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The main Power Supply Unit (PSU) consists of two main assemblies:
-
a rectifier and switching mode stage, not insulated from the mains; they provide a preliminary regulation
at 390V and power factor correction (PFC); the latter serves to minimize the mains-frequency harmonics
currents, thus ensuring a high power factor of the consumed current, and also limiting the start-up mains
current during shifting of the amplifier to the operating mode;
- mains-separated switching mode converter “390/50V” which supplies the power amplifier module with
+50V, insulated from the mains and regulated DC voltage; this is the main power supply of the amplifier
and it is protected against excessive consumption over 1200W; it is controllable ON and OFF with a logic
signal from the Control unit in the amplifier Operate and Stand-by modes respectively.
In addition to the low-power and the main (+50V/1200W) power supplies, the PSU produces also three auxiliary
voltages:
- +13V DC voltage (non-insulated from the mains) for PS unit's own needs: primary turning on and
supporting the “PFC control" assembly in the Power Supply unit;
-
+5V regulated DC voltage, insulated from the mains: for power supply of the Control unit, the low-power
circuits in the Power amplifier module, Filters, and Wattmeter units of the amplifier;
- +26V regulated DC voltage, insulated from the mains: this is the operating voltage for the relays coils,
fans, and other low-power circuits in the amplifier.
Very efficient symmetrical L-C filters are placed at the input and output of the power supply unit. They suppress
the interferences in the radio frequency spectrum, providing perfect electromagnetic compatibility (EMC) with both
receivers and transmitters in the shack, exceeding the worldwide adopted standards. They also give the power
supply an extra resistance against external interferences propagating along the power network.
7-4.
Using the fault codes (signatures) for diagnostics
In the nonvolatile memory of the Control unit there is room for data of the last 28 protection trips of the type
“serious fault” (HARD FAULT) – see S. 4-6(c). These are the values of all logic and analogous signals,
concerned to the regime and control of the amplifier, as well as the time when a problem has occurred (in worked
hours), and others. The information can be presented on the amplifier screen or it can be downloaded and
archived in a plain-text format file. See also the menu FAULTS LOG - S. 5-5.
The data can be downloaded from nonvolatile memory of the amplifier through the built-in RS232 interface and
stored in a computer file even when the amplifier cannot or should not be turned on after a serious fault – it is only
needed to apply external power to the Control unit in either way as described below:
- through the connector for the CAT/AUX interface on the amplifier rear panel; without dismantling the
amplifier, on the “Debug mode” input (Table 2-1) a DC voltage b8 and +15V towards ground is
applied. The consumed current is up to 0.4A in this mode;
-
if the Control board has already been removed from the amplifier for another reason, it can be powered
directly with +5V and the faults log also downloaded via the RS232 interface, connecting the board
according to its own schematic diagram, shown in the Technical CD (option to the amplifier); the
consumption from +5V is the same: up to 0.4A.
In the FAULTS LOG reading mode (Fig. 5-5), the Control board automatically begins to transmit the data from its
nonvolatile memory through the RS232 interface. Depending on the number of fault events stored in the memory,
the transmission may take between 0.5 and 12 seconds. A pause of 6 seconds follows the end of data
transmission which resumes again. The data can be archived in a plain-text format through a computer using a
standard program emulating a terminal (TTY).
You can send the recorded file to your dealer or to ACOM accordingly. They could also provide the necessary
instructions, if you choose to decode the downloaded hexadecimal data by yourself.