KØFF Homebrew Tips

Restoring Boatanchor Radios
Replacing Components the Easy Way

Anyone who restores or repairs Vintage Radio gear knows that capacitors and sometimes resistors often need replacing. It would be safe to say that in any old radio gear, capacitors DO need to be replaced. These sets were built using point-to-point wiring and terminal strips as well as tube sockets with terminals on the back. Connections were ALWAYS made mechanically sound before soldering, by wrapping the wire through the hole in the terminal and clamping down on it. If there were but one wire on the terminal, there is no real issue, you would just remove the whole wire and replace the component with a new one.

If you are like me, falling prey to Murphy's Law all the time, the wire you really want is under 5 or 6 other really heavy wires that don't need to come out. In this situation we use a little spiral of wire, interwrapped with small gauge solder. These are prepared ahead of time using a pin or similar form with a diameter close to that of the wires being spliced. Once the little cylinders of solder+wire are prepared, it is very simple to clip the old component out, leaving adequate lead length in the set, then splice in the new component. Just like doctors the vintage radio restorer's first rule is "Do no harm!". Following is a picture demo to show the steps.

Fig. 1- Typical point-to-point wiring technology:

Fig 2 - Clip out bad component. Also shows wire and solder material to make spiral:

Fig. 3 - Wind wire and solder on form, interleaved:

Fig. 4 - Cut spiral to correct length needed:

Fig. 5 - Right side soldered, left side ready to heat:

Heat shrink tubing could be used to dress up the joint but this would not be "period correct". These spiral solder splices are absolutely period correct.

Happy Building, Geo KØFF

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Restoring Boatanchor Radios

by K0UA on January 20, 2010 Mail this to a friend!

Excellent, I hadn't thought of doing that!
Thanks,
Jim
K0UA

Restoring Boatanchor Radios

by KG4QPQ on January 20, 2010 Mail this to a friend!

I can remember back in the day when the local TV repair parts distributor used to have the spirals with solder already on them. You would just slip them in place and heat. They are indeed period correct.

Restoring Boatanchor Radios

by W4LWZ on January 20, 2010 Mail this to a friend!

Thank you for a brilliant, elegant, way to make a restoration easier. I am about to start on a couple of restorations ans will use this method to replace a number of leaky caps.

Restoring Boatanchor Radios

by K8CIT on January 20, 2010 Mail this to a friend!

A great idea from the past, and just in time for me. I am starting the restoration of a 1939 Zenith 15 tube radio. I need a whole bag of these. I wish I could buy them instead of making them. I made one this morning and it works FB just like it always did. Thanx for the memory...

RE: Restoring Boatanchor Radios

by AD4U on January 20, 2010 Mail this to a friend!

As someone who restores boat anchor HAM radios and Broadcast radios from the 1930's - 1970's, I found your article interesting and informative.

However I have found that a PROPER solder connection without twisting wires etc is more than strong enough to be mechanically and electrically sound.

What I do is clip out the old component, leaving enough of the old wire to solder to. Then I parallel the wires of the new component about half an inch along the old wire and let the solder flow.

Your way is definitely much more secure electrically and mechanically, but I have never had a problem doing what I described and it is much faster.

Thanks again for a great article.

73 Dick AD4U

RE: Restoring Boatanchor Radios

by K9FV on January 20, 2010 Mail this to a friend!

Well presented and clearly demostrated. GOOD JOB!!! and I WILL remember. While I have held the wires parallel and soldered, sometimes it's hard for my shaky hands to be steady enough. That method solves the problem.

Thank you again.

73 de Ken H>

Restoring Boatanchor Radios

by K1DA on January 20, 2010 Mail this to a friend!

I use the AD4U approach since my stuff needs to work but is NOT going back to severe duty. Sometines I bend a very small loop in the new component leads and slide it over the remaining lead from the (carefuly) clipped out part.

RE: Restoring Boatanchor Radios

by KG6YV on January 20, 2010 Mail this to a friend!

Excellent article, great pictures and a very effective technique to replace components in a point to point chasis. I have been using a small "number drill" for years to make the needed spirals and it seems to work well for typical component wire sizes.

Thanks for passing on the expertise to so many thru the Eham article forum...

Greg
KG6YV

RE: Restoring Boatanchor Radios

by KC8VWM on January 20, 2010 Mail this to a friend!

Then I parallel the wires of the new component about half an inch along the old wire and let the solder flow.

Your way is definitely much more secure electrically and mechanically, but I have never had a problem doing what I described and it is much faster.

Thanks again for a great article.

73 Dick AD4U

----------

I have done the same thing but I use "silver" solder because it increases the mechanical strength of the parallel connection. However, I reserve this method to situations where I would otherwise have to dissemble something to install the part.

However, in most cases like in the photos above I would just unsolder the old part and install the leads from the new part through the solder tabs. I also do this because I like to "hit" the old tired solder on the tabs with a soldering iron which tends to "renew" the solder tab connections.

Always enjoy reading these sort of articles.

My Best es 73 de Charles KC8VWM

RE: Restoring Boatanchor Radios

by AB3EO on January 20, 2010 Mail this to a friend!

