[Boatanchors] National NC-101X Adventure and Questions

[Oliver J. Dragon]

Great story Scott. Felt like I was right there at the bench with you as you 
went through the restoration. Appreciate your writing up the experience!

73
Ollie





At 12:07 PM 03/06/2006, Freeberg, Scott (STP) wrote:
>I just bought a gorgous NC-101X from Don Merz and it arrived Thursday, 
>just in time for a weekend NC-101 adventure :)   Unfortunately I was down 
>with the flu and didn't even know it arrived.  Saturday I felt pretty 
>good, the girls went shopping, I was still recovering so there was no 
>'honey do list', which meant RADIO DAY :->>>> Spent the whole day with the 
>101X.  Also spent a few hours on Sunday as well.  So I thought I'd share 
>my 101X restoration adventure with you, plus ask a few questions.
>
>Opened the lid and saw the chassis and parts were really really nice, 
>surprising nice for a 67 year old radio. I did go in there with the brush 
>and vaccum, and cleaned out the dust and cobwebs.  I pulled the tubes, 
>cleaned the grime off, put a dab of DeOxit on each pin, put em back in.  I 
>should have tested the tubes at this point but for some reason decided not 
>too.  I pulled off the bottom and looked around.  Nice, dusty, cobwebs, 
>few bugs, so went in there with a brush and vacuumed it out as well.
>
>The moveable catacomb coil box is a sight to behold.  That must have cost 
>a fortune to make.  Anyway, it barely turned, no doubt due to the old and 
>stiff grease on the gears, and no grease on the sliding bar.  I cleaned 
>off the old grease, put new grease on, lubed the shaft bushing, greased 
>the sliding bar, wow, turns pretty good now.
>
>The PW dial turned roughtly with a kink every revolution. I removed the 
>dial and started cleaning the system. I lubed up the variable capacitor as 
>necessary and put DeOxit on the 6 or 8 rotor contact points.  I didn't 
>notice much improvment in tuning.  I opened the PW drive box.  I've never 
>seen one before so it was fun finally seeing one. Yuck, old sludgy 
>grease..  I'll bet I spent 45 minutes working in that little PW drive box 
>with a stiff short bristle brush and WD-40, getting that old stuff off the 
>gears.  Then I put new grease on and closed it up.  I then turned the 
>radio so the front panel shaft bushing was facing up, oiled it, and let it 
>soak in for a while.
>
>The PW dial was a NOS black dial.  Don told me the new dial had been 
>installed because the original had plating missing, and luckily for me, he 
>included the original silver dial in an envelope.  I'm more of an original 
>kind of guy, so I looked over that original silver dial, and I thought it 
>looked great.  Yes the plating was worn in that area just beyond the knob, 
>for about an inch, but the radio was calling out for the original 
>knob.  So I cleaned the old stiff grease out of the silver PW dial, raided 
>the new PW dial for the springs, the put the silver dial back 
>together.  At first I looked at the two dial pieces, the knob, and 
>springs, and wondered where in the heck the springs went.... Thanks to the 
>generousity of another ham who scanned the PW dial instructions and put 
>them up on BAMA, I was able to see how it went together.
>
>I plopped the PW dial back on the shaft and gave her a spin.  Oh my!  I 
>was shocked at how smooth the tuning was, and no kink either.  It's like I 
>spread 'buttah' on the mechanism :)
>
>The LV fuse was missing.  This was not a good sign.   I wondered if it was 
>missing because of some serious problem...  I didn't have any documention 
>that mentioned fuse values so I plopped in a 4 amp fuse.  I need to find 
>out what the right value is supposed to be.
>
>In spite of my better judgement, I powered up the radio before just flat 
>out replacing the hv caps.  I measured 276 vac at the hv 
>filter.  Oops.  The value of good judgement was confirmed, though not 
>followed...  I didn't want to mess with removing chassis mounted cans so I 
>just clipped the wires, left the cans in place, installed some new 
>electrolytics under the chassis.  I found some excellant mounting spots 
>and put the caps in.  Only when I was all done did I make the discovery of 
>why there were no tall parts under the chassis.  I looked at that moveable 
>coil box, then looked at my caps, and realized there was an unanticipated 
>problem :)  I moved the coil box over the caps and noted them making 
>contact...   I made a few changes and have all three electrolytics 
>flattened against the chassis.  This time I measured less than 1/2 volt AC 
>at the filter.
>
>I found the last electrolytic sitting in the upper left corner, hidden by 
>the coil box.  It was a big metal cylinder cap, 10 mfd at 50 volts.  It 
>was riveted to the chassis, so I just removed the connection and soldered 
>in a 10 mfd 160 v cap.  I note that the new cap is maybe 1/30th the volume 
>of the old cap.
>
>I powered up the 101X and soon heard cw, sans BFO though.  About two 
>minutes later the BFO showed up and I listened to beautiful cw around the 
>bands.  SSB sounded good too.  Later the bfo disappeared. I tested the BFO 
>tube, and feeling stupid about not testing all the tubes before, tested 
>the rest.  All tubes were good.  So I checked the BFO switch, hoping maybe 
>the oscillator wasn't turning on.  Bingo.  The switch was infinite 
>resistance in both positions.  I removed the switch, held it facing up, 
>sprayed DeOxit around the ball, and worked the mechanism.  This this it 
>yielded 0 ohms, but in both positions.  Oops, too much.. I shook out the 
>DeOxit, still 0 ohms.  So I ended up blowing on the switch like a straw, 
>flushing out excess DeOxit.  Then it worked fine.  Its not like any switch 
>will work in that position.  The shaft is straight, short, and 
>notched.  Turned the 101X back on, and the BFO worked FB.
>
>The signals sounded beautiful from that huge speaker cone and pair of 
>6V6's in P-P.  The cw signal would drift though, noticeably.  I tried to 
>back off the RF gain, like I do with the 75A-1 where I run AF max and 
>lower RF.  At '10', I had full gain, but by 8.5 I had 0 gain.  I removed 
>the pot and found that it had a removable cover.  Popped the cover and saw 
>the guts.  The wirewound wire only ran about 1/2 around the pot, plus at 
>that 8.5 spot the resistance changed abruptly.  I cleaned the elements but 
>got the same results.  So I'll have to replace the pot.  I don't know the 
>value of it yet.  It's a 0.25" diameter round shaft, with a 0.5" shaft 
>length, and 0.5" thread length.
>
>The 6E5 green tuning eye didn't work.  I did check the connector and it 
>seemed to have the proper voltages.  I checked the 6E5 on the TV-7 and it 
>didn't respond at all to the open test and closed test, so I'll have to 
>look around for one of those.  Anyone have a 6E5?
>
>I spent some time Sunday afternoon tuning around 20 meter and 40 meter cw 
>and ssb.  Wow, this 101X is an incredible receiver.  Besides looking like 
>a million bucks, it has beautiful sounding signals, incredibly smooth 
>tuning, I love it!  Once I finish the restoration of the 101X, then I can 
>finish building the power supply for my 1935 Gross CW-25 
>transmitter.  Then I"ll be putting this pair on the air for some fun 
>1930's operation!
>
>So that was my 101X adventure so far.  It was a fun day and interestingly 
>enough, the 101X wanted to be restored and put on the air.
>73, Scott WA9WFA
>
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