I have a Kenwood TS-520S that keeps blowing the 6 Amp line fuse in it.
My Bias control is set for 60ma idle current,
HV is right at 800V
SWR under 1.3:1
It tunes up fine and will run a QSO for about 30 Seconds (CW) then
POOF the fuse blows.
Blows the fuse when operating phone also.

One thing I did find is that the running plate current is a little
high, seems to be about 270-280ma when transmitting, but I can't find
a way to get it lower... adjusting the carrier all the way down has no
effect. rig is putting out 100W on 20 meters

any tips greatly appreciated

Tnx & 73

The plate voltage is low which tells me one of the main filter caps is
leaking. It will short and blow the fuse.

--
Clif Holland, KA5IPF
AVVid
Authorized Kenwood and Icom Amateur Service
www.avvid.com
1-800-214-5779


"George" wrote in message
om...
I have a Kenwood TS-520S that keeps blowing the 6 Amp line fuse in it.
My Bias control is set for 60ma idle current,
HV is right at 800V
SWR under 1.3:1
It tunes up fine and will run a QSO for about 30 Seconds (CW) then
POOF the fuse blows.
Blows the fuse when operating phone also.

One thing I did find is that the running plate current is a little
high, seems to be about 270-280ma when transmitting, but I can't find
a way to get it lower... adjusting the carrier all the way down has no
effect. rig is putting out 100W on 20 meters

any tips greatly appreciated

Tnx & 73

(George) wrote in message . com...
I have a Kenwood TS-520S that keeps blowing the 6 Amp line fuse in it.
My Bias control is set for 60ma idle current,
HV is right at 800V
SWR under 1.3:1
It tunes up fine and will run a QSO for about 30 Seconds (CW) then
POOF the fuse blows.
Blows the fuse when operating phone also.

One thing I did find is that the running plate current is a little
high, seems to be about 270-280ma when transmitting, but I can't find
a way to get it lower... adjusting the carrier all the way down has no
effect. rig is putting out 100W on 20 meters

any tips greatly appreciated

Tnx & 73
George, It is possibly a tube heating up and shorting.. you could
remove the top cover and the cover from HV cage where you can see the
6146 tubes. if they get red and blow the fuse. get a new set of 6146s
...make sure that you tune up as per instructions..run no more than 200
ma. PA plate current..if you cannot reduce the plate cur with the load
control then you have another problem..If I can be of help let me know
OK tnx Harold W4PQW