DR Radio Capacitor 1947452

[D S.]

The wire came out of my radio capacitor like a fuse out of a firecracker. What do these attach to inside? Can it be reinserted and made to work?

Thanks,
Scott Sims
Texas Chapter

[Jack H.]

Re: DR Radio Capacitor 1947452

The wire was 'contact welded' to the surface below the phenolic insulator. Over the years vibration, handling and oxidation of the exposed bare stranded copper makes the interface brittle and prone to fatigue fracture.

Later, service replacement capacitors have a rubber 'cone' surrounding the lead wire to thwart side loading and subsequent fatigue fracture. Unfortunately, those have different PN's and are visually distinguishable from the factory originals during judging.

You CAN repair the lead wire IF you're good at soldering. The approach is to thoroughly clean the surface of the capacitor beneath the phenolic insulator (through the lead wire hole), daub a little flux down there and use a SHARPLY pointed soldering iron to 'tin' the top of the cap body through the lead wire hole.

Next, clean and trim the end of the broken lead wire SHORT, dip it flux and tin it as well. Gently clamp the body of the capacitor so it can't move. Insert the freshly tinned lead wire through the phenolic so that it's in contact with the tinned capacitor body surface below and insert your soldering iron.

You want to melt the tinned lead wire onto the tinned capacitor end cap. It'll take time for the end cap to absorb heat and solder to flow evenly between the two pieces! An illuminated magnifying glass helps to see what's happening.

When you have fresh, liquid solder re-flow covering both the lead wire stub and the capacitor end cap, hold the lead wire VERY still and remove your soldering iron. When the solder has solidified, your repair is complete.

Do 50 or so of these repairs and you get good enough that it's hard to see the repair job! Expect the repair to show (a visible 'blob' of solder) on the first few you work on...

[D S.]

Re: DR Radio Capacitor 1947452

Thanks, Jack. I have only this one to practice on. I'll give it a try.

[Jack H.]

Re: DR Radio Capacitor 1947452

An alternative is to know somebody who works in hi tech electronics and has access to a manual, surface mount, solder repair station. With that kind of technology, laying down a precision re-flow minature solder is child's play...

Since you're in Texas, the next question is whether you have and techie friends working at Texas Instruments, Dell, or Compaq/HP?

[Bernard M.]

Re: DR Radio Capacitor 1947452

See the article on repairing them in the current Restorer on pages 36-37. The article has photos of the internal construction to help you understand how they were assembled and details a method to repair them.

[D S.]

Re: DR Radio Capacitor 1947452

Thanks. Which issue? I haven't gotten a Restorer in a while so I assume it follows or comes with the Driveline which I got that yesterday.

[John H.]

Re: DR Radio Capacitor 1947452

Thanks. Which issue? I haven't gotten a Restorer in a while so I assume it follows or comes with the Driveline which I got that yesterday.

Fall issue - came a couple of months ago.