A new piece of equipment to lab. GW GFG-8020G Function generator

Hi, because schools electric lab moves to different place, they cant take all stuff with them. So teacher gave me this function generator because my lab lacked proper function generator. it works like charm, no need for repairs or anything .

it has sine/triangle/square wave, adjustable from 0.2hz to 2Mhz, 1/10/100/1k/10k/100k/1M push buttons set range. voltage depending from load from 10-20v. output impedance is 50Ω
connector are BNC with shell connected to safety ground. Connectors consists of: input VCF, output TTL/CMOS(both only square wave) and normal 50Ω output.
Dc offset +10 to -10, +5 to -5v @50Ω load. attenuation -20db is selected form amplitude switch.
And their adjustment knobs, with pullout switching between features.
Case is held in place by 4 screws from bottom. Back panel has only connector to mains cord. See photos for interior, what i like about interior is that there are no SMD, just personal opinion. I did find user's manual, but if someone has/finds SERVICE manual, i would appreciate it.
comments welcome!