Title: HW100 - osc changing mode switch Post by: kd1nw on November 19, 2017, 12:26:41 PM Hi Folks,
Sorry, I know its not an AM rig, I hope thats okay. When changing the mode switch between cw, usb, lsb there is a loud screeching oscillation. Trying to track it down but wanted to check to see if anyone has had this happen. Thanks Kevin Title: Re: HW100 - osc changing mode switch Post by: WD4DMZ on November 19, 2017, 07:16:17 PM I had issues with this switch on an HW100 and 101. Both had cracks in the wafer farthest from the front causing bad or intermitent contact. Found a switch someone was selling on a yahoo heathkit forum and used it in the 100. Works just fine now.
The HW100 wafer was clearly broken but the 101 was just enough of a hairline to allow the wafer to bow and bend. Look hard for cracks at 3 and 9 o'clock by the bolts holding the switch wafers together. Rich Title: Re: HW100 - osc changing mode switch Post by: kd1nw on November 20, 2017, 08:36:00 AM Hi Rich,
Thanks for the tip. I checked it out carefully and it looks okay When I remove V16 12AU7 the osc is continuous. Looks like I need to check things in this area 73 Kevin Title: Re: HW100 - osc changing mode switch Post by: kd1nw on November 23, 2017, 09:43:09 AM Hi All, AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
I found that touching either pin 8 or 9 on V13C stopped the problem. Strangely enough after a couple of times of doing that by touching R123 470 ohm the radio seems to be stable. I turned it off and on a few times letting cool down and so far so good. The receiver is working very good right now. I'll bet the problem reappears again but at least i know where to look. Maybe a flaky solder joint. Thanks 73 Kevin |