I have tried tuning her up only to find a disconnected coax ( 2 rigs no switch ). But when it's connected... it goes into a 300w dummy load. I do have to tune the antenna on air though. I noticed on your great CD, while looking for a titanium cap, that the relay there is wrapped in what looks like asbestos. I'm not certain mine is there... should it be???
All three PA tube are Sylvania. I run Times LMR400 UF... it's new but my old MFJ might be causing me problems. I bought it used over ten years ago. It seems to be ok with 100w but maybe the Drake stresses it out. That is on my have to replace next list. I'm not even going to try it with the drake again. Thanks everyone for the great ideas. When this get this sussed out you'll be the first to know. Rick Palmer Sorry for the dupe Garry On Fri, Aug 20, 2010 at 10:34 PM, Garey Barrell <[email protected]>wrote: > Richard - > > The fact that it didn't tune indicates that perhaps the antenna was either > not connected (relay?) or wrong band? or bad coax, or ... Possibly arcing > in the relay contacts or coil. > > What is the BIAS current? It should be 100 mA, if it's now 65 mA or so you > may have lost a final tube. > > Really not much to flame in the PA cage. You could get corona on variable > cap plates, again due to mismatch, but that is typically an ozone smell. A > parasitic could have fried one of the parasitic suppressors on the PA plate > caps. Are all three PA tubes from the same manufacturer? > > 73, Garey - K4OAH > Glen Allen, VA > > Drake 2-B, 4-B, C-Line& TR-4/C Service Supplement CDs > <www.k4oah.com> > > > > Richard Palmer wrote: > >> My TR-4 did not want to tune... it caught on fire that looked like it was >> at the PA section probably around the relay. All I could really do was grab >> switches and plugs faster than anything I've done in the last twenty years. >> >> The smoke was not the conventional electric smell. It was very acid and >> burning. I sorta took in a nose full doing the above and felt high, in a bad >> way. I just got around to looking at it and can not find any burnt or >> distorted part. There is absolutely no sign of soot or heat anywhere. Seeing >> this I tried to tune her up again. I was getting a very solid 4.5 for the >> plate current. Now it's only 3. Is it possible (likely) that I "smoked" one >> of my PA tubes? >> >> Thanks in advance, >> Richard Palmer >> KB8NXO >> >> > _______________________________________________ > Drakelist mailing list > [email protected] > http://mailman.zerobeat.net/mailman/listinfo/drakelist > >
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