Arcam AVR600 avr sm

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ARCAM

AVR600 Service manual issue1.2

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L123AY- Connection board and PSU

This PCB provides the power for the unit through CON203:

+5V_STBY - 5V standby supply L118 R8232, L126 display (on in standby)
+3V3 PW338 - L122 PW338 supply (on in standby)

1V8D - L122 PW338 supply (on in standby)

+5V_1 - general 5V supply

+6V_1 - L156 DSP, L126 Display & L119 NET supply

+4OV_VFD - L126 Display

+15V - linear +15V supply

~15V - linear -15V supply

LK100 or the thermal switch from the power amp transformer is required to
pass the live mains. SW101 switches between 230V & 115V.

R101 & R102 are NTC parts to prevent inrush currents when the power amp
is turned on.

CON202 takes the Clk PSU sync signal from L121, Relay SW from L122 (to
turn on the main supplies) and /AC present back to L122. /AC present is
generated from the standby transformer secondaries with D200.D210 &
TR200. This will prevent the unit from starting if it is not low.

The standby transformer is rectified with DBRZOO (GBU4K) to give
UNREG_PW338 which is used for the 1V8D (REG206 - LM2670),
3V3_PW338 (REG201 - LM2670). The 12V for the relays to switch the
secondaries are also generated from REG207 (LM7812) which is then
regulated down to give +5V_STBY REG200 (LM7805).

When the signal Relay SW is taken high by the PW338, the secondaries of
the system & power amp transformer are switched in (RLY101 & RLY102).
This enables +15V, -15V (REG204 & REG205) & +5V_1 & +6V_1 (REG202 &
REG203).