[Kenwood] TS-120S display problem

Wed, 03 Jul 2002 18:02:40 -0500

Pretty simple binary stuff Jose.  I am assuming your example of the 25khz part is 
not relavent, i.e. 3513KHz is also displayed 3.113KHz.  That being true then - 
Expect 5 (101) gets 1 (001), expect 6 (110) gets 2 (010) and lastly expects 7 (111) 
gets 3 (011).  Notice the pattern.  The third bit is always stuck zero.  Looking at 
my TS-120 schematic I see that the display itself is a scanning type.  Thus, they 
are really only lighting one display digit at a time and scanning through them one-
by-one. plus, they drive the individual segments that make up the numbers.   The 
scan is so fast that you don't notice it with the naked eye.  This is a very common 
way of running multi-digit display as it saves on electronics component count and 
complexity.  However, it does make it a bit more difficult to diagnose with out a 
good scope or better yet a logic analyzer. So it wouldn't be likely that it would 
be the display itself nor the immediate driver chips.

First things first though.  Try reseating the connectors and any jumpers on the 
Counter unit boards first.  This board shows alot of jumpers on the schematic, but 
I'm not sure if they are soldered in or not. Next try and take a non-metalic 
object, like the back end of a ball-point pen, and tap around the board.  If it's a 
bad solder joint you might be able to pin point it that way.  Most often these are 
the most common problems.

From my quick look at the schematic it appears the MHz digit are fixed set by the 
band switch telling the counter/display board which band it's on.  The KHz (100KHz 
and down) digits are an actual frequency counting of the signal from the VFO unit 
(thus I'm sure your problem exists on all bands right?).  As the VFO always tunes 
from 5.5 to 6 MHz.  If it's an IC most likely part of the divider chain IC8 thru 
IC12.  However, let's not jump that far ahead.  try the easy stuff first.

Good Luck,

Don N9OO

On Wed, 3 Jul 2002 19:16:51 -0300, Jose B.da Silva wrote:

>I did a mistake.
>Please note that when in 3.525.0 the display is in 3.125.0, when in 3.625.0
>the display is in 3.225.0 and when in 3.725.0 the display is in 3.325.0.
>This is just an example.
>
>TNX - Jose, PY5CEK
>----- Original Message -----
>From: Jose B.da Silva <[email protected]>
>To: <[email protected]>
>Sent: Wednesday, July 03, 2002 8:18 AM
>Subject: [Kenwood] TS-120S display problem
>
>
>> Hello to all!
>>
>> A friend of mine has a TS-120S with an interesting problem.
>> When in 3.525.0 the display indicates 3.325.0. When in 3.625.0 the display
>> indicates 3.425.0. When in 3.725.0 the display indicates 3.525.0. When in
>> 3.825.0 it is OK.
>> The same in 28.5 MHz band.
>> In the other bands, the problem starts after X.399.9. For example, 7.399.9
>> is OK in the display. In 7.400.0 the display goes to 7.000.0.
>> The rest of the display is OK. The problem is only with the hundred kHz
>> digit.
>> The problem seems to be related with the binary code. Which part do I have
>> to look in the counter? Any ideas?
>>
>> 73 from Jose, PY5CEK
>>
>> - - -
>>
>> Your moderator for this list is:
>> Larry Wilson KE1HZ [email protected]
>>
>> _______________________________________________
>> Kenwood mailing list
>> [email protected]
>> http://mailman.qth.net/mailman/listinfo/kenwood
>
>- - -
>
>Your moderator for this list is:
>Larry Wilson KE1HZ [email protected]
>
>_______________________________________________
>Kenwood mailing list
>[email protected]
>http://mailman.qth.net/mailman/listinfo/kenwood

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