Thanks for reading this posting.

I need some help from experts. My TS-830S stopped transmitting. It was
working fine until few months ago, then it shows a little delay on transmit.
When I pressed PTT, the first couple of seconds get cut off in the
beginning. After this point, everything seems working fine with good power.
I thought it was caused by faulty driver or final tubes, so I replaced all
three tubes. After I replaced all three tubes, the symptom disappeared but
I ran into a new problem.

I was turning the TC1 trimmer to neutralize the final, and I saw a small
sparks and smelled some burn. From this moment, no output power. When I
turn the meter to Ip, it goes to infinite on transmit even if I try to
adjust it using the BIAS pot. The voltage on the plate seems OK.

Does anyone know what the problem might be? I think one of resisters or
caps got burned but I can't see it since the board is under the chassis.
Should I take it apart and check it out?

Any input will be greatly appreciated. Thanks.

Chris VA3UT

You may have smoked the 20 ohm 1/2 watt final cathode resistors R2, R3, R4,
R5. This can give the symptoms you describe, no output and pegged plate
current reading. The plate current is not actually high, but the meter
reads the voltage across the cathode resistors to display current, if they
are open it reads very high. Be sure to use a non-metalic adjusting tool
around the finals.

Good luck, the TS-830 is a fine old radio, I have had mine for 20 years and
it is still doing its job for me.
-KJ4DU


"Chris" wrote in message
.. .
Thanks for reading this posting.

I need some help from experts. My TS-830S stopped transmitting. It was
working fine until few months ago, then it shows a little delay on
transmit. When I pressed PTT, the first couple of seconds get cut off in
the beginning. After this point, everything seems working fine with good
power. I thought it was caused by faulty driver or final tubes, so I
replaced all three tubes. After I replaced all three tubes, the symptom
disappeared but I ran into a new problem.

I was turning the TC1 trimmer to neutralize the final, and I saw a small
sparks and smelled some burn. From this moment, no output power. When I
turn the meter to Ip, it goes to infinite on transmit even if I try to
adjust it using the BIAS pot. The voltage on the plate seems OK.

Does anyone know what the problem might be? I think one of resisters or
caps got burned but I can't see it since the board is under the chassis.
Should I take it apart and check it out?

Any input will be greatly appreciated. Thanks.

Chris VA3UT

hi,

You have rec'd good info, here is another
resource, come on over and join other
ts-5xx ts-8xx users !

http://groups.yahoo.com/group/TS-520_820_530_830/

ed