HW-16 Troubles

[W5EUQ]

Hum like that sounds to me like the following........ typically is 
coming from bad filtering. You could put a scope on the B+ and you 
should see some pretty big AC...  The AC component on 300VDC should be 
less than a few millivolts.

First the B+ filtering caps are probably bad.  Then check the filtering 
at the audio amps too.  Any Electrolytic should be suspect.
When a radio's electrolytics  start going bad, typically it's best to 
replace ALL of them as the others are close behind for going bad.  And 
the work for replacing them all at once is less than opening it up 
several times, looking for the next bad cap and replacing it.
Hope this helps.   Bob W5EUQ  Tampa

Kenneth G. Gordon wrote:
My HW-16 has a LOT of hum, especially with the volume control all the 
way down, and so far, I can't figure out where it is coming from.

I have taken it down the the shop at work and intend to follow the hum 
around with a scope until I find it. I know it is not coming from any 
place ahead of the audio amp stages. If I yank the 12AX7 product 
detector/bfo tube, there is no change.

I also have terribly loud clicks in the headphones or speaker, but not 
on the air, when keying the darned thing.

I've tried several different methods for minimizing those, but have not 
yet succeeded in finding a proper cure.

I'm not even sure where it is coming from yet. I know at least one 
fellow attempted to add a limiter to the receiver to take that out, but 
it didn't work very well for me.

I wonder if anyone else has had either of these problems and fixed them?

Ken W7EKB

-----------------------------------------------------------
Products bought, sold or traded here is the responsibility of the
parties involved.  This list and the City of Tempe are not responsible
for losses or misrepresentations of any kind.  Buyer beware!

-----------------------------------------------------------
This list is a public service of the City of Tempe, Arizona
-----------------------------------------------------------

Subscription control - http://www.tempe.gov/lists/control.asp?list=HEATH
To post - HEATH at LISTSERV.TEMPE.GOV
Archives - http://listserv.tempe.gov/archives/HEATH.html