A few days back, I was in the process of replacing the batteries in my “every day use” radio.
It is a National Panasonic transistor radio, Model R-210J. While I had the back off, I thought that I should take the time to check, and replace any electrolytic capacitors that were found to be no good.

What I found shocked me. The little radio is fifty-one years old. What could possibly be wrong with the caps? I do use it every day. What I found is that four out of the five electros in the set were either open completely, or high E.S.R. Then how was it that I have been able to use it every day?

I had suspected that the A.G.C. Filter cap was poor, as I could at times, on some stations, get a slight distortion (overload). When those stations were slightly mis-tuned, the sound quality improved.

The other thing I did notice, was that when the volume was very low, there was a slight distortion, that sounded like a slight poling of the speaker.

So there we have it. If I, and my, “Golden Ears,” were mostly unaware of a anything wrong, how bad would the caps had to be before “Joe Public” would have complained?

Happy New Year to all.

Wayne.

With a battery transistor the biggest use of electrolytics is in coupling & decoupling (not so much RF) I find a lot of couple caps are causing loss of volume as they dry out and the capacity falls.

Where there is wholly no AC source as there is in a mains set They are less likely to forget the words & hum.

The main reason that I always advocate replacing all electrolytics, is (as you have found,) that even in valve radios, cathode bypass electrolytics also loose form, not just the "B" filters.

I would also pay attention to any tubular brown, or black caps ("Hunts" being one), around 3/8" dia & 1/2" long. Cracking of the jacket & shorting, or going open as a result, is never unusual

Sometimes as the radio ages the sound of it as perceived by you, will change with it & not be noticed.

The electrolytic filtering the AVC line is often used as an IF bypass cap as well. And when its ESR goes bad, it becomes a poor IF bypass, sometimes this allows the IF amps to oscillate or lose gain. So I'd replace it along with the other electrolytics.

Similar to my point. Electrolytic caps are poor passers of RF at the best of time & it was never unusual in valve sets to see one with a cap from 0.5mfd to 0.1mfd parallel to it.

I have heard the story, actually corroborated by a witness that some of the smaller Asian manufacturers would routinely clip out components on their first sample until it became noticeable, then put last one back in, in an effort to reduce their component count.
Looks like that never happened on yours!

Also, I notice many electronic gear has capacitors with more capacitance than actually required, higher volt rating than actually required-reforming to lower operating votages with more capacitance. This boosting reliability also.

That was also a joke about Astor. HMV would build them by the book & normally well, & Astor would build them, remove parts until it stopped, put the one that killed it back & then put it into production.

They also seemed to use the worst grade of rubber insulated wire. Tasma had a better idea, they overloaded the wire on the heaters in some models & cooked it.

I would not be surprised if "Notre Dame" was wired with "Cloth rubber" insulated wire (& we still have it in houses here) and it was "disturbed" during the renovations, causing the insulation (by now rotten) to catastrophically fail: Arc & start the fire.

One must be careful with valve rectifiers & capacity. Too much would strip the cathodes. The early Electrolytic caps had massive tolerance margins. Also with filament rectifiers and anything behaving like 5Y3 / #80. There was a massive surge (twice EMF) if there were heaters, it then being dragged down as the heaters caused the valves to conduct. Caps had to withstand that surge.

That's a clever observation re Notre Dame, seems to make sense, I have seen that old type cable...

QUOTE: I have heard the story, actually corroborated by a witness that some of the smaller asian manufacturers would routinely clip out components on their first sample until it became noticeable, then put last one back in, in an effort to reduce their component count.

That story has been doing the rounds for decades. I first heard it when I was a trainee, except it was told about 'X' manufacturers, where 'X' ranged from the local competition to giant Japanese factories.

It may well be the stuff of urban legend...

I have seen radio circuit boards where a number of components are labelled on the board with holes, solder pads empty, and there are no components fitted, and the radio works ok!

It was VIR wiring that caused the fire at St Mary's Church in Concord, about 25 years ago now. That church had blue neon crosses on the roof and it was one of these which lead to the fire - all too familiar, requiring the roof to be completely reinstalled. St Mary's is one of Australia's largest non-cathedral churches and there was plenty of timber in its construction and at that time there was a mix of hardwood and cedar in roof construction. Cedar burns like petrol at that age. As far as I recall, the original roof was slate which meant that there would have been even more timber there to support all the slate. The new roof is iron and during the refurbishment they took the time to rewire the building - a good opportunity to ditch the rest of the VIR.

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A valve a day keeps the transistor away...

There appear to be two suspected causes of the Notre Dame fire.

https://www.nytimes.com/2019/04/25/world/europe/notre-dame-fire-investigation.html

The first is the wiring of the bells in the spire and roof space. These were electrified 2007 and 2012.

The other is fire from cigarette butts, these having been found on the scaffolding.

A quote from the above link indicates the vulnerability of the roof structure to fire:

"The vast majority of church bells in France, to be sure, are electrified. But only Notre-Dame had the forest — there was no comparably complex assemblage of ancient dried wood, some of it dating to the 13th century.

Anything similar had already burned, experts said, and on the night of April 15, Notre-Dame’s beams, too, joined that destiny."

The construction of the old pre-new Iron age constructions we have now, was always going to be an issue. Even wood has a fatigue life & with Notre Dame they had planted some trees to cater for that.

We had a similar incident with St Mathews Albury where the roof incinerated. With rapid action from my cousin (Builder) they saved the walls & it was restored.

That also raises the fake news re Notre Dames walls. These were designed by "Genius". The "Flying Buttress:" is designed to hold up the walls, to enable them to put in those big windows. If you got the buttress wrong they fell down,many did & some English one's are in strife because they stuffed up.

However, because Notre Dame's walls are "vaulted" those walls are designed to not fall down. Is had fires before.