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Fun and games with the NC-183D




 
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Author Topic: Fun and games with the NC-183D  (Read 672 times)
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KB2WIG
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« on: November 25, 2017, 11:21:15 AM »

I recently picked up a National 184d that had been sitting in an attic since the early '90s. I used my incandescent variac and fired her up. Very little noise from the speaker, but the installed dual electrolytic seemed to be OK. So I started to replace parts, particularly wax paper caps as a online search returned tales of woe.

As of Wed night, most of the paper caps and almost all of the electrolytics were replaced. The static levels came up to a nice level, but no signals......  So, I grabbed my trusty GDO, and went searching for  its signal on 75m. MY scope knob(s) broke, and then the fun began. While moving the GDO dial around, I was able to 'find' the signal. So things are looking goodish, but with my 80m dipole connected, nothing off the air. Then .......   rocking GDO knob, out pops some CW. Tuning the GDO tunes the receiver !             Amazing!

 D'oh ! !  I've just replaced the LO.  With out the GDO, nothing.

I'm waiting for a tube shipment to shotgun the radio. I bought a  tube for the Converter and one tube for the IF locally, and continue to play around with this beast. ( Yeah, I can buy tubes from a real lectronics store ! Stewart W. Smith, here in Syracuse) Today, more parts to stuff inside.

If it snot one thing its another.

klc
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K4CCW
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« Reply #1 on: November 25, 2017, 11:32:04 AM »

Restoring these oldies is always a fun education or, sometimes for me, a re-education. Cheesy

The 183-D is still on my wish list, mainly 'cause it's such a good looker.

I'll be following your adventures with interest.
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KA2DZT
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« Reply #2 on: November 25, 2017, 12:28:06 PM »

Check all the screen resistors throughout the RF and IF stages.  The 6BE6s converter tubes can be a problem.
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WD8BIL
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« Reply #3 on: November 25, 2017, 01:01:24 PM »

Quote
Check all the screen resistors throughout the RF and IF stages.  The 6BE6s converter tubes can be a problem.
Yup...... what he said.
My R390A had a very low sensitivity problem when I got it. Turned out to be open screen resistors in IF amps 2 and 3!

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KB2WIG
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« Reply #4 on: November 25, 2017, 01:33:54 PM »



well, I'll not have to go boldly as someone else replaced the 47K screen resistors. These are a "known" problem area...... I've got 3 more 'problem' caps to replace.

This thing is complicated, so I am trying to get it going on the single conversion side. I wish I had got 2 of the 6be6 tubes,  the 183d is a dual conversion; so I don't have to trace out which Converter is only used for the 455 IF..... 

And its 1:30 PM, my 160m el is somewhat strung - I'm threading it between the trees and scrub.  SO its outside in the next few minutes and get the arrow out of the sky.

thanks,

klc
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WD4DMZ
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« Reply #5 on: November 25, 2017, 02:34:04 PM »

The NC183D is one of the last receivers on my wish list. Next Frostfest in Richmond might bring me some luck. I will be watching your progress to find out where the big issues might lie should I acquire one.

The toughest receiver I have dealt with was a Hallicrafters SX42. What a chore as some paper caps in the RF amp sections are just not accessible. Once working it took a prominent place in my boat anchor station as it sounds great.

I learned what tubes need to be on hand for these kind of projects so am now rarely caught empty handed. However, every so often I need an odd one so I usually buy 2 of each when ordering tubes.

Keep posting.

Rich
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Jim, W5JO
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« Reply #6 on: November 25, 2017, 03:35:58 PM »

I think you may find that the majority of resistors in the set have wandered off the reservation and  should be replaced.  Be sure to clean that switch that changes the conversion scheme well along with all the oscillator and mixer stage switch wafers.  If the IF transformers do not peak properly then you may have to go inside of the cans and replace the little mica caps.  I have seen several sets that required replacement in one or two of the transformers. 

If it has been in an attic and subjected to temperature changes then  switch contacts are probably covered with a difficult to remove film that prevents them from making good contact.  I suggest you not use Deoxit on them, I saw a 183D that someone used it and the stuff helped continuity between contacts.  Then after a good cleaning of the switch it came back to life.

