My loaner HW-101 has an oscillation problem on USB on all bands. Info I found online suggested loose board screws t the chassis. I checked and found a bunch of loose ones and all are tight now. My diagnostic skills aren't what they should be. I usually build stuff based on an idea or somebody else's design and I am good at modifying and repairing electronic stuff (based on others published information).
Anybody have any ideas?
Last edited by KA9MOT; 12-10-2011 at 10:37 AM.
"One man with courage makes a majority." ~ Andrew Jackson
Steve KA9MOT
Macomb, IL
Dunno. But here's some linkies...
http://www.ki6yfq.com/projects/heath...ansceiver.html
http://nrwilliamson.tripod.com/Hw101.pdf
http://www.davemorris.com/dave/wb8jkr.jpg
http://www.qsl.net/k5bcq/102/102.html
http://ww_heco.home.mindspring.com/heco_fix.html
http://m0msx.webs.com/heathkitequipment.htm
"Where would we be without the agitators of the world to attach the electrodes
of knowledge to the nipples of ignorance?" ~ Professor "Dick" Soloman
Does the oscillation happen with the mic gain all the way down?
If it's a war on drugs, then free the POW's.
Yes, with the mic gain all the way down, with mic and with-out. When keyed she oscillates and only on USB.Originally Posted by W1GUH
Last edited by KA9MOT; 12-11-2011 at 06:05 PM.
"One man with courage makes a majority." ~ Andrew Jackson
Steve KA9MOT
Macomb, IL
Some of this I've all ready seen. All helpful and all a good read! Thanks!
"One man with courage makes a majority." ~ Andrew Jackson
Steve KA9MOT
Macomb, IL
Is the carrier balance adjusted?
We never had weather like this before they started messing around with that internet stuff.
Hmmm...only USB? Not LSB? Interesting. Gotta be a clue there, somewhere. Will be thinking about it.
Oh, and has it been determined if it's oscillation or just too much carrier? Sorry if I'm suggesting things that you'ver already tried...just thinking off the top of my head. Or maybe off the bottom of my....
Or does that mean only when it's plugged into your computer? Just coudn't resist! Sorry about that!
If it's a war on drugs, then free the POW's.
I'm looking at the schematic, on the left, about half way down around a mode switch wafer that switches between two crystals. Have you checked that the USB crystal is there, is good, and the connections are in good shape? The schematic I'm looking at is not so good, can't read which xtal is USB. Looks like the only RF difference between USB and LSB. The wafer above might be suspect, too.
No, but wait...this is only on the upper bands? Do I remember that correctly?
Does USB work on the lower bands?
Sorry about my OF memory!
Good luck & have fun!
Last edited by W1GUH; 12-22-2011 at 11:56 PM.
If it's a war on drugs, then free the POW's.
Just bumping this up so 'MOT can see it. Cheers!
BTW...re: only upper bands....yea, even then. Could be if there's something funky in that sideband selection scheme, the feed back could only be strong enough at the upper frequencies? In any event, it's easy to check. What happens on the lower freqs. on USB?
If it's a war on drugs, then free the POW's.
Thanks all! I haven't had the time to work with this rig for a while (needed to take a break anyway). Paul, I really appreciate the time and thought you've put inot this. My problem is on all Bands and only in USB Mode.
The guy who owns the rig said it worked FB at his place, and I have ruled out RF in the shack, Mic problems and all of the basic stuff. I running on the assumption that FedEx may have been less than careful with it, and have been looking at solders and grounds.
John, the carrier balance does seem to be adjusted, but I am not sure how to test it. There are some modifications to the circuit (regular shaft style pot soldered directly to the board replaces the stock board mounted pot) and all of the solders on this thing look really poor.
"One man with courage makes a majority." ~ Andrew Jackson
Steve KA9MOT
Macomb, IL
Posting Permissions
Reply With Quote