Warning: Creating default object from empty value in /homepages/11/d132647312/htdocs/Amfone/mkportal/include/SMF/smf_out.php on line 47
A question about the National 2-40D




 
The AM Forum
September 20, 2018, 01:22:53 PM *
Welcome, Guest. Please login or register.

Login with username, password and session length
 
   Home   Help Calendar Links Staff List Gallery Login Register  
Pages: [1]   Go Down
  Print  
Author Topic: A question about the National 2-40D  (Read 715 times)
0 Members and 1 Guest are viewing this topic.
KG0MN
Member

Offline Offline

Posts: 55


« on: August 22, 2018, 05:05:31 PM »

I have all the caps to replace them in my National NC-2-40D receiver and I am hoping someone can tell me how to go about removing the catacomb carriage located on the bottom of the unit. It seems I read somewhere that a spreader was needed to remove this unit, can anyone verify this or offer suggestion to me to make this job easier?

Thanks and keep on radioing
Kevin -KG0MN
Logged
w3jn
Johnny Novice
Administrator
Member

Offline Offline

Posts: 4572



« Reply #1 on: August 22, 2018, 06:32:34 PM »

You don't need to remove the catacomb.  Just crank it over to one side, do the caps showing, then crank it over to the other side and do the rest.

Unless you know for certain there are bad caps inside the catacomb, I'd definitely leave it alone.
Logged

FCC:  "The record is devoid of a demonstrated nexus between Morse code proficiency and on-the-air conduct."
Carl WA1KPD
Contributing
Member
*
Offline Offline

Posts: 1478



WWW
« Reply #2 on: August 22, 2018, 11:36:47 PM »

Also make sure the new caps lie close to the chassie, so when the catacombs slides back and forth they don't rub.
Great radio
 
Logged

"Okay, gang are you ready to play radio? Are you ready to shuffle off the mortal coil of mediocrity? I am if you are." Shepherd
MikeKE0ZUinkcmo
Member

Offline Offline

Posts: 298



« Reply #3 on: August 23, 2018, 06:50:42 AM »

Although it is quite true you don't need to remove the catacomb, it does make working on the radio LOTS easier.    The process is quite simple.  

Each of the bands have 3 modules that connect to the radio via the connector under the casting.   Simply remove one of the "center" bands modules, move the catacomb so the "empty band" is over the connector fingers, and take it out.



The Catacomb is held in place at the rear of the chassis by the rod going from side to side.  The rod is mounted with a single screw in each end, and a center bracket.   FIRST and very IMPORTANT, pull the band change/tuning knob to the "OUT" position.

Remove the rod end mounting screws and the two screws holding the center bracket, hook your index finger under each end of the rod.   Smartly lift one end, then the other.  The ends will snap over the dimples in the chassis.   The rear of the catacomb can now be lifted and pulled toward the rear of the chassis and easily removed.
 
I covered the 240D fairly well during my rebuild SO TAKE A LOOK (click on) all the titled pics

The BIG connector is undoubtedly pretty dirty so now is a great time to use some good cleaner, and cotton swabs, and clean the fingers well.  



They may also be somewhat splayed so some adjustment might be in order.  Don't forget the pins on the modules, I did some gentle burnishing of the pins with some fine steel wool.  Then some contact cleaner SPARINGLY applied with a Q-tip  or cotton swab, to each of the pins before re-installing the catacomb.


Logged

Mike KE0ZU

Bold Text and PICS are usually links

https://mikeharrison.smugmug.com/
KG0MN
Member

Offline Offline

Posts: 55


« Reply #4 on: August 23, 2018, 08:43:33 AM »

Mike thank you so much for the information and pictures of your experience with the 2-40D. These will be the perfect aid to help me with this project. I think the radio has two major issued beside the need to be recapped. I know the main tuning knob is in need of a good cleaning as well as the fingers. It seems when the tuning knob places the catacomb in the resting place for a certain band the noise is really muted until you turn the knob a  bit past the center detente in either direction. This leads me to believe that as the pen slides in between the finger that is cleans the outer parts of the fingers as it enters them. That might explain why if the tuning knob is rocked a little past center in either direction I can obtain a signal.
Logged
N3GTE
Member

Offline Offline

Posts: 74


« Reply #5 on: August 23, 2018, 04:21:20 PM »

+1 Mike
Have done a couple, a NC-200 and a NC-100X both were very dirty and one had a broken contacts. Well worth the effort to get it all cleaned up and making good reliable connections.
Would hurt to checkout the bushing have had one of them get loose. It's pressed into the catacomb. Think I need to peen it or something. Makes the bandswitch bind.

Terry
Logged
MikeKE0ZUinkcmo
Member

Offline Offline

Posts: 298



« Reply #6 on: August 23, 2018, 11:30:35 PM »

Having to rock the casting past the detent is THE indication that the switch/pins are dirty.   Once clean you won't have any of that.   You'll find out just how dirty when it comes time to clean them.   That process will most likely take better than an hour.

In the pic you see most of the sets of fingers are "closed" but others are "open" or somewhat spaced apart.    Those open sets have to  be adjusted so they are closed.   Cleaning you'll need to get Q-tips or cotton swabs down into the area where the pin sets when making contact.  


Incidently I happened to find a pic which shows how the catacomb "empty band" should be aligned with the contacts in the receiver when installing or removing the catacomb.



Not too clear, but you get the idea.

I'll also upload some pics of the mechanical "cable routing" for the "band" indicator.
Logged

Mike KE0ZU

Bold Text and PICS are usually links

https://mikeharrison.smugmug.com/
Joe Connor
Member

Offline Offline

Posts: 33


« Reply #7 on: August 24, 2018, 04:45:29 PM »

Just a couple of things:

1. I did mine without removing the catacomb, and it can be done. Whether you do it that way or Mike's way, however, the key is to thoroughly clean the pins and fingers. It improves performance considerably. No more wiggling the bandswitch knob to get a band to engage.

2. When adjusting the open fingers, as Mike suggests, make sure they still line up straight after the adjustment. When changing bands, the catacomb and fingers come through with significant force and you don't want to mangle any of the fingers.

3. On Mike's pictures, note the small caps he used. That's a great idea because the catacomb has to slide above the caps. You'll also note that (in addition to the very neat workmanship), Mike replaced some resistors. In these sets, a fair number of the resistors seem to drift high.

4. These are tremendous receivers and well worth the time and effort to do things right.
Logged
KG0MN
Member

Offline Offline

Posts: 55


« Reply #8 on: August 25, 2018, 12:05:06 PM »

how are the fingers adjusted if they have a large gap?
Logged
MikeKE0ZUinkcmo
Member

Offline Offline

Posts: 298



« Reply #9 on: August 27, 2018, 08:22:34 AM »

The fingers fit somewhat loosely in the block, and I pushed an Exacto blade between the two contacts pressing down into the block, to hold things steady there, and then alternately pressed the two contacts against one another.

Logged

Mike KE0ZU

Bold Text and PICS are usually links

https://mikeharrison.smugmug.com/
KG0MN
Member

Offline Offline

Posts: 55


« Reply #10 on: August 27, 2018, 09:28:01 AM »

Thanks again Mike that make sense and I should be able to follow this example.

73 - Kevin KG0MN
Logged
Pages: [1]   Go Up
  Print  
 
Jump to:  

AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
 AMfone 2001-2015
Powered by SMF 1.1.21 | SMF © 2015, Simple Machines
Page created in 0.053 seconds with 18 queries.