Kenwood TS-820 (TS 820 TS820) mods reviews software and diagrams

The following information is for the installation and alignment of the AUX band inthe TS-820. This extra band will be for receive only. Reference will be made to schematics and board layouts as shown in the Service Manual.

Installation

1. Remove the top and bottom covers.
   
   
2. Remove the Connectors from the PLL Assembly.
   
   
3. Remove the PLL assembly and set it aside.
   
   
4. Use the board layout of the Coil Pack to locate thepositions for the ANT and MIX coils on the Coil Pack.
   
   
5. Install the ANT and MIX coils on the Coil Pack.
   
   
6. Remove both covers from the PLL Assembly.
   
   
7. Remove the 5 Phillips head screws holding the PD Unit in the PLL assembly and carefully remove the PD unit.
   
   
8. Use the board layout of the PD unit to locate Q11.
   
   
9. Install R01, R02, C01, C02 and X01 as needed for the band desired.
   
   
10. Locate terminals AUX, B1, B2, B3, and B4 on the PD unit.
    
    
11. Install a jumper from the AUX terminal to the B terminal for the band desired. B1 is for 1.8 MHz to 9 MHz, B2 is for 10MHz to 18MHz, B3 is for 19MHz to 24MHz and B4 is for 25MHz to 30MHz.
    
    
12. Replace the PD unit in the PLL Assembly.
    
    
13. Use a 3mm nutdriver to remove the 4 hex nuts mounting the VCO unit in the PLL assembly, then remove the two phillips screws.
    
    
14. Carefully remove the VCO unit from the PLL assembly.
    
    
15. Use the board layout of the VCO unit to locate Q11.
    
    
16. Install C01, C02, C03, C04, C05, and T11 as needed for the band desired. Install T11 last.
    
    
17. Replace the VCO unit in the PLL assembly.
    
    
18. Install the connectors on the PLL assembly.

Alignment

1. Turn on the TS-820.
   
   
2. Tune VFO to 250.
   
   
3. Set band switch to AUX.
   
   
4. Set the TUN/NOR switch on the VCO unit to TUN.
   
   
5. Connect a frequency counter to terminals TP5 and TP6 on the VCO unit. (TP6 is ground).
   
   
6. Adjust T11 for a frequency of 9.08 MHz plus the lower limit of the band desired.
   
   
7. Connect a frequency counter to TP4 and ground on the PD unit, and verify the frequency of the reference oscillator. It may vary +/- 500KHz.
   
   
8. Return the TUN/NOR switch on the VCO Unit to the NOR position.
   
   
9. Turn off the TS-820S.
   
   
10. Replace the covers on the PLL assembly and reinstall it in the transceiver.
    
    
11. Replace the top and bottom covers on the TS-820S.

Caution Do no use magnetized tools when working on the PLL assembly. Beryllium tools would be better than ferrous ones. If the PLL assembly should become magenetized, use a bulk tape eraser on open core AC transformer to demagnetize it.