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Modifications for the Kenwood TS-820

 

 

TS-820 Fix the problem with the display

 

 
 
Here is somthing you can do if your digital display on the kenwood ts-820 is giving you 
a problem.............. 

1.

 

Remove the counter assembly unit from the 820.  

2.

 

Remove both circuit boards from the counter assembly ( upper and lower boards 
).  

3.

 

Scrape away the varnish from the corners of the boards where the 
interconnecting screwes and spacers hold the boards into the case.  

4.

 

Reassemble the counter....  

That should take care of the problem.. 

New Display Tube for DG-1

 

 
 
The original display tube (LD-8109) used in the DG-1 digital display for the TS-820 
and TS-820S has been discontinued by the manufacturer. However, there is a 
replacement tube available. This tube is the LD-8135. It is not a direct replacement for 
the original tube. The leads come out of both ends of the display tube instead of just one 
as in the LD-8109. Therefore, it will be necessary to replace the complete display unit if 
the display tube fails. The part number of the new display unit is X54-1310-00. 
Please use this part number when ordering a replacement display unit. The new display 
unit is being installed in the current production of the TS-820S and DG-1. 
 
The new display unit (X54-1310-00) is a little more involved to install than the old one. 
The installation is as follows: 

1.

 

Remove the top cover of the TS-820 (or TS-820S) and set the unit on the bench 
so the front panel is facing you.  

2.

 

Remove the two screws from the original display unit (save them), unplug the 
display unit forom the counter assembly and remove the display unit from the 
transceiver.  

3.

 

Run the connector of the new display unit through the left bracket (from the 
center).  

4.

 

Gently (but firmly) push the right side of the display unit throught the right 
bracket. ( This is the most difficult part).  

5.

 

Gently push the left side of the display through the left bracket.  

6.

 

Install the screws from the old display in the mounting bracket of the new 
display unit and plug the connector into the counter assembly.  

7.

 

Turn on the TS-820 (or TS-820S) and make sure the display tube works 
properly.  

8.

 

Replace the top cover of the transceiver.  

 

TS-520, TS-820 CW filter select control

 

 

Summary of Contents for TS-820

Page 1: ...part number of the new display unit is X54 1310 00 Please use this part number when ordering a replacement display unit The new display unit is being installed in the current production of the TS 820S and DG 1 The new display unit X54 1310 00 is a little more involved to install than the old one The installation is as follows 1 Remove the top cover of the TS 820 or TS 820S and set the unit on the ...

Page 2: ...the FIX CH switch to 4 will operate the SSB filter 6 in CW mode TS 820S Series Transceivers 1 Similar to the TS 520 series a miniature SPDT toggle switch may be installed at the operators preference a the rear or on the obttom cover 2 The FIX CH switch or Digital Hold switch may be rewired to control the CW wide narrow function On the MODE switch S6 1 the SSB filter control is GREEN and the CW fil...

Page 3: ...eeded 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 lim...

Page 4: ... excess solder and while the screws are still hot turn the board upside down to allow the screws to fall onto the working surface Figure 3 10 Secure the new mounting screws with the two nuts that were removed in step 8 Figure 3 11 Install the heat sink and secure it with the two hexagon bosses from the kit Figure 3 12 Insert the wires from the new audio amplifier circuit board as shown in the diag...

Page 5: ... 2 is not changed when changing audio gen from 400 Hz to 2000Hz 4 Turn compression level to max CW Set audio gen to 1500Hz at 0 3 mv Adjust TC 3 and VR 6 carrier bal for speech proc for maximum level at TP 2 5 Set audio gen to 10 mv at 1500Hz Send Rec switch to send Adjust VR 7 comp level for speech processor so that the level at TP 2 is not changed when turning the processor on and off VR 7 shoul...

Page 6: ...s bad Q13 on FIX VOX unit 2 25 kHz calibrator will not zero Add 3 pf in parallel with TC 1 on the marker unit 3 Receiver sensitivity down Q2 on RF unit 9v on PD unit is shorted L 6 shorted to ground 4 Intermittant receive when moving set Check for touching terminals at final relay socket 5 No receiver or digital 14v wire pinched between DG 1 chassis and ground 6 Receiver sensitivity 40 db down Che...

Page 7: ... and LSB realign carrier unit per TKC specifications 18 No loading on 40 meters Foil path is open on RF coil pack 19 No tX when using send switch Bad R28 1K and Q9 on FIX VOX unit 20 Blows fuse Check for shorted C21 C22 100uf 500v 21 No drive no TX or bias Open screen resistor R6 470 ohm at rectfier unit 22 VFO intermittant Check for cold solder at VFO power plug 23 Audio distortion on TX with pro...

Page 8: ...hone input attenuator for TS 820 Author Trio Kenwood Communication inc Service bulletin no 14 16 2 1977 When using a high output microphone i e Shure 444 it is very likely that there will be distortion of the transmitted audio if the processor is used The reason the distortion occurs is because the processor is between the first microphone amplifier and the microphone gain control The installation...

Page 9: ...ay be done quicker This may be used in lieu of the alignment procedure in the Service Manual 1 Adjustment A V R unit X49 1080 00 a Adjust VR1 for 3 3V b Adjust VR4 for 9V 2 Adjustment V C O unit X50 1330 00 a PLace ST to TONE and connect a frequency counter tp TP5 b Adjust T1 T11 for proper frequency See table Note from www mods dk I m not sure about the data in the table are correct because the d...

Page 10: ... 1140 00 a Turn screen grid S G switch rear panel OFF heater switch ON b Center DRIVER control c Peak coil pack all bands for max reading on panel meter in TX and RX except WWV in TX Adjustment sequency Band VFO meate 1 1 8 100 2 3 5 250 3 7 150 4 14 175 5 WWV 0 15 0 MHz 6 21 225 7 28 5 500 5 6 Carrier point X50 1310 00 a Peak TX power in CW mode Then switch to LSB and modulate with Audio Gen A G ...

Page 11: ...and adjust TC4 to 451 9 200 Hz Adjust T11 T12 T13 for peak indication on COMP meter f Peak T14 by scope on TP2 g Turn processor full C C W and reduce A G gain to 1mv 400Hz h Adjust TC4 for max level n scope but at proper frequency 451 9 200Hz May adjust slightly off frequency if higher peak can be obtained i Sweep A G frequency from 400Hz to 2000Hz and check for balanced output on LSB and USB j CO...

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