A trick I have used when replacing components on these radios is to use a short jumper wire with alligator clips. This gets clipped to the two attachment points before the old component is removed. This is just a place holder to make sure the new piece is attached to exactly the same lugs as the old one.

While the open chassis's are easy to work on, unlike a PC board they aren't labeled and it's easy to lose your place if you look away for a moment.

RE: Restoring Boatanchor Radios

by WB2WIK on January 20, 2010 Mail this to a friend!

Cool idea!

RE: Restoring Boatanchor Radios

by G3LBS on January 21, 2010 Mail this to a friend!

George thanks again for excellent advice and photographs.
If aspiring hams followed your tips as exercises in a practical experimental course they would be better- trained hams.
More please.

Restoring Boatanchor Radios

by N8CMQ on January 21, 2010 Mail this to a friend!

Do not use this technique in high vibration applications, such as mobile service.
I have used this type of repair in the past, and it is fine for any other application.
If I were to have a terminal that I did not feel comfortable trying to remove the old lead, I would trim it close and add the new component.
But each time you go to repair a radio, something new crops up to teach us new tricks!

RE: Restoring Boatanchor Radios

by K9MHZ on January 21, 2010 Mail this to a friend!

Agreed. I've never had a problem with solderwicking a terminal, and then removing the entire lead of an old component. Then, you can thread the new component's lead through the terminal, and make a solid mechanical connection before resoldering the terminal.

Mileages vary.

Brad,
K9MHZ

RE: Restoring Boatanchor Radios

by KC8VWM on January 22, 2010 Mail this to a friend!

I'm not convinced if a "mechanical connection" is always required in every case.

Seems to depend on the circuit. For example in an amplifier Pi circuit which generates enough heat to melt the solder I can see a mechancial connection as beneficial, however in a Hartley oscillator is probobly less critical and the authors suggestions would work fine.

My Best,

Charles - KC8VWM

RE: Restoring Boatanchor Radios

by N8BOA on January 22, 2010 Mail this to a friend!

Ah yes the smeel of burnt carpet now I remember.

Restoring Boatanchor Radios

by N1TCH on January 22, 2010 Mail this to a friend!

I wish I had seen this about 3 years ago when I struggled with recapping a S-53A. Now I'm ready to tackle my S-40B!!

RE: Restoring Boatanchor Radios

by K9MHZ on January 23, 2010 Mail this to a friend!

If you have a radio that's melting solder in its pi network, a solid mechanical connection is the least of your concerns.

RE: Restoring Boatanchor Radios

by KC8VWM on January 23, 2010 Mail this to a friend!

Yes actually you would have more of a concern and that is exactly why one can prevent further damage from occuring by ensuring a mechanical connection exists "in case" there is a condition where it causes the solder to melt.

I believe this is all explained in the ARRL manual under the homebrew amplifier construction section.

Do you have a copy?

73 de Charles - KC8VWM

RE: Restoring Boatanchor Radios

by K9MHZ on January 23, 2010 Mail this to a friend!

I think you're making my point.

Restoring Boatanchor Radios

by N4BWV on January 24, 2010 Mail this to a friend!

This is pretty labor intensive. If you don't care about aesthetics just forming a u in the new and old lead, crimping together and and soldering works fine for me.

RE: Restoring Boatanchor Radios

by K4KYV on January 28, 2010 Mail this to a friend!

This has long been one of my pet peeves. I couldn't count the times I have cussed a manufacturer or a previous home builder for making a "solid mechanical connection" before solder was applied. I have never seen a soldered connection where a simple hook was made at the end of the wire before it was inserted, or the straight wire was simply stuck into the hole in the tab, and solder was PROPERLY applied, that the wire itself wouldn't fail from metal fatigue long before the soldered connection could be made to work loose. Inevitably, un-doing the solid mechanical connection results in heat damage to other components, the terminal strip and the insulation on the wires.

Perhaps in assembly line production where one person attaches the wiring and another applies solder would require the solid connection to keep the wired assembly from falling apart before it reached the solderer, but for home construction where each connection is soldered immediately after the wire is attached, there is absolutely no need to do this. This is especially true with trial-and-error homebrew projects which may likely need un-soldering and revision several times before the final circuit is achieved.

Absolutely the worst is when the wire is inserted into the hole in the tab, pulled through, re-inserted and pulled through several times so that 4 or more turns of wire are wrapped between the hole and the edge of the tab. Unfortunately, this technique was not uncommon, particularly with old military gear.

Restoring Boatanchor Radios

by KI5BC on February 1, 2010 Mail this to a friend!

What guage wire is that? Looks like wirewrap. I have a few older beauties to recap, and this is very timely. Thanks for your expertise!!!

de....Rynn

Restoring Boatanchor Radios

by KG6UTS on February 2, 2010 Mail this to a friend!

A while back I picked up a factory assortment of 'RedHead' high voltage mica capacitors that came with the spirals in the boxes with the caps.

EdZ KG6UTS

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Restoring Boatanchor Radios
Replacing Components the Easy Way