National RAO version

[Avery W3AVE]

I pulled up the NC-100/101 thread from last year (http://amfone.net/Amforum/index.php?topic=5731.0) to see what I could figure out about the radio I picked up last night. There are four small holes at the top left of the front panel where I bet the ID plate used to be.

From the conformal coating and shock mounts, it would seem to be an RAO. My first question is how to tell which version. Someone in the thread said he had one of the later versions--one-piece cabinet, no S-meter. That matches mine. What other clues to the specific version should I look for--assuming I'm correct in thinking it's an RAO--and are there individual manuals for the different versions, or was there one manual that was updated with each new version?

There's a six-pin Cinch-Jones female connector on the front at the upper right. Looks like a factory job and the wires seem to be the same vintage as the rest. What's it for?

Finally, the power xfmr cover is missing and I'd like to replace it even though it's probably totally unnecessary performance-wise. If any of the 100/101/RAO veterans who posted to that thread have one, I'd be happy to pay.

Mostly I lurk, but I do appreciate the collective experience and wisdom (they're not necessarily the same thing, are they?) I've found here.

Avery W3AVE
Potomac, Md.

[Tom WA3KLR]

There was another topic recently also on NC-100 variants:

http://amfone.net/Amforum/index.php?topic=8409.0

I still have not been able to identify my receiver after collecting other Rxx schematics.

The next thing to do is take digital photographs of the front panel and the top of the chassis of your unit and post them here.  Also state what the tube complement is and the i.f. frequency if known for sure.  When you post, select "Additional Options" and then at "Attach", hit "Browse..." and select the picture file (jpg, gif, mpg,) right from your hard drive.  For a second and third photo in the same posting, select "(more attachments)" and continue to specify up to 2 more photo files from your hard drive, maximum photo size 600kb.

Then we maybe able to help you more.

[Avery W3AVE]

Will do, once I lug the thing downstairs and get it out of the case. Thanks for the additional thread.

Avery W3AVE

[Avery W3AVE]

Tube complement:
4-6K7
2-6J7
1-6C8
1-6K6
1-5Z3

I shot 10 pix, but apparently the files are too large. I can email them to anyone who'd like to see them.

Thanks for any help you can offer!

Avery W3AVE

[Tom WA3KLR]

Avery, thanks for sending me the photos.  It looks to me that you probably have a RAO-7 or -9.

There is a nice web page with identification information for the RAO series at:

http://oak.cats.ohiou.edu/~postr/bapix/NC120RAO.htm

Also, there is a 20 page RAO-2 manual on the BAMA site at:

http://bama.edebris.com/manuals/national/rao2/

You'll need to have the IrfanView program to view and print the pages from the downloaded manual file.

The RAO-2 manual lists the tube complement including a 6F8 and a 6J5 besides the tubes you mentioned previously.

[Avery W3AVE]

Avery, thanks for sending me the photos.  It looks to me that you probably have a RAO-7 or -9.

There is a nice web page with identification information for the RAO series at:

http://oak.cats.ohiou.edu/~postr/bapix/NC120RAO.htm

Tom,

From the description on this web page of the various versions, I have an RAO-7. Mine has no lid, which the RAO-9 does. Another 6K7 also needs to be added to the lineup I posted--a 2nd RF stage used as a preselector/isolating stage to minimize radiation. It also looks from the numbers on the IFs and other chassis-top parts that this radio was built by National as opposed to Well-Gardner.

Any idea of the function of the C-J connector on the front panel?

Seeking power transformer top cover and manual. Was there a TM-xxx for this model?

Thanks for the detective work, Tom.

Avery W3AVE
Potomac, Md.

[Tom WA3KLR]

Avery,

From your photo only two pins are being used on the 6-pin Jones.  Looks like the wires are connected to the pilot lamp wires - 6 V.a.c.

With the exposed power transformer being painted gray, I wonder if it is supposed to be that way.

[Avery W3AVE]

Avery,

From your photo only two pins are being used on the 6-pin Jones.  Looks like the wires are connected to the pilot lamp wires - 6 V.a.c.

With the exposed power transformer being painted gray, I wonder if it is supposed to be that way.

Why would they bring 6.3VAC out to the front panel??

On the transformer, you very well might be right, but it's got the two holes for the cover.