[ARC5] Dead BC-348-R

[J Mcvey]

 Is it the plate supply limiting resistor supplies B+ via the transformer winding?maybe there is something amiss inside the transformer.Did you also check resistance to ground at the transformer leg?

    On Tuesday, August 9, 2022 at 09:06:26 PM EDT, JAMES FALLS <radio-tuber at att.net> wrote:  
 
 My BC-348-R is dead after a year of quiet. The dyno sounds like I remember it, not lugging down. I started with capacitors. 

I was last inside it 10 years ago, got everything happy and aligned. I replaced a bunch of caps and resistors at that time. Now, all the remaining 0.1uF paper canned caps (48-2/3, 49-2/3/4) are very leaky. I will replace them as the others. 

This time, I found resistor 57-5 (4.7k) fried between the 1st IF (6K7) tube and the 2nd IF xfmr. So, from the schematic, it looked like B+ was being shunted thru mica capacitor 11-9 (.01) to ground. I lifted one end to test, and it’s OK. No leakage on my cap checker, infinite resistance on my VTVM. 

All tubes good to excellent. 

My question is what else would make this resistor burn up so all I can see is the first yellow stripe? 

I’m at a loss, so I’m asking the MilSurp Wizards for help on this. Any ideas?

Jim Falls K6FWT 
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