Tait T850 II Series, Service Manual

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M850-00
T855/856/857 SII - SI Conversion I2.1
Copyright TEL 31/09/98
2 T855/856/857 SII - SI Conversion
2.1 Introduction
You must make a number of modifications to enable a T850 Series II receiver, exciter or
transmitter to operate in a Series I rack frame. These changes can be split into two
groups, mechanical and electrical, as described below.
This procedure assumes you have already purchased the appropriate Series I conver-
sion kit:
• T855 - T800-70-0055
• T856 - T800-70-0056
• T857 - T800-70-0057.
If not, you should purchase one from your nearest Tait Dealer or Customer Service
Organisation before beginning the procedure.
It should take approximately 15-20 minutes per module to perform these steps.
Mechanical These changes involve:
• putting on a new front panel because of the differences in
height and width between a Series II and Series I panel;
• adding D-range locating pins as the Series I rack requires
them for alignment.
Electrical These changes involve:
• making sure there is pin compatibility for D-range 1 pin 7
between the Series II module and the Series I rack frame;
in Series I, pin 7 is allocated to audio 1 for the transmitter/
exciter, and audio 2 for the receiver;
• converting the exciter from rear RF output to front RF out-
put;
• disabling cyclic keying in the exciter.