Any NC300 Specialists out there?

[N8UH]

Hey guys!

I'm in the process of getting my newly acquired NC300 into top running condition. I went through it this week and re-capped it. I also re-wired the audio section to mimic the audio section of an NC303. So far so good. Just some hum problems to track down.

The big issue is the dial calibration. The indicator is around 40Kc down from the actual frequency on every band. Looking further into this, I notice that the main tuning capacitor is not fully meshed at the band edge, so there is an alignment problem between the capacitor and dial mechanism. The question is, can I re-calibrate the dial without ripping off the front panel? Perhaps some way to disengage the capacitor to reset it?

I'll take the front panel off if I have to, but... it looks like an ugly job... 

Thanks!

[Todd, KA1KAQ]

Carl KM1H or John W3JN would be the guys to ask. Both have a fair amount of experience with the 300. Never owned one myself, so can't help.

They'll probably wander by before too long.

[w3jn]

As I recall the dial pointer can slip on the dial cord - the cord is just looped around it.  Set the radio to a known frequency (electrically), then hold the tuning knob while you slide the dial pointer to the right spot on the dial.

I'm sure someone can correct me if my memory is incorrect.

[N8UH]

I tried doing that, but the pointer itself will not move on the cord, and even if it could, it would hit the crimped sleeve... 

I was able to slip the dial a bit, but only as far as the CAL SET knob would let me.

Any other thoughts?

[WQ9E]

On mine, with the cal set control centered, the capacitor is at half mesh with the dial set at 14.200 

How close to full mesh is your tuning cap when set to the low frequency stop? 

I wonder if you need to loosen and reset the large pulley on the front of the tuning cap?

[N8UH]

When set to the low band stop, the tuning cap is about 1/4" from being fully meshed. With the CAL SET centered, and the crystal calibrator on, the markers are reading about 38KC low.

How does one loosen the large pulley to reset the cap?

[WQ9E]

Tim,

I don't have my 300 apart but there should be one or two set screws holding the pulley to the tuning capacitor shaft.  This is the typical way mounting works on other radios.  Hopefully you can access it without having to remove the dial drum.

[N8UH]

I think I may have found out what is going on... Looking at the dial stringing diagram in the manual, the pointer is supposed to be on the right side of the ferrule. Mine is on the left. I'll just have to see if I can pop the cord off the pointer and move the thing without pulling the front panel. I may be able to get by if I pull the drum out, but that could open a can of worms.

Thanks guys.