[Heathkit] HW-101 low output on 80 & 40 m

[Chris Codella, W2PA]

Gil,

Sometimes DC voltage measurements won't tell you what's wrong.

First, are you sure that the 7 watts you're measuring is going out on 80 
and 40?  If so (using a counter or another receiver), then the problem 
likely is in the final stage.  If not, the problem could be in an 
earlier transmitter stage, but I'm guessing it's actually 7W on 40 and 80.

As you change bands there are only a couple of components that are used 
on 80 and 40 that are also not in play on the other bands.  C929 for 
instance.  It's a 100pF capacitor located underneath the final cage 
connected between a ground lug and a terminal from the final loading 
capacitor poking through a hole in the chassis.  Check that one and make 
sure it's not fried or shorted or is otherwise disabled.

Also C803 meets the criteria (used on 80/40 and not elsewhere), but it's 
earlier in the driver stage and is less suspect.

Any other symptoms?

73,
Chris, W2PA



g wrote:

>After running my hw 101 for months flawlessly one day the output went from 100w to about 7 watts max on 80m & 40m, while 20m, 15 and 10m can still get up to 50 watts. Replaced all tubes including finals, changed a couple of resistors that were slightly out of range and still the same, I checked the voltages around the finals as compared to a working hw-101 and seemed ok as well.
>This one is over my head, cant figure why the output would drop on the lower portion of the bands.
>
>Any input appreciated....thanks....Gil n2wjw
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