ARLA/CLUSTER: Rádios Jintong

[Paulo Mendes]

Bom fim de semana a todos..
 Durante uma pesquisa sobre os rádios Jingtong envontrei a mensagem que volu
colocar aqui. É util para quem não quer ser icomodado com o beep no arranque
do Rádio.

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Modding el Jingtong JT
208<http://radiosyelectronica.terapad.com/index.cfm?fa=contentNews.newsDetails&newsID=19512&from=list>
 [image:
Radio_150x41.gif]  Sunday, 20 May 07 - 07:30 PM (GMT +01:00)
By Fraser Cairns in Radios
VHF<http://radiosyelectronica.terapad.com/index.cfm?fa=contentNews.news&directoryId=5855>

Modding the Jingtong JT208 annoying start up tone


Here is the faboulous jt-208 transceiver (136-174 mhz) and it's mod to
cancel or reduce that annoying tone coming up at startup.

First of all, this beep removing operation is a little bit delicated so is
required a good practice with smt component soldering/desoldering. Do not
attempt to do it if you have never opened any electronic device.


About the opening of the case you can refer to this
link.<http://www.users.on.net/%7Eendsodds/dissem.htm>

Once you have removed the cover, you have to desolder the 2 ground link that
solder together the 2 board of the transceiver. Then, look at the other side
of the keyboard , you will see near the mic and the speaker hole, a little
smt transistor, which is used to amplify the beep signal coming from the pin
12 of the micro. Between that transistor and the mic there are an smt
capacitor and a resistor .

That capacitor bring the beep signal coming from cpu to the audio stage.To
reduce the tone volume you have to substitute that capacitor with one of
5Kpf better if smt package.


Be carefull in desoldering and soldering, use the minimal necessary
temperature to not brake the link. If you completely remove the capacitor
you will never hear any beep even from keyboard pressing. After that,
carefully reinsert the 2 connectors that link together the two boards and
re-solder the ground link to both side.

Re-assemble everything together with care, following the instuction given
from the same link given above.

Now try it, if you think it's still too hi, you can use any other capacitor
value between 1k and 10 kpf (Low- Hi volume beep).
Good luck.


73´s
Paulo Mendes - CT2HQT
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