altec 1591a

I don't know if this is the right place but I a currently working on an altec 1591a preamp/compressor.

Problem was that the meter stayed at around 10db of compression al the time.

I checked the power supply wich has been recapped by someone and is ok.
Then checked al the connections and they are ok.

Didn't find any resistor out of spec so al should be good....
I discovered something is weird with the sidechain amplifier.
The replacement PNP transistors should be 2N3906. It changed a little but still compressions is stuck at 10db.
Then I started measuring and it looks like the sidechain amplifier is sensitive to the hfe of the transistors used..... should it be like that? I would never do that...
Schematic can be found here

When I made R7 a little bit smaller I was able to set the meter to 0 and can have around 20db of compressions. After that the input amplifier starts to clip.
According to the manual it should be possible to get 35db of compression
I only can get this when the treshold is set to 0db. at +8db treshold the input amplifier starts to clip earlier.
it looks as if the input amp doesn't have enough gain?
I'm really puzzled with this thing.....
If anyone has experience with these compressors please tell me :)