Spec sheet 9/56
Sales letter - 9/56
Tag on AFG control
More photos of NC-300, NC-303, and speakers coming soon.
Send comments and corrections to nick@virhistory.com
download pdf file - thanks to Bill W0NG
The introduction of the NC-300 was preceded by a highly publicized contest to design the "Dream Receiver" (photos coming soon). The early ads showed a different S-meter arrangement than the production units.
Spec sheet 9/56 |
Sales letter - 9/56 |
Tag on AFG control |
The serial number is stamped into the top of the chassis just behind the crystal calibrator socket - just lift the lid and take a peek. Please send me e-mail with info on your NC-300 - thanks to all the contributors so far.
It appears that some early NC-300's had a gray smooth glossy finish on the bezel and/or cabinet - later units had a gray wrinkle finish. Interestingly, it appears the last units made also had a smooth bezel but wrinkle cabinet.
Starting with the 2nd run (460-xxxx) a 20m band
mixer image trap made up of C86 and L18 was added. The last run (481-xxxx) had a 330 ohm resistor
substituted for the filter choke (L17).
| Serial No | Bezel | Cabinet | Filter Choke? |
| 434-0190 | smooth | smooth | yes |
| 434-0373 | smooth | ? | yes |
| 434-0694 | wrinkle | smooth | yes |
| 434-0752 | wrinkle | smooth | yes |
| 434-0827 | smooth | smooth | yes |
| 434-1227 | wrinkle | wrinkle | yes |
| 434-1481 | wrinkle | wrinkle | yes |
| 434-1789 | smooth | smooth | yes |
| 434-1791 | wrinkle | ? | ? |
| 434-1898 | wrinkle | smooth | yes |
| 434-1964 | wrinkle | smooth | no (???) |
| 460-0347 | wrinkle | smooth | ? |
| 460-0518 | wrinkle | smooth | yes |
| 460-0724 | wrinkle | smooth | yes |
| 460-1032 | wrinkle | smooth | yes |
| 460-1089 | wrinkle | smooth | yes |
| 460-1514 | wrinkle | ? | yes |
| 460-1588 | wrinkle | smooth | yes |
| 460-1840 | wrinkle | smooth | yes |
| 460-1852 | wrinkle | smooth | yes |
| 460-1865 | smooth | smooth | yes |
| 460-1888 | wrinkle | smooth | yes |
| 481-0050 | wrinkle | wrinkle | no |
| 481-0205 | wrinkle | ? | no |
| 481-0511 | wrinkle | wrinkle | no |
| 481-0952 | wrinkle | wrinkle | no |
| 481-0998 | wrinkle | wrinkle | no |
| 481-1011 | wrinkle | wrinkle | no |
| 481-1148 | wrinkle | wrinkle | no |
| 481-1176 | wrinkle | wrinkle | no |
| 481-1369 | smooth | ? | no |
| 481-1737 | smooth | wrinkle | no |
Choke/Resistor Variants -to tell them apart, lift up the top lid and look at the screw heads just to the left of the power xfmr - no need to look under the chassis.
 Early units - Two phillips head screws holding L17 choke in place |
 L17 choke under chassis |
 Later units - Two holes + two rivets holding terminal strips for 330 ohm resistor |
 L17 replacement - 330 ohm resistor under chassis |
I have seen 3 different instruction books so far - They match production runs. Please send me e-mail with info on any others.
| Publication (on last page) | Date | Features |
| SM-3000-ER434 | 8-55 | Does not say "IMPORTANT..." at top of first page Was 434-xxxx the first production run? |
| SM-3000-ER460 | 3-56 | "IMPORTANT... READ THE BOOK FIRST" AFG switch explanation is changed L86/C86 image trap added |
| SM-3000-ER481 | 9-56 | "IMPORTANT... READ THE BOOK FIRST" added R61 (100K ohms) added R62 (330 ohm replaces L17 filter choke) added R63 (2.2 ohm in series w/ 4H4-C ballast) added C87 (0.22 uf) Was 481-xxxx the last production run? |
 ER434 - August 1955 |
 ER460 - March 1956 |
NC-300 and NC-303 cabinet sides had light color above, dark below. Top was
light. Rear was light.
Note - Some close-ups were done by directly scanning the speakers and may have odd
reflections
Click on an image to get a 4X larger version
 Early model NC-300 (smooth finish bezel) another photo |
 Later model NC-300 (wrinkle finish bezel) |
 late model NC-300 with late model NC-300TS speaker (both wrinkle finish) |
 Early model NC-300TS (smooth finish paint) |
 Early model NC-300TS speaker grille - Ads also showed vertical striped grille cloth shown at left |
 Early model NC-300TS speaker
side view - smooth paint matches colors on early NC-300 front panel. |
 Late model NC-300TS speaker with wrinkle paint finish |
 late model NC-300TS speaker grille |
 Late model NC-300TS speaker
side view - wrinkled paint matches colors on later NC-300 front panel. |
 NTS-2 speaker that matches NC-303 and NC-400 Note chrome side strip. |
 NTS-2 speaker speaker grille |
NTS-2 speaker matches NC-303 cabinet - wrinkle paint - black portion matches
bezel color on front of NC-303. Light color is creamier than front panel gray. Has chrome side
strip |
 NTS-2 speaker variant - note different logo & location |
grille cloth appears to be the same | paint appears to be the same |
 NTS-1 speaker that matches NC-109 and NC-188. Note lower "two-tone" dividing line, different grille cloth, and no lightning bolt. - Wrinkle paint is close to late model NC-300TS but a little browner maybe. |
NTS-1 grille photo coming soon |
NTS-1 side photo coming soon |
| NC-300CC Converter Cabinet NC-303CC Converter Cabinet For mounting 3 VHF converters Both NC-300 and NC-303 paint schemes existed - NC-303CC had chrome side strips and darker gray. |
 Later model NC-300CC with wrinkle paint |
Here are some links to more info on the National NC-300 and NC-303
Please send send me e-mail with more
links or info on the NC-300 and NC-303 receivers
Thanks - Nick England K4NYW - Chapel Hill, NC
