TS 520D question

[Dave S]

Hello All,
I have a Kenwood TS 520S that seems to have a problem in the idle current. I see that the idle currant should be 17 to 19 Ma currant on the IC meter with mic gain and carrier fully clockwise. on mine the meter goes all the way to the right off scale. when I put the meter switch in ALC the radio transmits just fine. Could there be a problem in the ALC circuit ? Sure could use some help here, Thank's
Dave

[Dave S]

Post by Dave S
Hello All,
I have a Kenwood TS 520S that seems to have a problem in the idle current. I see that the idle currant should be 17 to 19 Ma currant on the IC meter with mic gain and carrier fully clockwise. on mine the meter goes all the way to the right off scale. when I put the meter switch in ALC the radio transmits just fine. Could there be a problem in the ALC circuit ? Sure could use some help here, Thank's
Dave

I have the TS 420S, nor the TS 520s, my mistake, sorry.

[Scott Dorsey]

Post by Dave S
Hello All,
I have a Kenwood TS 520S that seems to have a problem in the idle curre=

nt. I see that the idle currant should be 17 to 19 Ma currant on the IC met=
er with mic gain and carrier fully clockwise. on mine the meter goes all th=
e way to the right off scale. when I put the meter switch in ALC the radio =
transmits just fine. Could there be a problem in the ALC circuit ? Sure cou=
ld use some help here, Thank's
I have the TS 420S, nor the TS 520s, my mistake, sorry.

Okay, I give up. What _is_ a TS-420S?

You might have a metering problem... you might also have totally ruined
finals.

If your output is one transistor or tube, the 'idle current' setting is
likely reading the voltage across the emitter or cathode resistor. You
can measure it too with a bench meter and compare it with the one on the
schematic. Check the value of that resistor too while you have it out,
because resistors will rise in value with time and heat and that will
cause that sort of symptom. Either the output is misbiased, failed, the
emitter/cathode resistor is bad, or some other resistance in the divider
network for the metering is bad.

The schematic will tell you everything that is going on, but I do not see
any TS-420S in any of my books.
--scott