Web Page            http://www.kb2ljj.com                           Email                   webmaster@kb2ljj.com 

TH-205 Protection Fuse Replacement

When a plug other than the PG-2V or PG-3C is inserted into the DC IN jack, the ground side of the jack may not disconnect. This may cause the external DC power to be supplied directly to the internal battery which results in overheating the battery and blowing the fuse. To protect the battery, replace the fuse with a protection diode, part number ERB83-004.

Note models with serial numbers greater than 801XXXX allready incorporate this diode as D16.

This modification may be performed under warranty.
Time required for this change is 1/2 hour or less.

TH-215 to TNC


The hook-up of a th-215A to my pac-comm tiny 2 tnc was very easy. There are no components involved in the connection. All you need are two phone plugs: 1 sub mini, and 1 stereo(3 conductor) mini.
Both available from radio shack,two to a pack.
if you have a kenwood speaker mike, then the instruction sheet will contain a drawing showing the basic connecting lines. if not, heres how its done:
The sub-mini is the speaker plug. The center pin goes to the speaker pin on the 5 pin din on the tnc, the shaft is the ground.
On the mini stereo plug, you dont use the center pin, just the two shaft connections. the short shaft goes to mike, the long shaft is the push to talk......thats it, four wires to the connector that goes to the tnc plug, and youre in business!!

One very very important thing-----always make sure that all battery save functions on the handy talkie are off. if it isnt, a slight delay in receiving will cause retrys from the station sending to you, and will delay packet reception at your end. please make careful note of this. Any questions, reply to K2JOV, HARRY, at N2ELC-4 BBS in n.j......good luck!!

1. Remove two screws from belt clip
2. Remove 4 screws from back of radio
3. Slide front assembly off
4. Locate set of 4 jumpers:
   

                                 (top front inside)
                     +--------------------------------------+
                     |                                      |
                     |                                      |
                     |         +--------+                   |
                     |         |        |                   |
                     |         |        |                   |
                     |         +--------+                   |
                     |                                      |
                     |                      +--------+      |
                     |                      |        |      |
   J4: intact        |           J4 o---o   |        |      |
   J3: cut           |           J3 o) (o   +--------+      |
   J2: cut           |           J2 o) (o                   |
   J1: cut           |           J1 o) (o                   |
                     |                                      |
                     |                                      |
                     |                                      |
                     |                      SPKR            |
                     |                                      |
                     |                                      |
                     |             mic                      |
                     |                                      |
                     +--------------------------------------+
   

5. Reassemble radio.
6. Reset microprocessor: Turn radio on while simultaneously pressing both _F_ key and _ENTER_ key. 
   

   ---

   Newsgroups: rec.ham-radio
   Subject: Re: Kenwood TH-215A no audio problem
   Organization: Hewlett-Packard Co., Corvallis, OR, USA
   
   PROBLEM:
   

   >In a sample population of about 60 amateurs in this town, three of us
   >own Kenwood TH-215A HT's, all purchased separately at different times
   >from different sources....
   
   >ALL THREE have developed an audio problem in the last eight months:
   >the audio (both from the microphone and from the keypad) simply
   >disappears at unpredictable intervals.  And all three can be "fixed"
   >by WHACKING the HT with the palm of one's hand--until it happens again.
   

   A POSSIBLE FIX:
   
   You guys may be in luck, since I fixed mine -- I have the service manual and decided to jump in (I had upgraded the software and you have to pull the unit completely open to do it -- ). Anyway, I was using the rig one day and the next -- no audio -- just a slight noise that appeared to be white noise from the final audio buffer. When plugging in the speaker mike -- same problem. Touch the TTPAD and get your ears blown away -- I think beep also worked. Kenwood had no knowledge of previous problems.
   
   I had to rig-up a jumper ribbon cable so I could lay the rig out for testing and immediately checked the input audio to the volume control.
   No problem -- but there was nothing coming out the other side. I jumpered the pot (i.e. simulate pot max volume) and my ears were hurting. Upon removal of the pot I found a crack on the ALPS pc board that has the leads mounted to it. Apparently, I must have hit the volume control pot the previous day and cracked the pot trace (again this trace was part of the pot not the rig pcb). I had noticed when I disassembled the unit that there was no nut on the pot to hold it in place (none on the squelch either). The volume pot is right at the edge of the unit and is the most likely knob to get hit.
   
   When parts arrived, it came with a nut so I installed it to help prevent this problem in the future -- no problems since.
   
   I think the switched volume pot cost $4.95 + $3.00 shipping.
   I also picked up a set of backcase screws -- very small heads but very long screws to replace my old ones -$.05 - Make sure you have a "good" screwdriver that really fits.)
   
   All these problems sound like the same thing. I have never had any problems with my rig, and I bought one of the first ones out. (Hence, the software update to give me the ability to lock out memory channels during scan.)
   

   ---

   
   TH-215 jumper modification
   
   The Th215 tranceiver can be modificated by setting jumpers in the following positions:
   

     J1  J2  J3  J4      RX           TX      step     DTMF     TONE
   __________________________________________________________________________
   
     1   1   1   1    144-146Mhz     <==      20k       YES      38 tone
   
     1   1   1   0    141-163Mhz    144-146    5k       YES      38 tone
   
     0   1   1   1    144-146Mhz     <==       5k        NO      TONE1750hz
   
     1   0   1   1    144-146Mhz     <==       5k        NO      1750 hz
   
     0   1   1   0    144-146Mhz     <==      12.5k      NO      TONE/1750hz
   
     1   0   1   0    144-146Mhz     <==      12.5k      NO      1750 hz 
   
     0   0   1   1    144-148Mhz     <==       5k       YES      38 tone
   
     1   1   0   1    141-163Mhz    144-148    5k       YES      38 tone
   
     0   1   0   1    141-163Mhz    141-151    5k       YES      38 tone
   
     0   0   0   1    141-163Mhz     <==       5k       YES      38 tone
   
     0   0   1   0    134-148Mhz     <==       5k       YES      38 tone
   
     1   0   0   1    154-174Mhz     <==       5k       YES      38 tone 
   

   0 = No jumper
   
   1 = jumpered

      Email                webmaster@kb2ljj.com

 73's
   John Ribeiro
             KB2LJJ