IF THE DISPLAY
DOES NOT COME ON?
Check d.c. power supplies on power pcb
They should read as follows:-
Plug 7 Pin 3 - 12V
Plug 7 Pin 1 or 6 - 5V
Both these voltages are referred to 0V on pin 2 or 7 of Plug 7.
If they are not correct check power supply components particularly
transformer T1. If display is still off check lead connection to
display pcb or change power supply board.
Over-temperature neon
constantly on.
(
A float switch to ensure there
is sufficient liquid in the tank to
cover the heater, is fitted to
both GD100 and GD120. An
over temperature cut-out,
which can be adjusted from
the front panel and is designed
to protect users samples, is
fitted to the GD120 only.)
Check that float (stainless steel bulb situated adjacent to heater) rises
up with water level. If it does not check that shaft slides up and down
freely and operates the micro switch. Check that the float has not
sprung a leak and filled with water. Disconnect unit from mains supply
and remove leads from float micro-switch. With multi-meter set to
resistance range check that micro-switch switches on and off as lever is
operated.
Check the over-temperature cut-out by disconnecting the unit from
mains supply and removing leads from cut-out terminals. With multi-
meter set to resistance range check the resistance between the
terminals is a short circuit when cut-out is turned fully clockwise and the
reset button is pressed. Turn cut-out fully anti-clockwise and check that
resistance between terminals is open circuit.
IF TEMPERATURE
DISPLAY SHOWS
open
Probe is open circuit, or unplugged from PCB.
Replace probe or reconnect plug.
IF TEMPERATURE
DISPLAY SHOWS
shrt
Probe is short circuit. Check probe resistance.
See table on page 18. Replace if necessary.
GD100/GD120
Part No. 17592/Issue 1
July 2002
Page 10
Summary of Contents for OPTIMA RANGE GD100
Page 25: ...B x4 A C Fig 7 Fig 8 Fig 9 GD100 GD120 Part No 17592 Issue 1 July 2002 Page 25 ...
Page 26: ...D E x2 F PCB Clip D Fig 10 Fig 11 Fig 12 GD100 GD120 Part No 17592 Issue 1 July 2002 Page 26 ...
Page 28: ...Part No 17592 Issue 1 July 2002 Fig 16 J K x4 L Fig 17 M M M Fig 18 Page 28 ...
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