This website offers historic aerial photographs of Chicago going back to 1938. Of course, you are limited to the details of buildings that are visible from above.
http://www.historicaerials.com/
The best place to find historic photos would be from company documents, such as newsletters, annual reports, etc. Unfortunately, these items are hard to find today, as no one really saw the value in saving them.
Doug Harland (drh4683) has collected some "ephemera" from Chicago electronics manufacturers from the estate sales of former employees, he may have some Admiral paperwork that would be helpful.