clock ASTON MARTIN DB7 1997 User Guide

Air Conditioning
Manifold Gauge Set 5=2?
Manifold Gauge Set
The manifold gauge set is a most important tool for
fault diagnosis and system efficiency assessment.
The relationship to each other of HIGH and LOW
pressures and their correlation to AMBIENT and
EVAPORATOR temperatures must be compared to
determine system status. Because oi the heavy
reliance upon this piece of equipment for service
diagnosis, ensure that the gauges are calibrated
regularly and the equipment is treated with care.
BLUE LOW SIDE RED HIGH SIDE
LOW

m
m

Manifold.

The manifold is designed to control refrigerant
flow. When connected into the system, pressure is
registered on both gauges at all times. During
system tests both the high and low side hand valves
should be closed (rotate clockwise to seat the
valves). The hand valves isolate the low and the
high sides from the centre (service) hose.
Low Side Pressure Gauge.
This compound gauge
is
designed to register positive
and negative pressure and may be calibrated as
follows:
• Full Scale Deflection - 0 to 24 bar pressure
in a clockwise direction
• Otol bar FSD negative pressure in a counter
clockwise direction.
High Side Pressure Gauge.
This pressure gauge may be calibrated from 0 to 34
bar FSD inaclockwisedirection. Depending on the
manufacturer, this gauge may also be of the
compound type.
Figure 1
The gauge set (Fig. 1) consists of a manifold fitted
with:

1 Low side service hose - BLUE.
2 Low Side hand valve - BLUE.
3 Low pressure compound gauge - BLUE.
4 High pressure gauge- RED.
5 High Side hand valve - RED.
6 High side service hose - RED.
7 System service hose - NEUTRAL COLOUR
(commonly yellow).
8-38 May 1996

^?
The Aston Martin Lagonda Diagnostic System
Installation Instructions

1.
Switch off the PDU and remove all cables.

2.
Remove the cover screw (Fig 23) and remove the cover.
3. If damaged, remove the old foam gasket from the cover and replace with the new one supplied.

4.
Note the orientation of the connector. Disconnect the connector and remove the old battery pack.
5. Fit and connect the new battery pack (Fig 24) with the black cable towards the touch screen.
6. Refit the cover and cover screw.
7. Refer to the Battery Charging instructions for recharging times.
Changing the Dust Filter
The electronic module has a dust filter fitted to the underside of the module. Every three months a new filter wil
be supplied. To change the filter, proceed as follows:

1.
Switch off the mains supply and pull out the old filter (Fig 25).

2.
Feed in the new filter with the blue side facing in, pushing it well into the corners of the holder.
3. Switch on the mains supply.
Figure 25. Dust filter replacement Figure 26. Support arm adjustment
Support Arm Adjustment
Periodically the support arm mechanism may require adjustment.

1.
Remove the cross head arm fixing screw.

2.
Using a suitable screwdriver, turn the tensioning screw (Fig 26) anti-clockwise half a
turn.

3. Refit the leg fixing screw and repeat the operation on the opposite side.

4.
Check that the arm tension is enough to support the weight of the PDU without movement.
VIA Carrying Case
The VIA unit (0018) is secured into its carrying case with two fixing screws from the underside of the case. If a new
VIA is required, remove the two fixing screws and lift the VIA from the carrying case. Return only the VIA for
replacement, do not return the carrying case.
May 1996 9-23

The Aston Martin Lagonda Diagnostic System
Users Guide ^?
Datalogger Timing
Select the 'clock' icon from the main menu screen.
Confirm the selection using the 'tick'
icon.

The Datalogger timing screen should now be displayed.
Datalogger Timing
Signals
Sample Interval
Record time
Pre-trigger
Post-trigger
00:33:20

50%
00:16:40

50%
00:16:40
'^
23]
Datalogger Timing
The Datalogger timing screen allows customisation of the
sample interval and duration of data capture.
The display will identify the number of parameters
(channels) which have been selected to be recorded by
Datalogger.
Timing changes can only be made while data capture is
inactive. Entering Dataloggertiming while vehicle data is
being captured will display the current
settings,
but disable

selection.

Signals
The signals are the number of parameters set for sampIing
by Datalogger.
Sample Interval
The sample interval (frequency) defines the time interval
between successive block requests for all recorded
parameters.
The sample interval is selectable to enable fast response to
intermittent faults.
Note: Very short sample intervals may reduce test
duration
because ttie
PDU memory
becomes
full of
data.

Select the sample interval rectangle.
Acaiculator-style icon should nowbedisplayed. rrr?]
^
Aswellasa calculator-style icon beingdisplayed
there will bea hare
icon,
selecting this icon will
automatically set the fastest sample rate for the
selected parameters.
Note: The fastest sannple rate set using the 'hare' icon may
be too fast for some applications.
Select the calculator-style
icon.

A new screen should now be displayed.
Enter Test Duration
IDD 33 EDI
CL m m [Z]
Ci] ra [I]

1
1 2 1 3 1

0
1
Test Duration
Enter the required value in milliseconds up toa maximum
of 60,000 mS (1 min). At this stage Datalogger will not
verify if the entered sample interval can be achieved.
When Datalogger is actioned to start recording vehicle

data,
and the sample interval is shorter than the fastest
achievable capture time, a warning screen will be

displayed,
requesting changes to the sample interval.
Record Time
The record time (test duration) defines the length of the
data slice which will be preserved for analysis after the
fault occurs. The selected time will be split equally before
and after the fault trigger, e.g. a 10 minutes recording will
preserve data from 5 minutes before to 5 minutes after the
fault.
At the end of the record time the PDU will automatically
stop recording.
The record time is entered in the same way as the sample

interval,
by enabling the rectangle and selecting the
calculator-style
icon.

9-60 September 1996