KENWOOD SERVICE BULLETINS BY NUMBER 11/21/89 SB # MODEL TITLE 1 (OBSOLETE) 2 TS-520 NOVICE OPERATION - 75 WATTS 3 QR-666 VFO STABILITY 4 TS-520 AM BROADCAST INTERFERENCE 5 TS-700A REPEATER MODIFICATION (EUROPE) 6 T-599D CHAIN DRIVE MODIFICATION 7 T-599A/D SERVICE NOTES 8 R-599A/D SERVICE NOTES 9 TS-820S SPEECH PROCESSOR ALIGNMENT 10 TR-7400A FINAL UNIT ARCING 11 TR-2200A ANTENNA ADAPTER 12 TS-820 AUX BAND INSTALLATION (RX ONLY) 13 TS-820 RIT MODIFICATION 14 TS-820 MICROPHONE INPUT ATTENUATOR 15 VOX-3 SENSITIVITY AND DELAY 16 TR-8300 ALIGNMENT 17 T-599D REDUCING 120HZ HUM 18 TR-7400A SERVICE NOTES 19 DG-1 NEW DISPLAY TUBE 20 TS-700A SERVICE NOTES 21 TS-520 SERVICE NOTES 22 TR-2200A SERVICE NOTES 23 TR-7200A SERVICE NOTES 24 TS-820S SERVICE NOTES 25 DG-5 REPAIR 26 DG-1 SERVICE NOTES 27 TS-700A 9 VOLT REGULATOR REPLACEMENT 28 DG-5 REPAIR NOTES 29 DG-5 THEORY OF OPERATION 30 TS-820S GENERAL ALIGNMENT PROCEDURE 31 R-599A/D REMOVING CB BAND 32 TR-7400A CHANGES IN PD UNIT 33 RM-76 FREQUENCY ERROR WITH TR-7600/7625 34 TR-7400A METER LAMP LONGER LIFE 35 MC-45 MODIFICATION FOR USE WITH TR-7400A 36 TS-180S DFC HUM WITH PS-30 37 TS-120S VOX OPERATION PICK-UP TIME 38 TS-120S FINAL TRANSISTOR REPLACEMENT 39 TR-7600/7625 ALTERNATOR WHINE 40 TS-120S ANTENNA INPUT TRANSFORMER REPLACEMENT 41 BS-8 ALIGNMENT WITH TS-180S 42 TS-180S IF #2 OUTPUT LEVEL CHANGE 43 TS-520S -6VDC SUPPLY FAILURE 44 TS-120S/180S PHONE PATCH TERMINAL ADDITION 45 TR-7600/7625 AUDIO TONE ON TX 46 TS-520 (S) CW FREQUENCY SHIFT 47 TS-180S INCREASE OF RX AUDIO OUTPUT 48 TS-120S HUM IN SSB TX 49 UHF/VHF OPTIONAL FILTER LIST 50 TR-7600/7625 OPTIONAL CERAMIC FILTER 51 TS-120S FINAL PROTECTION 52 TS-520 (S) BS-5 SWEEP INTERFERENCE 53 DG-1 STANDARD SERVICE 54 DG-5 STANDARD SERVICE 55 TS-180S LOW 40 MTR ALC 56 TS-180S DFC 57 SM-220 SHIELD INSTALLATION 58 TR-2400 TONE ENCODER RFI 59 RM-76 BATTERY BACK-UP POWER 60 TS-120S REPAIR NOTES 61 TS-180S TROUBLE SHEET 62 DK-520/DG-5 USE WITH TS-511/TS-900/T/R-599 63 TS-520 IF OUT FOR SM-220 64 TS-120S FULL CW OUTPUT IN SSB MODE (USE SB-944) 65 TR-7600/7625 RF POWER MODULE RETURNS (OBSOLETE) 66 SM-220 FEEDBACK FROM BS-8 67 TS-180S DFC INSTABILITY 801 TS-120S TX OSCILLATION (USE SB-844) 802 RM-76 MICROPROCESSOR FAILURE 803 TS-180S CW DELAY DURING VOX MEMORY OPERATION 804 TR-7625 INTERMITTENT TX 805 R-1000 MUTING 806 TR-7600/7625 MEMORY BATTERY BACK-UP 807 TR-2400 OPTIONAL CHARGE INPUT PROTECTION 808 TR-2400 OFFSET FAILURE 809 TR-2400 UNWANTED NOISE: TONE OR BURST AT TX 810 TR-2400 DISPLAY OR KEYBOARD TROUBLE 811 TR-2400 RX