User manual and Service manual

I just bought a Used Sechrist 3600e hyperbaric chamber. I need to perform a complete inspection/maintenance on it now. It didnt come with any of the manuals. Likely most any Sechrist manual will work. Specifically today I need to find if it has a battery. I plugged it in yesterday and got a power indicator light, but no other electronics worked. Likely today I will find the battery is charged, but its 11 years old and therefore should be replaced. Location? A manual will save me a lot of time and assure I dont miss anything. Next question, there is a multi pin cable that connects on the left side near the door locking mechanism. What is the purpose of this cable and where does the other end connect?