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Service Manual DT81
Issue 1.0




DiVA DT81
Digital Radio Tuner




ARCAM
Contents List




! Contents list


! Circuit description


! Service guide


! Circuit diagrams


! Component overlays


! Circuit board parts list


! General assembly parts list
Z201 is the SPDIF transmitter. Each one of the differential ouputs is
DT81 Circuit Description used separately. SPDIF_OP is for the optical output, SPDIF_CX is
for the coax output.
Summary

The L918 forms the basis of the DT81 DAB tuner. All the circuitry
DAC
of the tuner is on the same board, with the exception of the front
panel PCB. Z101 is a CS4327 D-A converter, followed by filter/buffer Z102.
The tuner is based on the Roke Manor gold card which provides the This is followed by ac coupling capacitors. The relay RLY1 is the
RF receiver and DAB decoding. To accompany this module the DAB last stage before the phono output connectors. 2 stereo outputs are
motherboard has various power supplies, a Hitachi H8 provided on SK101. SK102 is an input which gets routed through the
microcontroller, a D-A converter with output buffer, and an SPDIF relay when the relay is off.
transmitter. An external FM tuner can be connected to this, in order to avoid
taking up an extra input on the amplifier. When the tuner is off or in
bypass mode, the FM tuner is routed to the output.
Power supplies and muting
The digital audio outputs are also shown on this sheet. TX101 and
associated components provide an isolated unbalanced SPDIF output
The mains transformer T1 is used for 230V and 115V operation, the on SK103, and Z4 produces an optical output.
voltage selection is done by fitting different fuses. F1 160mA is
fitted for 230V and F2 250mA for 115V.
The front panel board is powered from the 7.5V unregulated supply
(it has its own regulator). The digital supplies are switched by SW3,
Software notes
while the analogue supplies are on all the time while the mains is
connected. The system has non volatile storage in the form of the EEPROM,
Z202. The following information is stored there and is remembered
at power up:-
Service data - all the IDs and static prog types of the services
Regulated supplies available in the ensembles found in the last search. This is the
information viewed when turning the knob.
P15V, N15V. +/-15V for the output buffer and DAC 5V regulator. Service selected - last service selected.
P5VDAC. +5V supply for DAC. Display mode - prog type, dynamic label, data rate or signal quality.
P5VDAB. 5V supply for DAB module. Display brightness - off, dim or bright.
P5V. +5V supply for digital circuits - Micro and SPDIF transmitter. Compression level - off or 1-5.
P10V. +10V supply for DAB module. The following parameters are NOT remembered:-
P7V5_UR. Unregulated 7.5V supply goes to front panel. Engineering mode. If the unit is turned off while in engineering
mode (or test mode), it will default back to user mode on power up.
Z9 is a Toshiba TA7317. This controls the muting/bypass relay. The Bypass mode - the unit will always power up not in bypass mode.
same relay is used for power on/off muting and also FM tuner bypass Secondary services - if a secondary service is selected when it is
mode. switched off, it will power up with the parent service selected.
The muting circuit has a time constant of 2.5 seconds, so there is Erasing the EEPROM - to erase the EEPROM, go into engineering
always a 2.5 second delay when un-muting the output. mode (SELECT +8), then hold down preset buttons 1,4,5,8. The
The FM tuner bypass switch is shown on this sheet (SW2) and is display will say `ERASING EEPROM' followed by `PASSED
accessed from the front of the unit. EEPROM TEST' then `EEPROM ERASED'. If you switch the
power off and on again, it will come on with all the parameters reset.

Micro, DAB module, SPDIF Display mode - prog type
Display brightness - bright
Compression - off.
Z204 is a Hitachi H8/3048F 16 bit microcontroller. It has FLASH Selection Mode