Circuit Description - TC Electronic Finalizer Epress Technical & Service Manual

Circuit Description

The Finalizer Express consist of a front, a digital, an analog and a power supply section. Here is a brief description of the sections:
Front section consist of two boards placed in the front profile. The main front board
has two matrix circuits; one for LED's and one for keys. The 7 pots are scanned by
IC8. The EEPROM contains the serial no.
The LED front board is fitted with the LED's and key switches.
Digital section is placed mainly in the middle and in the left side of the main board.
The digital section contains the Reset, MPU, SRAM, DSP, DARC, Sound RAM, FLASH,
Interfaces and PLL circuit.
Reset controls the MPU and the DA.
The Software for MPU is loaded into the FLASH. The MPU controls DSP, SRAM, Jeida,
Front, MIDI, External Control In and analog gain settings.
The major task for the DSP is to "calculate" sound. It also generates the 80MHz clock for
the DARC chip.
The DARC chip controls the sound data to/from; DSP, Sound RAM, digital in/outputs and
AD/DA converters.
Interface for MIDI and External Control In consist almost of discrete components.
The interface for the front has an integrator, which converts a 3.3kHz square wave to a
negative DC voltage for the display contrast. By changing the duty cycle of the square
wave the DC voltage and thereby contrast will also change. An attenuator allows the MPU
to measure the contrast voltage.
The PLL circuit (placed on a separate board) makes a very stable frequency at 256 x sample
rate, this frequency is divided down to 64 x sample rate and to 1 x sample rate by the DARC.
The PLL has its own power regulation.
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TC Electronic A/S
Analog section is placed mainly on the right side of the main board.
The analog input is balanced, thus pin 3 should be connected to pin 1 when used with
unbalanced equipment.
Analog Input levels and Analog Output levels are controlled by digital potentiometers. These
potentiometers are located in a single chip, IC33.
The A/D converter is a 24bit converter . The A/D and D/A converters have also a separate
power regulation.
The D/A converter is also 24bit. A DC voltage is applied to the left & right signal output at
the converter.
After the D/A comes a 2nd order filter, then the output level and then a 1st order filter.
An electronic balanced circuit perform the output stage. Again, XLR pin 3 should be
connected to pin 1 when used with unbalanced equipment.
Power supply section consist of a separate Power Supply Module and some regulation
circuits on the main board.
One of the regulation circuits has an electronic switch for the +/-15V. But the electronic
switch for the +5V is mounted inside the Power Supply Module. The switches are controlled
by the Stand By circuit. The Stand By circuit is supplied from a separate power wire from the
Power Supply Module.
This service manual does not contain schematics for the Power Supply Module, because any
attempt to repair the module must be completed with some safety tests such as high voltage
and EMC test. Hence it is strongly recommended that the entire Power Supply Module is
replaced in case of malfunction.
Finalizer Express Service manual page 13