FMJ Dv29 Circuit description.
Overview
The DV29 is effectively a no compromise version both electronically and mechanically of the DV79.
The player is based around acclaimed Zoran Vaddis V chipset coupled to high specification Wolfson D to A converters for all six audio output channels, also featured in this design is a HDMI transmitter with digital Video and a Audio output capable of Digital Surround.
The DV29 and the DV79 use the same main board and power supply stage but with many of the components either upgrade or replaced with different topologies, many of the critical audio/video components with 0.1% tolerance within the DV29 and we also have an extra toroid power supply for the Audio stages.
Both the HDMI chip and Video encoder are of a higher quality than those found inside the DV79.
Power supply board.
Mains power arrives at IEC inlet socket SKT1 and is filtered by EMC choke LI and Y caps C3 and C4, mains switch SW2a/b switches both Negative and Live phases before the power reaches the mains select switch at location SW1 the switch allows the primary windings of the transformer TX1 to be wired in either Parallel or Series configuration.
The Bridge rectifying Diode package at location D1 forms the basis of the conventional power stage and supplies a VN35V6
We will also see a simple A.C present circuit this is used for delayed output relay operation and fast relay closure under interrupted supply conditions thus preventing
Switch mode
The switch mode supply is formed around the Driver/Control chip IC1 UC3843 (used in regulating mode). The chip is referenced the
Fig 1 PSU clock control and IC305 line status
Fs | PSUFS1 | PSUFS0 | PSUCLK |
Frequency | Pin 11 | Pin 12 | Output Pin 5 |
select | IC305a | IC305a | of IC305a |
44.1 kHz | 0 | 0 | 44.1 kHz |
48 kHz | 0 | 0 | 48 kHz |
88.2 kHz | 0 | 1 | 44.1kHz |
96 kHz | 0 | 1 | 48 kHz |
176.4 kHz | 1 | 0 | 44.1 kHz |
192 kHz | 1 | 0 | 48 kHz |
Others | 1 | 1 | OFF |
The PSU sync signal is driven into the power supply via Resistor R9 if no Sync is present the unit is set to free run at xxxx due to the RT/RC network attached to Pin 4.
IC1 is running in regulated mode and monitors the voltage output on the +5V and +3V3 D.C lines, the two voltages are summed by TR8 and Driven into the VFB and Comp inputs of IC1, the Voltage is then regulated by changing the time base of the PWM output at pin 6 (longer the time base the lower the voltage), the PWM switching frequency is driven into the
The D.C outputs from the switch mode have extensive switch mode noise removing filters these are seen as 100n caps down to ground and Wire wound inductors in series with the supply rail.
Power supply main board
All the power supply rails are supplied to the main board via the 32 way FFC conector at location CON1001.
The Digital supplies from the switch mode stage of the power supply arrive as 3V3D, +5VD and +12VD we also see the Display board power supplies arrive as
The 3V3D rail is the main 3V3 rail used to power the digital circuitry; +5VD is used for all 5v Digital/Video supplies the +12VD is used for Scart switching and to power the HDMI circuit (not DV78).
The 1V8 rail is derived from the 3V3 rail and is regulated by the adjustable regulator at location REG1003.
