SAM-A1 Owner’s Manual
FSL0132
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FSL0132 Version 5.1 © 2020 Fireworks Solutions Limited Page 8
3.2.
Hazardous Voltages & Fragile Components
As specified in section 2.1, the equipment contains hazardous, potentially lethal voltages and must
be fully isolated from the mains supply before removing any covers or unplugging any of the
valves. (See also section2.2; surface temperature warnings).
POTENTIALLY LETHAL VOLTAGES INSIDE
.
WARNING DC voltages as high as 400VDC may be present inside the unit
when in operation.
In addition to the hazard presented by the mains supply voltage, valves require hazardous DC
voltages for their operation. These DC supplies are smoothed using reservoir capacitors that are
capable of delivering significant short term current. The combination of high DC voltages and
available at high currents can be LETHAL.
In normal operation, when used as intended, these hazardous voltages are not accessible to the
user and the user is protected from them by a combination of insulation and earthed protection
offered by the metal case.
The IP20 rating specifies protection against solid objects >12mm i.e. fingers from gaining access
to hazardous voltages, the largest apertures are 5mm diameter vent holes around the valves and 4
x 20 mm ventilation slots in the lid and base. A standard test finger in accordance with IEC60529
cannot access any hazardous voltages through any of the apertures in the case. DO NOT insert
any conductive object/tool in to any of the vents/holes in the case.
The equipment is not protected against moisture ingress. In the event of a spillage on to the
equipment immediately isolate the equipment from the ac mains supply, then remove all
connections to the amplifier and seek advice from FSL.
Do not operate the amplifier in an environment where there is high humidity, water or splashing
with water is likely e.g. bathrooms or within 2m of a sink or tap.
All adjustments are to be made with the correct trimmer resistor adjustment tool. The correct tool
has a metal blade that fits in the trim put screw slot but a plastic handle the fully isolates the
operator from the circuit. The correct tool is one of the following:
Vishay ACCTRITOB308 (RS stock number: 543-434)
Bourns H-90 (RS Stock number: 743-2479)
Thermionic valves and safety
WARNING the outer case of the Valves is made from Glass and they are FRAGILE.
If the valves are broken; the hazardous voltages will be accessible to the user/operator.
The unit must not be operated with missing or broken valves.
Inspect the equipment before connecting to a mains supply; if any of the valves appear damaged
or is missing, disconnect the supply immediately.
NEVER remove valves while the equipment is connected to the mains ac supply.
