DOWNLOAD Sharp AR-5132 (serv.man118) Service Manual ↓ Size: 9.48 KB | Pages: 1 in PDF or view online for FREE

The “H4” code is displayed if the temperature of the fuser unit decreases to meet its lower
threshold limit of 148 Degrees Centigrade.

If the start key is pressed whilst the heater lamp is off, the temperature of the fuser unit will
continue to reduce until a set temperature is reached.  At this point the new type of Fuser
Heater Lamp Control that is used on the AR-5132 called “Flicker Control”, will gradually
increase the voltage to the fuser lamp to increase the fuser temperature.

Under certain circumstances, the gradual voltage increase of the heater lamp does not
compensate quick enough for the continued reduction of fuser temperature as paper passes
through the unit, if this occurs an “H4” code can be displayed.

[Flicker Control]
Flicker Control is incorporated in to all European production machines in order to allow a
gradual increase in Heater Lamp Voltage and eliminate any current surge.
Flicker Control can be visually seen as the fuser unit heater lamp is controlled.  The voltage to
the heater lamp is gradually increased until it reaches full power.

Solution:-
If this symptom is experienced, in the short term as a solution, we would recommend that the
Fuser Target Temperature of the machine via Simulation 43-01 is increased to 205 Degrees
Centigrade and that the Fusing Curl Mode Simulation 26-15 is enabled, by changing the
default setting of “0” to “1”.

By increasing the target temperature of the fuser unit we are effectively increasing the upper
limit and so allowing the machine an increased time scale before the lower limit would be
reached.  At present we have had no report of the “H4” problem occurring whilst the fuser
target temperature is set to 205 Degrees Centigrade.

By enabling the Fuser Anti-Curl Mechanism we are instructing the machine to rotate the fuser
unit for a longer period of time during warm up.  The effect of this is that the lower fuser
roller absorbs an amount of heat from the upper roller and so helps to overcome paper curl,
but also helping to keep the fuser unit at an overall more constant temperature.

Please advise our Technical Administration Department of any changes to your Service Department
details (i.e. fax number, telephone number, address, etc.) on fax number 0161 205 0014.