17x Alive...Sorta


Tim Tyler II
 

Got my 17 meter 5watter finished. (Experimental version board.) Hooked up the battery to see R3 glow brightly and let out smoke. Unhooked battery. Turned off soldering station. Came upstairs to think about it.

Seems the only reason any current at all would be going thru R3 is if the rig is in transmit. Maybe tomorrow when I’m fresh I’ll pull the keyer IC and power it up again to see what else glows.

Tim NC0Q


 

R3 should never glow or burn up "if" associated parts around the driver transistor are correct. -Diz

On 6/18/21 11:31 PM, Tim Tyler II wrote:
Got my 17 meter 5watter finished. (Experimental version board.) Hooked up the battery to see R3 glow brightly and let out smoke. Unhooked battery. Turned off soldering station. Came upstairs to think about it.

Seems the only reason any current at all would be going thru R3 is if the rig is in transmit. Maybe tomorrow when I’m fresh I’ll pull the keyer IC and power it up again to see what else glows.

Tim NC0Q


Tim Tyler II
 

Yeah, I'll be having a look at which components around Q2 are incorrect when I get home from work later. The other thing that baffles me at the moment is why (if that's even what's going on) the rig is going into transmit the moment it's powered on. It was only powered up for a few seconds...but I heard no sidetone, no "5W" from the keyer....the only thing I saw/heard was R3 acting like an LED. I'm sure whatever it is will jump out at me when I get a chance to look at it later. This is what I get for stuffing the board willy-nilly and not building a stage at a time & testing as I go like I normally do. -Tim


Tim Tyler II
 

I got to thinking about it at work today and decided the only sensible cause for R3 flaming would be a short across collector and base pins/pads of Q2. I scrutinized it under a 10x loupe but couldn't see a solder bridge. Decided the bridge must be under the device...desoldered and removed Q2, powered up the rig, and the welcome sound of "5W" came over the speaker. I still didn't see a short but I probably fixed it when I was removing Q2, because I put it back in, and now I am getting expected results. -Tim NC0Q