Tait T850 II Series, Service Manual

Page: 67 / 370

M850-00
T855 Functional Testing B4.1
Copyright TEL 31/09/98
4 T855 Functional Testing
Caution:
This equipment contains CMOS devices which are susceptible to dam-
age from static charges. Refer to Section 1.2 in Part A for more infor-
mation on anti-static procedures when handling these devices.
The following test procedures will confirm that the T855 has been tuned and adjusted
correctly and is fully operational.
Note 1: In this and following sections deviation settings are given first for wide
bandwidth sets, followed by settings in brackets for mid bandwidth sets ( )
and narrow bandwidth sets [ ].
Note 2: Unless otherwise specified, the term "PGM800Win" used in this and follow-
ing sections refers to version 2.00 and later of the software.
Refer to Figure 4.3 for the location of the main tuning and adjustment controls, and to
Section 3.3 for the test equipment set-up. Refer also to Section 6 where the parts lists,
grid reference index and diagrams will provide detailed information on identifying and
locating components and test points on the main PCB. The parts list and diagrams for
the VCO PCB are in Part E.
The following topics are covered in this section.
Section Title Page
4.1 Current Consumption 4.3
4.2 Sensitivity 4.3
4.3 Switching Range 4.3
4.4 Audio Distortion 4.4
4.5 Ultimate Signal-To-Noise Ratio 4.4
4.6 De-emphasised Audio Frequency Response 4.5
4.7 Noise Mute (If Linked In) 4.6
4.8 RSSI (If Fitted) 4.6
4.9 Carrier Level Mute (RSSI Fitted & Carrier Mute Linked In) 4.7
Figure Title Page
4.1
4.2
4.3
T855 De-emphasised Audio Frequency Response
T855 RSSI Voltage vs Signal Strength
T855 Main Tuning & Adjustment Controls
4.5
4.6
4.9