.betamaxcollectors.com/son...elsl-2500.html
The power supply on this should not be too complex, so basic troubleshooting techniques should get you started, even without that Sams manual. (Trace from the power cord and switch to see if it uses a power transformer first, and if it does not, plug it into an isolation transformer to do your repairs. Check voltages from the transformer output, then from the whole power supply which may have its terminals marked where they connect to other boards, and so on. Do visual checks on electrolytic capacitors, but ideally use an ESR meter on each one in the PS, as a start.)