[Hallicrafters] R-274 Resto Update

[Thomas Hoyer]

It's been a few weeks since I've updated where I am on this project. Last time I posted that I found all of the input antenna coils had fused wires. I was able to procure some replacements and rewound one of them. 


Got to apply power this weekend, started with no tubes installed just to check the power xfmr outputs. When I applied power through a variac - I measured nothing on the secondaries, GREAT......... After some head scratching I found that SOMEONE had forgot to install the fuse. Put a new fuse in and all of the xfmr voltages looked good. Installed the rectifier - got good DC readings. Installed the rest of the tubes and all of the voltages look good.


Started walking a signal through the different stages. The 455 signal path is good and I was able to calibrate that section. The 6mc sections also checked good. Putting a real signal into the RF path all bands work EXCEPT band 1. Moving through the RF sections The first section that does not work on band 1 is the mixer section. I suspect something in T19 or possibly T13 but they both look good visually. The coil in T19 does not measure per the book though for one of the windings. I'm measuring in the 10's of ohms vs single ohms as specified. Possibly one of the windings is damaged...........?


Progress


Tom
W3TA