NC300, In the dishwasher.. LOL

[ke7trp]

It looks like I have an ULTRA RARE NC300!   Its serial number 1!!!!    That explains the 600 ohm output. 

Maybe I should ebay this for $1000?  $1500?  $2000?     Then just buy another ham fest special and save it from the scrap heap!

The IF and RF filters where confusing at first..  I had my Brother Transmit on the Champion and I sat in the other room with the manual and played with settings. Once I got it out to 8K wide, I got decent tone out of it. 

This set is SUPER sensitive.  It over loads very easy.  With a 20 ft piece of speaker wire flung over the door, I copied SSbers on 75 meters ulra clear..  They came up to 20DB over.  Its nice to have a Boat anchor with built in SSB.  We sat and listed to them for 20 minutes. No Drift.

Problems I need to address:

1. TONE CONTROL Does not do anything for the sound.. I hosed it with Deoxit. I just cant hear a difference.

2. DIAL DRUM HITS the edge on the Big rotating pulley!.  This Derails the Cord.  To get past 40 meters, You gotta lift the top and help it along.  This one has a Slight bevel to the edge of the Drum.  I wonder if thats factory or not?  I cant see any possible way to adjust this.. It must be slightly warped.. Going to have to file it down a bit so it clears. 

3. I am missing the LEFT SIDE CHROME STRIP.  Never noticed this before.  I thought it was there.. but now its not. Anyone have one? Probably not.. Oh well. It sits next to gear anyways.


On the dishwasher.. DONT DO this when anyone is home..  LOL.   After I was done, I sprayed the dishwasher down with cleaner and ran a Full HOT cycle.  I dont even think that is needed.  This is a new Whirlpool... It was clean inside anyways.

Clark

[KB2WIG]

          " DONT DO this when anyone is home..  "

Clarks's Rule #1

This should be one of the things in the front of the ARRghL Handbook. It saves one from a lot of grief and angst.

klc

[Fred k2dx]

I don't know if this applies to the dishwashing method and antispotting rinse stuff, but after washing a radio I allows follow the last rinse with a distilled water rinse (it's cheap at the supermarket or use water from a dehumidifier) in case your tap water leaves mineral deposits/spots on the item.

[w0ng]

You can find reproduction "donut" polished trim rings for the main tuning knob on your NC 300 from Charlie Talbott, K3ICH. He advertises in Electric Radio Mag and on eBay all the time. They are a perfect fit and absolutely beautiful. Priced at just a few bucks. He has many different polished inserts for many different radios. Shoot him an email for current pricing. You'll be glad you did! 73, Bill, w0ng

[ke7trp]

Yep.. Use distilled water. I also scrub with Furniture spray. Leaves a nice light oil and shine.

I will look through ER for the inlay.. I need that.. Mine is pitted bad.  I saw a guy on ebay. Not sure if that is the same guy. Its a BID auction.

C

[ke7trp]

My 5Y3 rectifier is SUPER HOT.   So hot it made the top of the case very warm in one spot..  This tube is beyond what I would say typical.

Can any other NC300 owners tell if that tube in fact runs real hot?  I better plug this thing into my Eico signal tracer and check current!

C

[ke7trp]

Eico shows 75 watts power consumption.   Manual states 60 APROX.   The Eico is pretty accurate..  My halli said 45 watts and it was right on the 45 line when tested. 

Should I be concerned?? Or just let it run?

C

[N3DRB The Derb]

did you test yer power supply filters? you didnt run them thru the washer too, did ya? That would b a sin.

[ke7trp]

Naw man.. I just tossed the entire radio in.. LOL.


Its got new caps and no hum!

I think I figured it out.. 128 volts at the wall socket!   Put on a variac and she came down.  Man the power company must ramp up during the winter to run everyones heaters.

I put a meter on the Lamp lead and set the variac for 6.3 volts.. It was running the fils up at 7.7 volts.. That cant be good for any of the tubes. 

Clark

[N3DRB The Derb]

yeah that's high line voltage for a set designed for 110.  I was jackin ya about the caps.  I know you done passed thru old radios 101.

[ke7trp]

Actualy its 115 volts     The way I do it, Is to tap onto the Fil line, Normaly the Lamps are on the fil supply.  Then turn the variac down so you get the correct voltage.   On my SP600, This was 117 volts,  On my NC300 this was around 114 to 115 volts.  If you set your variac to 115 your probably good  

C

[W2PHL]

I've done several R-390 RF decks in the dishwasher. Just make sure you pull out all the cans. The gears come out looking like new. Bake in the oven on the warm setting for an hour or two. Just make sure the YL isn't home. She thought I was making dinner. Not!

[Pete, WA2CWA]

National NC-400 receiver has 3.2 and 600 ohm audio outputs. Probably wasn't that difficult for National to tailor a receiver for a specific customer needs even in the NC-303.

[flintstone mop]

No..   Mine has 600 OHM audio output. Its not line out.Its powering the speaker loud. There are no other connections on the back for a speaker.  Just the normal strips for Mute/standby and antenna.  Its not modified. Its clearly original with no extra holes.  I traced this line back to the audio tube directly before we put it in the case because you guys had me wondering.  If I hook the speaker up I get no sound.  If I hook the 600 Ohm transformer up its super lound like it should be.  Not sure what else to say on this.  Maybe they made a few at 600 ohm and then changed them?  Maybe they made some this way to use older speakers? I just do not know.

Someone will probably read this and have an explination.. I am all ears!

600 ohm speaker outpoot YES. AES had nice Hammond transformers for that job.

