Rare Vintage Mission Electronics 776 Preamplifier Preamp Battery Powered 1980s

Description

It powers on, but I don't know how to fully test it. It most likely needs new batteries (maybe fuse). It has wear from use, looks good overall.
Please see all photos for condition and feel free to ask any questions.
***Sales tax of 7.75% is added to all California transactions. Please be aware that some other states have recently required that sales tax is collected. This is automatically added to your transaction by eBay and they send it directly to your state government. We, the seller, have no control over this portion of the invoice. Thank you for understanding.***