eHam Forums => Boat Anchors => Topic started by: KA3IWU on October 27, 2012, 03:11:34 PM

Title: NCX-5
Post by: KA3IWU on October 27, 2012, 03:11:34 PM
I am restoring an old NCX-5 mk ii and saw there have been some talk of those on here.  Does anyone know where I could find some replacement knobs for one?  The bandswitch knob is cracked (it is one of the pointer style).  I may be able to repair it.  The other knob it needs is probably made of "unobtanium" - the main tuning knob is the way most of these seem to get, the spinner portion is broken off and missing along with the spun aluminum center.  Could probably make a new aluminum center, but the cracked off portion of the knob would be hard to make look correct.  I think another problem with these knobs is I believe they were attached with lead melted into holes in them making them almost permanently attached to the shaft they are on, so might need replaced as an assembly if they can be found.

Might have to just find another style knob and see what can be done with it.


Title: RE: NCX-5
Post by: AC5UP on October 27, 2012, 03:40:05 PM
I just pulled up an image of an NCX-5 and there's nothing exotic on the front panel. Very common communication knob types and a web search on " radio knobs " should give you plenty to look at. As for the VFO spinner, I know the spinner is handy but on that radio I think it looks odd, like something N4NYY would do. I'd go with a plain knob with fluted edges for a good finger tip grip.

Just Sayin'.

If all else fails, you can buy 10 of these: (
For ten bucks here: (

Any decent surplus house should have something that will work for you. Avoid all-plastic knobs as they will crack. The items shown above have a metal insert with two set screws and should be at least as durable as the stock knobs.

BTW:  If you're really cool you'll relabel the audio volume control to read 1 through 11.       It could happen.

Title: RE: NCX-5
Post by: W9GB on October 27, 2012, 05:30:54 PM
Bob -

IF you are going to restore a National NCX-5 Mk II,
it is always best to talk to those that have previously traveled this road.

Randolph Best, W7CPA restoration

Dale Parfitt, W4OP restoration

You can also contact, Carl W Huether, KM1H who served as Service Manager at National in 1967.

Some National knob inserts (HRO-500) are very thin spun metal caps,
while other models (HRO-600) used 1/8" thick aluminum disks for knob inserts.

National, being a New England based firm, tended to use mfg. in that region.
For KNOBS, this meant Raytheon, acquired by EHC, was a logical supplier.
EHC Control Knobs
These knobs were used in Collins avionics and some military spec gear from 1960-1980

ON-LINE EHC catalog of Knobs

Electronic Hardware Corporation (EHC)
320 Broad Hollow Road
Farmingdale, NY 11735
Phone: 631-752-1950
FAX: 631-752-1971
Newark Electronics and Allied Electronics are 2 well stocked distributors.

Title: RE: NCX-5
Post by: KA3YAN on October 29, 2012, 12:22:23 PM

Did this happen in shipping???  Good grief!!!  I purposely had UPS professionally pack the radio to avoid damage.  I'm really sorry that it didn't come to you as I shipped it.  ???


Title: RE: NCX-5
Post by: KA3IWU on October 29, 2012, 04:50:05 PM
I think you mixed me up with someone else.  I purchased this one from eBay in california.  It was received in the condition of the photos, so no problems with that.  The suggestion about EHC knobs really helps.  Am waiting for a proper power supply for it to start getting into the function of it, and was starting finding the right knobs to make it look more presentable.  I think I found the right ones and ordered some, will see what they look like when they come in.  I used to use an old NCX-3 many years ago and thought I would pick up an NCX-5 and see if I could get it running again.

Thanks for the suggestions!  I may be asking for more suggestions once I get it powered up depending on what I run into.


Title: RE: NCX-5
Post by: W0EP on November 09, 2012, 12:52:53 PM
Bob, I would be interested to know if you find the knobs you need.  I also have an NCX-5 with a couple of broken knobs.


Title: RE: NCX-5
Post by: KA3IWU on November 09, 2012, 07:16:32 PM
The post about looking for EHC knobs helped.  Ebay or several vendors sell EHC knobs that are very close to the originals.  Of course the hard to find one is the main tuning knob which on the original was a spinner style that may have been a custom one for the radio.  Closest I could find for that was a EHC knob made for various Henry radios and military equipment, but it had a black plastic center instead of the aluminum of the NCX-5, so I just used a solid aluminum knob that I found cheap to start with, and will decide later how far to go with the restoration depending on how the electrical side of it goes...

Title: RE: NCX-5
Post by: KA3IWU on November 23, 2012, 11:34:09 AM
Not sure if I should start a new thread or continue this one - another question on restoration of this same radio.

I am making progress - power supply working, and receiver is coming to life on all bands.

Trying to go through the alignment process from the manual and found that a slug in one of the bandpass filter cans seems to be "frozen".  It is a dual slug can, and the top slug I was able to move, so it is not against the bottom slug top but the bottom slug will not turn in ether direction.

Any tricks or suggestions?  Anything that can be applied to loosen up the stuck slug?  I guess worst case is dismantle the can and drill out the slug and put in another similar sized slug from a donor can?

I hope to get this thing working and am happy with the results so far.  still need to work out an agc issue and an intermittent speaker wiring problem and then move to transmitter once everything else is fine.


Title: RE: NCX-5
Post by: W7APM on November 24, 2012, 11:31:44 PM
UPS professional packing is a joke. Kids and people who have no clue what mass times acceleration equate to...I wouldn't buy anything fragile packed by UPS "Professionals"

Title: RE: NCX-5
Post by: AC5UP on November 25, 2012, 06:35:27 AM
Anything that can be applied to loosen up the stuck slug?  I guess worst case is dismantle the can and drill out the slug and put in another similar sized slug from a donor can?

Drilling should be reserved as your last option... For all you know the slug is a special mix.

Unless you've changed condensers within that circuit are you sure it needs to be aligned? Does the other slug in the can give you a clean peak or null? If so, there might not be a compelling need to tweak that slug. OTOH, you'll never know if it's peaked until you give it a wiggle.

If you dismantle the can I can see two options before you drill it: Beeswax was often used to secure slugs against vibration and, even though the wax is old and dried out, a selective application of heat might loosen the bond. A mild solvent like WD-40 can also do the same but might take days to penetrate down to the last thread. WD-40 evaporates within a few hours so you'd need to check the slug once or twice a day then re-apply as needed if you go that route.

Spray it, wait, test, spry it, wait, test, until it starts to loosen.......... ( ? )

Title: RE: NCX-5
Post by: KA3IWU on November 25, 2012, 03:37:36 PM
Just wanted to give an update - I have the tx bandpass transformer working now.  Someone in the past had messed with this with the golden screwdriver, as the top core that was not stuck was wound almost the whole way out of the can.  The bottom one appeared to have been driven down to the bottom and jammed there and I believe split.  I removed and opened the can, was able to break apart the bottom slug and get all the pieces out with a dental pick and a carbide bur in a dremel.  I then sanded down a same sized donor core so that it would not be tight fitting and ran it up and down to make sure it would go smoothly.  Then reassembled the can, put it back in circuit with no leftover parts and with a little adjustment was able to finally get TX signal through the driver stage (the bandpass coil was so far out of alignment originally nothing was getting through to the driver).  Just a few more gremlins to go.