LOW, INTERMITTENT, OR DISTORTED 812 TS-520/820 CW FILTER SELECT CONTROL 813 R-1000 AGC, AM BANDWIDTH CHANGES 814 TR-2400 UNLOCK 815 TR-2400 PULSE NOISE 816 TS-120S BAND PASS FILTER CHANGE 817 TS-180S USE WITH A LINEAR AMPLIFIER 818 TR-2400 SCRATCHY TX 819 TR-2400 VOLUME CONTROL REPLACEMENT 820 TR-7625 FINAL MODULE REPLACEMENT 821 TS-120S TX OSCILLATION (USE SB-844) 822 TR-2400 BATTERY CHARGER FAILURE 823 R-1000 RF ATTENUATOR 10 DB STEP OPTION 824 TR-9000 CW/SSB TX INSTABILITY 825 TR-9000 TX PULSE NOISE IN SSB 826 TR-7625 HYBRID AMPLIFIER MODULE SUBSTITUTION 827 TS-120S VFO STABILITY 828 TR-7800 TONE PAD CONVERSION FOR 4TH COLUMN FUNCTION 829 TR-7800 LOSS OF MEMORY 830 TR-2400 TX NOISE 831 TS-120S ANTENNA INPUT TRANSFORMER REPLACEMENT 832 TS-120S FULL CW OUTPUT IN SSB MODE (USE SB-844) 833 TR-7800/9000 OPTIONAL CERAMIC FILTERS 834 TR-7800 PULSE NOISE 836 TR-7800 OPTIONAL CONTINUOUS CHARGE FOR INTERNAL BATTERY 837 TS-830S OPERATION ON 240V AC 838 VFO-230 OPERATION ON 240V AC 839 TS-180S VFO STABILITY 840 TS-830S FREQUENCY SHIFT 841 TR-7800 CLOCK AND DISPLAY FAILURE 842 DS-2 REPLACEMENT FOR DS-1A 843 TR-8400 SUB-AUDIBLE ENCODER INSTALLATION 844 TS-120S TX OSCILLATION 845 TR-8400 RX INTERNAL SPURIOUS SIGNALS 846 TR-7850 RF LED METER (LOW READINGS) 847 TS-830S LOW VOLTAGE SUPPLY OPTIONAL IMPROVEMENTS 848 TS-530S LOW VOLTAGE SUPPLY OPTIONAL IMPROVEMENTS 849 TR-9000 TRANSMITTER SIDEBAND CARRIER BALANCE 850 TS-180S LOW PASS FILTER OPTIONAL CHANGES 851 TS-830S NOISE BLANKER OPTIONAL IMPROVEMENTS 852 MC-46 DTMF OPERATION WITH OLDER EQUIPMENT 853 TR-8400 TRANSMITTER FREQUENCY RESPONSE VOICE OR DTMF 854 TR-7730 TRANSMITTER FREQUENCY RESPONSE VOICE OR DTMF 855 TR-8400 TRANSMIT DELAY TIME 856 TS-660 MICROPROCESSOR LATCH-UP 857 TS-830S TRANSMITTER "TALKBACK" 858 TR-2500 RX IMD IMPROVEMENT 859 TR-9000 TEMPERATURE STABILITY IMPROVEMENT 860 TR-7800/7850 MEMORY CH. 7 INDICATOR ERRATIC 861 TR-7800/7850 MEMORY IMPROVEMENTS 862 VFO-120 DIAL LAMP SWITCHING CIRCUIT 863 TS-930S INCORRECT LINE VOLTAGE SETTING (OBSOLETE) 864 SMC-25 MODIFICATION FOR USE WITH THE TR-2400 865 TS-430S 500KHZ HETERODYNE 866 TS-930S CW HETERODYNE TONE 867 TS-930S SSB TX TONE QUALITY 868 TS-930S LOW RX SENSITIVITY 869 TS-930S PLL UNLOCK 870 TR-7930/7950 RX INTERFERENCE 871 TR-9130 LOW DRIVE LEVEL 872 TS-930S CW PITCH TONE SHIFT 873 TS-930S CW VBT 874 TS-930S RF FEEDBACK 875 TS-930S RX AUDIO OSCILLATION 876 TS-930S RF FEEDBACK INTO MIC CIRCUIT 877 AT-930 SERVICE NOTES 878 TS-530S IF UNIT Q2, Q7 PROTECTION 879 TS-930S INCREASED TX AUDIO 880 TM-201/401 INCREASED