Acom International 1000 Manual do utilizador - Página 15

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some components in the INPUT PCB and Rsw. This circuit tunes out the input capacitance of the tube. The swamping resistor Rsw is a termination

load for this circuit and can dissipate up to 100W of RF drive power.

Cathode resistor Rc creates DC and RF negative feedback, thus stabilizing the gain and equalizing the frequency response. The varistor VSsg in the

screen grid circuit protects the tube screen grid, and voltage regulator in the events of a flashover.

The combination Lp1-Rp1 in the plate circuit is a VHF/UHF parasitic suppressor. DC plate voltage is fed through chokes RFC1-RFC2 and the

capacitor Cb3 blocks it from the output. The output circuit comprises LP1, LP2, LL, CP1-CP3, and CL1-CL3 which form a classic Pi-L network and

suppress the harmonic frequency emissions. This tank is switched and tuned over the bands by S1A-S1C and the air variable capacitors CP1, 2 and

CL1, 2. The output signal is fed through an additional VHF low-pass filter for frequencies above 55MHz (Lf1, Lf2 and Cf). Then it is passed through the

vacuum antenna relay K1, wattmeter current transformer TA1, and a high-pass filter RFC4-Ca for frequencies below 100kHz, to the antenna output.

The chokes RFC3 and RFC4 keep track of the antenna relay contact conditions and together with Ca prevent the plate supply from reaching the

antenna. RFC4 shunts it to ground if the DC blocking capacitor Cb3 fails. The resistor Ra protects the amplifier from charging Electro-static energy fed

by the antenna.

The PLATE CAPACITIVE DIVIDER and RF WATTMETER are the main sources of information for the control circuit of the amplifier during the antenna

impedance matching process. The control circuit is based on the 80C552 micro-controller from Philips.

All voltages are delivered from the MAINS&LOW VOLTAGE and HIGH VOLTAGE SUPPLY PCBs. The control grid, screen grid and plate currents,

plate cooling airflow temperature, reflected power etc. are permanently monitored. Many software-derived protections are based on this information.

* Detailed electrical schematic diagrams are available from ACOM or from your dealer on request.

See S.5-3 for the method of reading the auto-protection signatures. You can decode them using the information below. *

The signatures are structured in two lines, three groups by six symbols for every one event of auto-protection. The last event is numbered as 1A-1B

pair of lines, and the oldest one is 7A-7B.

The meaning of the first group is as follows:

a) nA - the number of the trip;

b) Next three symbols mean the following:

PN0 - tests made during Power-On procedure, before HV is ON;

PN2 - tests made during Power-On procedure, after HV is ON and 1 second after step-start is closed;

SB0 - tests made in Stand-By, during the warm-up period or while entering Stand By (from Operate);

SB2 - tests made during Stand-By, after the warm-up period;

PR0 - tests made while entering Operate;

PR2 - tests made during Operate;

TR0 - antenna relay tests made while changing from Tx to Rx (during Operate)

TR2 - antenna relay tests made while changing from Rx to Tx (during Operate)

TR4 - antenna relay tests made during Tx (Operate mode)

TR6 - antenna relay tests made during Rx (Operate mode)

c) The last symbol of the first group designates the kind of the input parameter, which caused the protection to trip. The abbreviations in brackets

below are the signal names/designations according to the CONTROL PCB electrical schematic diagram and signal type:

1 - peak forward power (pfwd, analogue)

2 - reflected power (rfl, analogue)

3 - input (drive) power (inp, analogue)

4 - peak anode alternate voltage (paav, analogue)

5 - screen grid current (g2c, analogue)

6 - plate current (ipm, analogue)

7 - high voltage (hvm, analogue)

8 - exhaust air temperature (temp, analogue)

9 - drive power exists (*GRIDRF, logic)

A - antenna power exists (*PANT, logic)

B - output relay closed (ORC, logic)

C - arc fault (ARCF, logic)

D - control grid current too high (G1C, logic)

E - +24VDC power supply error (PSE, logic)

F - low airflow (LAIR, logic)

For instance, "1ATR4B" in first group would mean that the last auto-protection (1A) tripped by the antenna relay tests made during Tx - Operate mode

(TR4), and the "output relay closed - ORC" signal was failing (B).

The next five groups of symbols carry information about the analogue and logic values as measured by the micro-controller (at the moment of auto-

protection trip).

* Additional information is available from ACOM or from your dealer on how to interpret these values. Using an EXCEL APPLICATION (available from

ACOM or your dealer free of charge) and a PC, you can decode these signatures easily by yourself.

In case it is necessary to ship the amplifier please see S.7-3.

a) Frequency Coverage: All amateur bands 1.8-54MHz, extensions and/or changes on request.

b) Power Output: 1000W PEP or continuous carrier, no mode limit.

In continuous carrier modes (RTTY etc.) for transmissions longer than 15 minutes (up to several hours depending on

ambient temperature), the external auxiliary fan must be mounted.

c) Intermodulation Distortion: Better than 35dB below rated output.

d) Hum and noise: Better than 40dB below rated output.

Exhibit 8

6-5. Troubleshooting

7. SPECIFICATIONS

7-1. Parameters

15 -17