![]() | SB-831 |
Service Bulletin | Amateur Radio Division |
Subject: TS-120S - Ant Input Transformer Replacement | Date: August 12, 1980 |
TS-120S transceivers subject to strong static fields, high RF or other similar high current atmospheric discharges may suddenly exhibit low RX sensitivity on all bands. Tx will not be affected. Suspect T1 on the RF unit X44-1260-01.
When replacing T1, L34-0696-35, check that the value of C20 is 33pf.
Early units may have a l5pf for C20, and may have T1 as
L34-0696-05. In either case, replace the transformer with a
L34-0929-15. If C20 is 15pf, replace it with a 33pf capacitor.
Since T1 is a broadband transformer, no adjustment is necessary.
Part | Old Part No. | New Part No. | Description |
---|---|---|---|
T1 | L34-0696-05/L34-0696-35 | L34-0929-15 | Antenna coil |
C20 | 15pf | CC45RH1H330J (33pf) | Capacitor |
In addition, add two 1S1587 diodes after the transformer as shown to further protect the receiver.