Actually it is a very straightforward receiver and a very hot one once it is playing correctly. 
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KB2WIG
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« Reply #7 on: November 25, 2017, 05:19:50 PM »

Rich, good points r/e the tubes. MY policy is to always have a replacement... or 5.   I was hoping the tubes would be OK. They all may be, but I ordered a replacement set anyway.  Like having 2 scopes in case one craps out.  Well  my Tek RM45 and 453 are kaput. the backup for  the '45  was the 453, which craped out yesterday ( I'm using a vise-grip to turn the TIME/ switch, so it works). Too lazy to fix things up, so now I suffer.

Jim, yes the switch contacts all seemed to be oil coated. I used C3H8O to clean things up a bit.  The ganged slide switch was very dirty, and still needs some work.My can of DeOxIt is at least 14+ years old. I use it, with tooth picks or Q-tips, very little. It's got Heptane, and we all know about that.

I'll keep all posted.

klc

P.S. I got the arrow back, and replaced the fishing line with #14 AWG THHN. 2?3  of the way there, so I'll pollute 160m this winter.
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MikeKE0ZUinkcmo
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« Reply #8 on: November 25, 2017, 05:48:30 PM »

The 183 is one of the prettiest radios ever, I think.   I had one several years ago and sold it for some reason, so I had to buy another here a year or so ago.



They're easy to work on, and the size of capacitors today make replacing the oldies a snap.   I used a piece of Vector board to mount the replacement PS caps on.  

Just remember, the positive end of C-65 goes to ground, and negative goes to B-, along with the negative of both sections of C-64.   None of those two cap's negatives go to ground.
  
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KB2WIG
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« Reply #9 on: November 25, 2017, 06:58:24 PM »



M, have no fear, the caps are safely " above gnd ".


KLC


More to follow.
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K4CCW
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« Reply #10 on: November 25, 2017, 09:15:16 PM »

The 183 is one of the prettiest radio ever, I think.

Indeed! And yours is a great specimen, Mike.

Quote
They're easy to work on, and the size of capacitors today make replacing the oldies a snap.   I used a piece of Vector board to mount the replacement PS caps on.  

I like that method, Mike. I hope it's not patented. Cheesy
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MikeKE0ZUinkcmo
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« Reply #11 on: November 26, 2017, 08:23:31 AM »



Quote
I like that method, Mike. I hope it's not patented. Cheesy
If it is, I guess we'll both be getting a letter!!
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WA4WAX
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« Reply #12 on: November 26, 2017, 04:55:09 PM »

Terry of D-Labs is a good resource.  Here is one of several videos on the 183D.

Matt

https://www.youtube.com/watch?v=JJMhDsX7ixM
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WA2SQQ
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« Reply #13 on: November 27, 2017, 09:08:01 AM »

About 45 years ago I had a one of these. I did a real stupid thing - I repainted the case to a wrinkle finish black. Beautiful job, buy looking back I can now appreciate what the original paint is worth. I often wondered what ever happened to it. It would be a real easy one to spot!
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W7NGA
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« Reply #14 on: November 27, 2017, 09:28:56 AM »

The NC-183 restoration was fun. Same with the HRO-50T1 until I found the big slab of asbestos shielding the power supply!

W7NGA dan
Seaside, Oregon


* nc.jpg (292.74 KB, 720x524 - viewed 44 times.)
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WA4WAX
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« Reply #15 on: November 27, 2017, 12:01:45 PM »

Another D Lab video.

https://www.youtube.com/watch?v=EatZT8shpJA
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MikeKE0ZUinkcmo
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« Reply #16 on: November 29, 2017, 06:28:48 AM »

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...same with the HRO-50T1 until I found the big slab of asbestos shielding the power supply!
So long as you don't mess with it it's fine. 

Its when you start messing with it, trying to remove it, or otherwise creating dust, and inhaling the stuff, that you start putting yourself in danger.  As the saying goes, "leave sleeping dog lay".   

If you feel you MUST to do SOMETHING, brush, don't spray, a liberal coat of clear polyurethane on it, being sure to cover the edges.
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KB2WIG
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« Reply #17 on: November 29, 2017, 10:23:46 AM »


Well, after replacing almost all the no mica caps, and nothing inside the IF cans, I exhibited due diligence and recorded voltages.  all the 6v filament voltages were 6.35 volts, so that's not much of a problem. The most disturbing results are in the IF stages. The first grid of  the 6BA6 IF's are supposed to be 2.3 V; I'm getting  - 3.14 V.   It looks like I'm going to have to go in the IF cans themselves and see if something is amiss.

( the anode(s) of the 2nd detector are both off...  pin1 1.4 V is 3.23 V, pin7 -2.6V is -4.07 V).

New tubes arrive today.

klc
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