National NC-183D Help

[rich]

Hi
I just got a National NC-183D Receiver
It was sitting for a few years.
I turned it on and it seems the RF gain is low.
As you turn up the RF gain nothing is heard til you
get up to to the number 8 on dial.
So no receive until you turn dial up to 8 and I turn it up to 10,
I hear signals on AM SSB fine.   But need to get the RF gain higher
so signals come in stronger.
The glass tubes seem to be on.
Can it be the tubes or something else?
It seems to receive all bands but 40 Meters.
Thanks for reading
Rich  NJ

[Jim, W5JO]

It is a very quite receiver until an antenna is attached and the gain turned up.  Mine is similar in operation to what you describe.  If it has been sitting for several years, it may need several things, electrolytic caps in the power supply, the screen bypass caps can be leaking, and some resistors may be high in vlaue.

Give it a very good cleaning and check it thoroughly with a cap checker and ohm meter.  When you are sure the parts are correct, do a voltage check and proper alignment. 

[The Slab Bacon]

I also have one. and it is a very nice receiver with good sensitivity all the way up through 6 meters. You can read my report on it in my "Slab Bacon's Receiver Road Test" article found it the tech section here. I find it to work very nicely with no lack of sensitivity.

If you have sensitivity issues, you prolly have some other underlying issues. REPLACE ALL OF THE TUBULAR PAPER CAPS!! in the radio, check as many of the individual resistors for tolerence as you can get to. (I replaced 6 in mine) and lastly check the tubes and alignment. You will be rewarded with a wonderful receiver with lots of great audio.
                                                            The Slab Bacon

[rich]

I of course have an antenna going into it.
And I took bottom cover off today, One cap in
it attached to one end and the other came off somewhere.
All the caps  are the originals, In fact everything looks all original.
Replacing the caps will bring in receive better??
Sorry for all these questions, but I'm new to this.
Rich

[rich]

Can't find    "Slab Bacon's Receiver Road Test"
Rich

[w3jn]

Can't find    "Slab Bacon's Receiver Road Test"
Rich

Here it is.  BTW you can search this forum, see the grey bar above the thread that says "HOME HELP SEARCH ..." :  http://amfone.net/Amforum/index.php?topic=6059.0

The manual is available on BAMA:  http://bama.sbc.edu or if you want a perfect reproduction, our resident member Pete WA2CWA most likely has a reasonably-priced one in stock.

Nationals of this vintage are well-known for their weak power transformers.  IIRC there's a .1 uf capacitor from the power transformer HV secondary to ground that's prone to shorting.  THis will destroy the power transformer.  At the very least you should replace this with a brand-new one (NOT an old unused one!).

Get some De-Oxit contact cleaner and a q-tip and clean the bandswitch contacts (DO NOT spray the De-Oxit directly on the bandswitch!).  That'll probably cure most of any sensitivity/intermittent problems.

An outstanding receiver; one of the best for 75 or 160 AM use.

73 John

[Tom WA3KLR]

Hi Rich,

My father's NC-183D experienced a big loss in r.f. gain also.  I found that the screen dropping resistors in the r.f. amps and i.f. amp stages had gone way up in value.  They are 47 K Ohms.  This was the source of the gain loss.  

There were 2 distinct manufacturers of the 47K Ohm resistors in his receiver.  The finish on the resistor bodies looked different between the 2 makes, one with a shiny surface and the other with a dull, fine-grain surface.  The dull style - all were bad.  

47K Ohms is banded yellow-violet-orange.  Check the resistance of all 47k resistors in the whole radio.

Some of the screen grid bypass capacitors were leaky.

All capacitors and resistors in the audio section were bad also and were replaced.

Good luck,

[xe1yzy]

Hi Rich
Just an Idea...
What kind of speaker have the radio?, as long as I remeber the audio output impedance is 500 ohms in the NC183, if you have a 8 ohms speaker the audio output could be very low.

Good Luck!

[Pete, WA2CWA]

Hi Rich
Just an Idea...
What kind of speaker have the radio?, as long as I remeber the audio output impedance is 500 ohms in the NC183, if you have a 8 ohms speaker the audio output could be very low.

Good Luck!

Audio output on this receiver is 8 ohms or 500 ohms.
It's a nice receiver. I have both the NC-183D and the NC-173. The NC-173 actually seems to have better audio but both work well. As others have said, check the tubes, caps, and the screen resistors.

[Jim, W5JO]

have both the NC-183D and the NC-173. The NC-173 actually seems to have better audio but both work well.