BTW what does she look like inside???  The cabinet is great!
The NC300 was a little drifty on warm-up

Fred

[ke7trp]

Its all back in the cabinet now. I have not used it much Fred.  Been using the SP600.   I( listed to hams on SSB with some speaker wire antenna. Thats about it.. I need to carry it in here and give it a real test tonight.  I have been busy building my Freq display for my Sp600.  AADE's DFD1.  I got the backlit version.. Works perfect with a simple Tube shield pickup! No wiring or soldering to the RXer!

C

[WQ9E]

My 5Y3 rectifier is SUPER HOT.   So hot it made the top of the case very warm in one spot..  This tube is beyond what I would say typical.

Can any other NC300 owners tell if that tube in fact runs real hot?  I better plug this thing into my Eico signal tracer and check current!

C

Clark,

Rectifier tubes run extremely hot so it is most likely normal.  You will also find the 6AQ5 output tube runs hotter than the other tubes.

 If you didn't already replace them, two "good to replace" caps are the coupling cap to the control grid of the output tube (C-56) and the cathode bias resistor bypass cap (C-62C).  Leakage in either of these will increase current draw of the audio output tube (which is the single biggest B+ current "sink" in a receiver) leading to excess heating of the power transformer, rectifier, filter choke, output tube, and audio output transformer. 

I like my NC-300 a lot; I never have had a chance to try out the NC-303 replacement.

Rodger WQ9E

[ke7trp]

I checked overall current draw and it is exactly what the manual states.  I guess that tube just runs hotter then hell in there.  Its not cherry but its making alot of heat. 

C

[WQ9E]

I checked overall current draw and it is exactly what the manual states.  I guess that tube just runs hotter then hell in there.  Its not cherry but its making alot of heat. 

C

Clark,

If the current draw is good then don't worry and use the radio because AC straighteners do run hot.  Two receiver tubes guaranteed to give you a blister if you touch them are the rectifier and the output tube.  They are generally near each other and as far as possible from temperature sensitive circuits. 

One of my friends from high school got in a bit of trouble with his mother when he decided to do an alignment on the FM tuner section of the family console stereo.  He pulled the chassis out of the cabinet and had it operating upside down on the nice soft living room carpeting.  He decided to look underneath after noticing a scorched odor and when he picked it up there were 4 small and one large circle burned into the cream colored carpet.  You could easily tell where both pairs of 6BQ5 output tubes and the 5U4GB rectifier were located for a long time after that repair job.  He was lucky the Vietnam war was over by that time or his mother probably would have signed him up AND provided some free ammo for charlie.

National kept a lot of the heat out of the earlier HRO's by keeping the power supply external.  My Pierson KP-81 has both the power supply and audio output stage separate from the main receiver so the big heat producers aren't in the same box as the tuned circuits.

[ke7trp]

Hahah.. Funny story.. I did the exact same thing to my moms carpet.. Except it was truly an accident.. I was BIG time in RC cars.. I plugged a battery pack in to charge and set the 15 min timer and left.  The timer failed and it never hit OFF. It fast charged that battery until it scorched the carpet in the living room.  Lucky I did not burn the house down. I was not out of trouble until my dad verified that timer was defective and then stood up for me.

[Carl WA1KPD]

Or have your JN 30 ft of RS mast and 2 meter collinear drop onto the parents roof during a midnite storm when u were 15!

Not a happy parent

[WQ9E]

Carl,

So being a very quick thinking novice, I bet you used this occasion to explain why they needed to buy you 60 feet of "real" tower so this won't happen again 

But now spouses take the place of the parents.  Early one Saturday morning a couple of years ago my wife was slowly waking up when she heard Anna loudly ask, "Daddy, why is your transmitter on fire?"  Maureen came flying into the radio room as I will killing the power to the Desk KW.  One of the cooling fans went up in smoke and created a few minutes of excitement.  My wife went into the kitchen and gave Anna (who was 4 at the time) the fire extinguisher and told Anna it was her turn to babysit daddy to keep him from going up in smoke.

[ke7trp]

LOL..  I had a DC choke in my valiant go out as I took a nap on the couch.  The smoke detector when off and woke me up to a hallway full of smoke..  I always hated lugging that Valiant around.. This time, I picked it up and ran it out side like it was empty cardboard box. That smell was around the house for days and in this room for a week. 

How about reaching over to pick up a Screw driver off the work bench and Grabbing a 50 watt iron directly with your bare hand?


C

[WQ9E]

Clark,

One drawback of the Desk KW is you can't pick it up and run outside with it.  I opened the windows to ventilate before the smoke detector and ADT/fire response got involved. 

After this incident I decided to only use one of the two thumbscrews that lock the works into the pedestal so it is possible to quickly slide out the works and use a fire extinguisher.  One of my colleagues, a former USMC pilot, suggested an on-board extinguisher for the transmitter.

Rodger WQ9E

[ke7trp]

I think the key is to use variacs that are accessable.  If you pull the power to the unit, There is not much inside that will keep burning. Power strips by your foot is a good idea.. Something to kill the power fast. Never leave this stuff running alone.  Turn it off when you leave.. Going to have dinner? Shut it off at the source. NOT the switch on the unit. My Dog turns my Globe king on.  I dont know why.. but he does.  I now have it on a switch so he cant turn it on. I have come back in and found the switch ON again.. Lucky for me, The power was not available to the king.

C

[N2DTS]

I have outlet strips in the bottom of each rack, the one next to the desk also does all the desk top equipment.
The only thing I ever set on fire is the heathkit antenna tuner.

I also have a few large halon fire extinguisers around...

Brett