(Fwd) Re: [Kenwood] TS-520SE receiver brain teaser

2004年2月26日 10:47:29 +0800

Tim,
I agree with Gary at least so far as my schematic of the TS520S (not 
E) is concerned. There is an RF choke from antenna connector to 
ground when in the transmit condition.
 In receive there is a DC path to ground from the antenna connector 
via the link coupling coil in the receive path. This path is disconnected 
from the main connector if you select Ext Rec Ant or Xverter ON so the 
short should disappear if so switched which might be some sort of 
quick test... 
All this applies to the TS520S so a word of caution as the TS520SE 
may differ a little.
73...Don VK6HK
Tim -
I don't have a schematic for the TS-520SE, but many 
transmitters _DO_ show a DC short across the antenna 
connector. For quite some time, an RF choke has been 
connected from the antenna output lead to ground. It can 
serve several purposes, one is to bleed off static charged 
accumulated on ungrounded antennas. Another is to short the 
power supply, (or at least send up a smoke signal,) if the 
plate blocking capacitor should short.
So before you turn yourself inside out getting in there, you 
might want to look at a schematic to see if this choke is 
present. For example, the TS-830 DOES have such a choke, 
(470 uHy) and would show only a very few ohms to ground.
73, Garey - K4OAH
Atlanta
Tim Billingsley wrote:
> Therein lies the delima ...
> Now I must acquire sufficient Light, Magnification, and intestinal
> fortitude to attempt removing the power supply to gain access to the
> SO-239. I already pulled the covers off last weekend in an attempt
> to see what the problem may be ... then resorted to the schematic
> ... must have misread it as well .... *sigh*
>> Darrell Drake wrote:
>>> Tim...
>> There should NOT be a dead short between the centre conductor
>> and 
>> ground
>> of the chassis mounted SO-239, make and model of radio 
>> notwithstanding. It
>> appears that there is a short inside the radio (or a bad SO-239
>> jack) Cheers and Good Luck... Darrell, VA3DG/VE3DDG
>>>>>> Tim wrote....
>>>>>>>>> I tested the connection on the radio and it shows for
>>> lack of a better VOM a dead short,
>>>>>>>- - -
Your moderator for this list is:
Larry Wilson KE1HZ [email protected]
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