TX AUDIO 881 TS-930S POWER SUPPLY SURGE PROTECTION 882 TS-430S NOTCH CONTROL 883 TS-430S AM WIDE/NARROW FILTER SELECTION 884 TS-930S 15 MTR INTERNAL BEAT NOTE 885 TS-430S RECEIVER INTERNAL BEAT 886 TS-930S INTERMITTENT TX POWER OUTPUT 887 TS-430S NOISE BLANKER IMPROVEMENTS 888 TS-430S INTERMITTENT PLL UNLOCK IN FM/AM 892 TM-411 LOW/NO RECEIVER SENSITIVITY 893 TS-930S NOISY POWER SUPPLY FAN 895 TS-430S PLL UNLOCK AT HIGH TEMPERATURE 896 TS-940S LCD CLOCK DISPLAY ERRATIC OPERATION 897 TM-211/411 AF GAIN CONTROL PART CHANGE 900 TS-940S PLL UNLOCK 901 TR-2600A PLL UNLOCK (TROUBLESHOOTING) 902 TS-430S LOW/INTERMITTENT RX 903 TR-2600A PLL UNLOCK 904 TM-2550 DCL CALL SIGN DATA 905 COAX CABLE WITH PLUG LIST 906 TM-2570 LOW TX POWER OUTPUT 907 TS-940S ANTENNA TUNER RELAYS 908 TS-940S PLL UNLOCK 909 TS-940S AVR UNIT CAPACITOR CHANGE 910 TS-940S AGC CIRCUIT IMPROVEMENTS 912 TS-940S TRANSMITTER HUM IN SSB 913 TS-940S SIGNAL TO NOISE RATIO IMPROVEMENT 914 HMC-1 NOT TO BE USED WITH TH-205ST/TH-215A 916 PS-50 IMPROVED VOLTAGE SURGE PROTECTION 917 TS-940S VCO CARRIER TO NOISE RATIO IMPROVEMENTS 918 TS-940S SQUELCH SWITCHING NOISE 919 R-5000 NO FREQUENCY CHANGE THROUGH COMPUTER INTERFACE 920 TH-205/215 PROTECTION FUSE REPLACEMENT WITH DIODE 921 TS-940S SSB TALK POWER IMPROVEMENT 922 RC-10 HANG UP TIME/TIMEOUT TIMER SETTINGS 925 TM-3530A NOISY TRANSMIT 926 TW-4100A REPEATER STOP SCAN ON THE UHF BAND 927 RC-10 ALTERNATOR NOISE 928 TS-140S INTERMITTENT LOSS OF TRANSMIT POWER 929 TS-140S MOMENTARY TRANSMISSION WHEN VOX IS TURNED ON 930 TM-721A MICROCOMPUTER LOCK-UP 931 TM-721A LOW/NO VHF TRANSMIT POWER 932 TH-25/45 W/TSU-6 TONE ALERT IMPROVEMENTS 933 TM-221A NO TX IN HIGH POWER DUE TO VOLTAGE DROP 934 TM-221A FINAL MODULE HINTS 935 TM-321A LOSS OF TX AUDIO WITH MC-48B 936 TM-721A S-METER DEFLECTION DUE TO PULSE NOISE 937 TM-721A AF PA WHITE NOISE WITH MC-48B 938 PS-430 VOLTAGE INCREASE WITH TH-205/215 939 TH-25/45 AUTOMATIC POWER OFF FUNCTION 941 SERVICE MANUAL RX SECTION LEVEL DIAGRAMS 942 SERVICE MANUAL TX SECTION LEVEL DIAGRAMS 944 TH-205/215 VOLUME/SQUELCH CONTROL IMPROVEMENTS 945 TH-205 SIGNAL TO NOISE RATIO IMPROVEMENTS 946 TH-215/415 TX SIGNAL TO NOISE RATIO IMPROVEMENT 947 TS-440S OPERATION WITH THE MC-85 948 TS-440S NOTCH FILTER LOW FREQUENCY IMPROVEMENTS 949 TS-440S PROTECTING Q33 950 TS-440S CASE SCREWS BINDING IN THE HEAT SINK 951 TS-940S ERRATIC DISPLAY (REMOVE THE SOCKET) 952 TS-440S INTERMITTENT OPERATION (REMOVE THE SOCKET) 953 MC-55 CHANGE IN MIC ELEMENT (T91-0328-08) 954 TS-820S TA7201P SUBSTITUTION PARTS KIT