Had a 173 before Pete.  It and nothing but my HRO 60 compare.  Love the National receivers, hate the alignment procedure.  Those damn coils. 

Rich, when you do the alignment, move the coils loops very slowly, just a bit at a time.  It is tedious but well worth it.  Watch out for Pete, he will have you joining ARRL if you aren't careful.  But if he offers you a bottle of old whiskey, it is a good companion to alignment.

[rich]

Thanks for all the replies.
I'm new to all of this and
really like AM. Not sure of all the parts I need to order for this radio.
Is there anyone in NJ that can elmer me on doing this job.
I can bring it to you and learn what needs to be done, or
if I can call someone on phone and tell me what parts and values
to order.  And where to look for parts that need to be replaced in the radio.
Then I can do it myself.
Really looking forward to getting this 183D on the air.
Thanks again for all your time here.
Rich

[Sam KS2AM]

Thanks for all the replies. I'm new to all of this and really like AM. Really looking forward to getting this 183D on the air.
Thanks again for all your time here.
Rich

Once you have it running, are you interested in selling ?    Looks like you do alot of buy/sell if I got the right Rich in NJ.

http://groups.google.com/groups/search?q=ritchi50%40optonline.net&start=0&


Thanks

Sam in NJ

[The Slab Bacon]

Hmmmm............................................

Do we have a "rug merchant" here??

[rich]

No, Not selling.  Want to use it with the Johnson Ranger.

[Sam KS2AM]

Quote from: rich on Today at 10:34:36 AM

Thanks for all the replies. I'm new to all of this and really like AM. Really looking forward to getting this 183D on the air.
Thanks again for all your time here.
Rich

Quote from Sam

Once you have it running, are you interested in selling ?    Looks like you do alot of buy/sell if I got the right Rich in NJ.

http://groups.google.com/groups/search?q=ritchi50%40optonline.net&start=0&

No, Not selling.  Want to use it with the Johnson Ranger.

OK Rich, I must have misunderstood because you said that you were new to all of this but I recall you had a working NC-183D for sale earlier this month.

http://groups.google.com/group/rec.radio.amateur.boatanchors/browse_thread/thread/9428b1275ca5ef79/91f5d4ccd4ca2da6?lnk=st&q=&rnum=26&hl=en#91f5d4ccd4ca2da6

Is the NC-183D from earlier this month still for sale ?   I hope I haven't mixed you up with another Rich.   Maybe I have, whats your callsign BTW ?


Sam  /  KS2AM

[KB2WIG]

Hmmmm............................................

Do we have a "rug merchant" here??

If so, then the IRB treatment...... klc

[rich]

I'm not here to fight.
I'm here to learn.  If you
want to be helpful fine.
Rich

[The Slab Bacon]

I'm not here to fight.
I'm here to learn.  If you
want to be helpful fine.
Rich

Are you here to learn for the enjoyment of the hobby, or are you here to learn so you can maximize profitability??

If you were truely an enthusiast (IMHO) you wouldnt have balked at the thought of putting a little time and money into the referb of the unit.

As KC asked, Do you have a callsign? I may use a pen name here, but just about every amer on the east coast knows mine it is KB3AHE.

Now it is to the point that if you want us to play straight with you, you will have to play straight with us. If you are on the up and up I / we  would be more than glad to help you, if you're not its time to pound sand
                                                                        The Slab Bacon

[Sam KS2AM]

Hi
I just got a National NC-183D Receiver
I turned it on and it seems the RF gain is low.
As you turn up the RF gain nothing is heard til you
get up to to the number 8 on dial.
So no receive until you turn dial up to 8 and I turn it up to 10,
Thanks for reading
Rich  NJ

Hi Rich,

How are you making out with the 183D ?

I've never owned one but I seem to remember seeing a fix for a similar problem.


Sam  /  KS2AM

[W2JBL]

Frank- i thnk this is Rich KF2GG, who actually left the likes of the "Macaroni Net"
to hang with a better class of hams. he's a good American, and wants to learn
more about real radios. fear not Rich- Randy's not here. we will help you...

[ve6pg]

...HEY...LET'S GIVE THE GUY A BREAK...HE NEEDS HELP,SO IF YA CAN,LET'S HELP RICH OUT...TO ALOT OF HAMS THIS OLD STUFF IS A MYSTERY...AND HOPEFULLY RICH WILL GET THE HELP HE NEEDS,AND MAKE A FB AMer...TIM....SK..