As Jim says, you may be losing drive to the final grid because the drive signal is going away. But that's not all that can go wrong. Make sure the final grid bias resistor hasn't drifted off-tolerance or changing value as it heats up. If it is, replace it. I have also had bad final tubes (pair of 6146s in a DX-100) create the symptoms you describe. Originally I thought for sure the problem was with the drive signal, but that wasn't what it turned out to be.
73 es GL, -Larry/NE1S > Brian the final is losing drive from the driver/buffer/VFO. Check all > tubes first then if that doesn't fix it you will be troubleshooting > under the chassis to find out what components may be changing value. > > Jim/W5JO > >> My Heathkit DX-60 grid current drops after a couple of minutes and >> will keep dropping more rapidly as I increase drive level. Eventually >> the tube plates glow red. I am tuning by the book. >> Any ideas? >> >> 73 >> Brian > -- Pay a visit to my amateur radio web page at: ne1s.rfburn.org ______________________________________________________________ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/[email protected]/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: [email protected] To unsubscribe, send an email to [email protected] with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
