Cleaning 1942 Military Radio

I am starting to restore a US Navy WWII National Radio from 1942 and wanted to find out the best way to clean the interior and all the components. I have a large ultrasonic cleaner I use for other projects. Any advice would be greatly appreciated!

Thank you!

Welcome to the TechForum Community.

We have several cleaners here depending on the application you will have to read over the datasheet. For a suggestion, please look at ES2400 and datasheet Compatibility materials are listed on page 2 of the spec. It is a very flammable product so keep away from sources of ignition and energized equipment.

Hello g.didio,

Be very gentle.

For example, here is a Joint Army Navy (JAN) type 807 (VT-100-A) vacuum tube from my collection. This was a popular WWII transmitting tube. A pair is good for about 100 W.

You will note that the 807 octagonal stamp is still visible. A modern cleaner with any “active” ingredients would quickly pull the writing off the tube’s glass.

Silly Things: My boy once had some Legos minifigures. He had colored them with a permanent marker. I found that a wipe of acetone would remove the marker nicely. So, we did the right thing and pored several bottles of acetone into a container with all the minifigures and shook it for a few minutes. Turns out acetone is really good at removing markers from Legos. It’s also really good at removing Lego from Lego. The result was a blob of melted plastic.

What I’m trying to say is don’t clean too hard or you will lose a good deal of character. That ultrasonic cleaner is to an antique radio as acetone is to Lego.

May I recommend Mr. Carlson’s videos - link below. He has an extensive collection of restoration videos. Spend some time and you will likely learn a trick or too.

Best Wishes,



Thank you so much. This is exactly why I asked rather than just diving in. I do not know if the old tubes are still good, but I do have a tube tester I can use. Would rather keep the originals.


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Good Luck, Gary.

For fun!

Not many of us can see we have a tube tester!



P.S. Please send before and after pictures of your radio.

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Nice Eico tube tester, Aaron! The one I have is an EMC unbuilt kit I acquired in 2008 for $130. Since it is an unbuilt kit, I may purchase another to use. Here are some pics of the radio:

Very nice, Gary.

Thank you for the pictures.

Yes, unbuilt kits are like hen’s teeth. One of those rare cases where building the kit lowers the value. On the other hand, there is some joy in building them.

I do hope you like Mr. Carlson’s video as one of his latest projects is similar to your radio.

Keep in touch,


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Hi Aaron,

Thought you would appreciate some pictures of my progress. Taking things very slowly as I don’t want to mess anything up!


Hello Gary,

Very impressive machine!

This is my favorite picture from your collection as it shows the band select tuning coils and trimmer capacitors.

Do you plan on replacing all of the Sprague wax paper capacitors? Chances are very high that the majority are electrically leaky after 82 plus years.

Have fun with the project.



Hi Aaron,

I was pretty impressed when I removed the catacomb, took the cover off, and saw all the tuning coils. It’s amazing to me how the receiver was engineered and how far the industry has come.

I was able to get in contact with a gentlemen who specializes in this receiver. He is maintaining a log of all the serial numbers and has added mine. He gave me tons of advice on restoring and suggested I leave the capacitors for now and only replace when they begin to short by monitoring the load resistors. I purchased a B&K 1655A Analog Isolated Autotransformer to use when initially powering up the receiver to make sure I don’t fry anything! Just need to take my time.

Good news is all the tubes tested strong. My plans right now are to simply clean everything, re-paint the outside shell, replace lamps, install a new power cord, install a new dial cover (I purchased some Lexan at Home Depot that just needs to be cut), and install some rubber feet on the bottom. Hopefully I won’t need to replace any capacitors because there are a lot!

Hope all is well in your world!


Thank you, Gary.

That’s excellent news, so glad you found a specialist.

Yes, the B&K 1655A is very useful for this type of work. You can bring the radio set up slowly while monitoring the current. Also, you can check for AC line leakage on the chassis to verify the safety of the unit.

Yes, that’s been my experience. The tubes are generally strong.

BTW, I have a post WWII Hammarlund HQ-150. Is a civilian set, but its military roots are showing. It’s very heavy. Internally it’s a work of art. Also, after it has warmed up, it’s stable enough to tune in ham SSB conversations.

Have fun with the restoration.



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