Hi,
My Console has the 82E01 K1097 Channel Amp Card with Transformer and a little Daughter Board in-place of the position of IC T3.
I traced all the connections and made a schematic. Please feel free to point out any Error you may find.
I tripple checked the designators and values, but there is no guarantee that it is 100% accurate!
(I left out the bypass caps of the ICs, also the power wiring and the P48v Resistor).
There are three extra wires to make the needed connections, this is marked in the Schematic.
Some traces have to be cut on the top and bottom side of the PCB as well.
The Daughter Board is Highlighted in a blue rectangle.
Some Notes on the original Schematic:
R60 is found two times in the Schematic. 100k in the Feedback of "T3" and 10K between C35 and Inv In of T4.
33p across R60 100K is not in the original Schematic.
C8 100uf at the Output of T4 is removed with this mod.
R58 and RC14B is omitted, as stated in the Schematic Rev 9 and up, even my boards are only Rev 7.
I found some Quotes from Amiliar and NJM wich I found interesting, maybe you can chime in and contribute to this topic?!
Some were pointing out it has something to do with a "line to Meters" Mod, but as far as I understand the Schematic,
it replaces the T3 with a extended Circuit, wich is involved in the Line trim circuit.
Looks like the second Gain Stage of the Line Amp was moved after the Channel Input select,
wich explains why the Line trim affects the Mic Input Level.
It also looks like the TR1 changes the Feedback Gain when either Line In or Mic in is selected.
Mic Input trim (via Line level Pot) is only a few db (on my Console).
I am wondering if this is a Mod for Broadcast Consoles.
My Console was originally order by the Danish Radio Broadcast Company.
It came with Rotary Switches instead of the Mic Gain Pot.
The p48v is globally activated in the Center Section.
That would explain why I can trim my Micpreamp by a few db with the Line Trim Pot.
(See topic
https://forum.sslmixed.com/index.php?topic=1964.0)
Hope this helps...
Best Regards,
Tilmann
