Tait T850 II Series User Manual

C5.4 T856/857 Fault Finding M850-00
31/09/98 Copyright TEL
5.4 DC Checks
5.4.1 Power Rails
Refer to the test points and options diagrams in Section 6 for test point locations, and to
the regulator fault finding chart (Section 5.7.2) for fault diagnosis.
Check the 13.8V (TP601) and 9V (TP602) supplies at their test points in the regula-
tor compartment with a DMM.
Check the 5V (TP604) and 20V (TP603) rails at their respective test points in the
regulator compartment.
Check that Tx-Reg. (TP305 in the exciter compartment) comes up to 8.8V when the
exciter is keyed.
Check the +5V digital regulator output (TP607 in the regulator compartment).
T856 Only: Check the 9V supply (IC370 pin 1) with a DMM.
Check for short circuits.
5.4.2 VCO Locking
Key the exciter.
Using a DMM, monitor the VCO control voltage on the long lead of L1 on the
VCO PCB.
If the synthesiser is locked and the VCO aligned, the voltage at this point should
be between 3 and 16V.
If the VCO is not locked, refer to the synthesiser fault finding chart (Section 5.7.3).

Tait T850 II Series Specifications

General

Brand	Tait
Model	T850 II Series
Category	Accessories
Language	English