Table of Contents
Advertisement
13. T
ROUBLESHOOTING
The Novatech 1732 Oxygen Transmitter has proved an extremely reliable instrument. The troubleshooting
guide here is based on an analysis of the potential problem that may occur after many years of operation in
the field. A current list of problems and solutions can be found on the Novatech web site at
www.novatech.com.au
when any are identified.
13.1 First Approach
The probe will not heat up.
Turn the power off, remove and check 2 x 20mm glass fuses. If either of them is blown, check the probe
heater resistance between the two white wires that come from the probe. It should be 110 +/- 15 ohms, and
both wires should be open circuit to earth. If not, replace the probe.
Is the 'B' shown on the bottom left hand corner of the display? If not, check that the burner is enabled with
either a link between terminals 10&11, BURNER INPUT, or is enabled with a connection to a voltage-free
contact from the main fuel valve to these terminals.
The display is blank and there is no backlight on.
Measure the power supply voltages at the test points labelled COMM and +5v at the right-hand side of the
main PCB 1730-1. It should be 5 +/- 0.15v.
Turn off the power and remove the main shield. Check that the plug-in fuse FS1 has not blown. It should
only be replaced with a 1A, 250v fuse if it has blown.
Is the mains power being supplied to terminals 36&37 and is it between 100 and 240VAC? If may be
necessary to replace the switch mode power supply, PS5, APC-5S.
An 'ADC Calibration Fail' alarm has occurred.
Turn the transmitter off and remove the main shield. Turn the transmitter back on and measure the voltages
on the 'Acom' test points. With the negative lead on the centre terminal the other 2 terminals should
measure 12 +/-0.3v. If not, replace the small DC-DC converter PS4.
An 'Output 1 (2) Failure' alarm has occurred.
Turn the transmitter off and remove the main shield. Turn the transmitter back on and measure the voltages
on the 'D1com' test points. With the negative lead on the centre terminal the other 2 terminals should
measure 12 +/-0.3v. If not, replace the small DC-DC converter PS4.
A 'Heater 1 (2) Failure' alarm has occurred.
The software has found that the SSR4 has failed. If a single oxygen probe is being used and you need to
get the transmitter back working quickly, use the CALIBRATION menu function 18, Heater SSR Select, to
change the heater output terminals. See chapter 8.2.9, Heater SSR fault correction.
A 'BBRAM Fail' alarm has occurred
Replace the BBRAM, MEM1 on the 1730-1 main PCB.
13.2 Detailed Fault Analysis
The 1732 transmitter has a diagnostics mode built into the software. This mode allows detailed analysis of
the hardware of the transmitter, but does require a level of competence in electronics.
The diagnostics mode is selectable by turning the 'Diagnostics' DIP switch to ON and then turn on the power.
There is a separate Diagnostics Mode Manual available that describes its use. Ask Novatech for more
details.
August 2018
Technical Manual
1732 Oxygen Transmitter
61
Advertisement
Table of Contents
