Maintenance; Cleaning; Fuse Replacement; Tube Replacement - Acom 1500 Manual

- "n" is the successive number of the event (nr.1 is the latest, nr.7 is the oldest one);
- A and B mark the first and second parts of an information screen pair.
Two lines, three groups by six symbols (36 symbols in total) are to be copied concerning every one of
the 7 memorized events, from 1A-1B through 7A-7B.
To decode the signatures please see S.6-5 (Troubleshooting).
After every signature listing the tube warm-up time is reset to 180 seconds
regardless of time in the OFF LINE state.

6. MAINTENANCE

If the characters on the VFD are dim, please follow the method of Display
brightness control described in S.5-1.

6-1. Cleaning

Do not use solvents for cleaning - they may be dangerous both for you
and for the amplifier paint or plastics.
Do not open the amplifier. Cleaning of the amplifier outer surface can be done with a piece of soft
cotton cloth lightly moistened with clean water.

6-2. Fuse Replacement

If it is necessary to replace the mains fuses, use only standard ones.
The two Primary Mains Fuses of the amplifier are located on the rear panel (Fig. 2-1). They are of the
fast (quick blow) type, 1-1/4 x 1/4 inch Cartridge Fuses, Size "0". Use 20A for 100-120VAC operation.
Use 16A for 200-240VAC operation (15A standard is also acceptable).
Besides the primary fuses, on the MAINS PCB (inside the amplifier) there are three small glass fuses
(5x20mm European size): one 100mA 250VAC normal blow; and two 2A 250VAC slow-blow.
These fuses should not be replaced by the user. Should one of these fuses be blown, it may be
indicative of a serious fault. A fault of this type will not occur under normal operating circumstances.
Replacing these fuses involves special skills and is inherently dangerous. For these reasons, we
recommend this work be carried out by a trained service technician.

6-3. Tube Replacement

A single 4CX1000A/8168 ceramic and metal tetrode is employed in the amplifier. Replacement is a
complex and potentially dangerous procedure. For this reason, we recommend this work be carried
out by a trained service technician. Check with your dealer before attempting to replace your tube.

6-4. The ACOM1500 Simplified Schematic Diagram

See Fig.6-1 ACOM1500 Simplified Schematic Diagram. The 4CX1000A/8168 ceramic and metal
radial beam tetrode (V1) is grid-driven. It can dissipate up to 1000W when forced air cooled and is
specifically designed for class AB1 RF linear amplifiers.
The input signal from the RF INPUT jack is passed through a broadband input matching circuit, which
consists of components in the INPUT PCB and Rsw. This circuit tunes out the tube input capacitance.
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