Paper capacitor and Hallicrafters S-40A notes
 

Antonio Vernucci wrote:


By the way I also have an HT-40 and found no need for changing
capacitors, as the leaky capacitors are placed where they make no harm
(e.g. screen grid bypass).

73

Tony I0JX
Rome, Italy

I always consider 'leaky' to mean that they are somewhere along the road
to 'short' and just haven't arrived yet. Leakage, particularly on HT
circuits, will ultimately lead to heating and then is just a matter of time.


I figure we all have a certain mental tolerance of how much we can live
with in a certain part of the circuit but the other factor is 'time'.
Same applies to drifted carbon resistors.

-Bill

Paper capacitor and Hallicrafters S-40A notes
 

I always consider 'leaky' to mean that they are somewhere along the road to
'short' and just haven't arrived yet. Leakage, particularly on HT circuits,
will ultimately lead to heating and then is just a matter of time.

You are certainly right in saying that changing the leaky capacitors would be
the correct way to go from the technical viewpoint.

However I adopt a different phylosophy. I use the HT-40 (or other boatanchors
radios) for maybe a few hours per year in total, just for fun. For normal
operations, I use recent equipment.

So, the risk of failure caused by the HT-40 leaky capacitors is moderate. On the
other hand, if I would replace the leaky capacitors, I would have the certainty
(and not just the risk) of spoiling the originality of the radio.

So, in the end I prefer to leave the radio as it is, as long as it works
acceptably.

73

Tony I0JX

Paper capacitor and Hallicrafters S-40A notes
 

So, the risk of failure caused by the HT-40 leaky capacitors is moderate.
On the
other hand, if I would replace the leaky capacitors, I would have the
certainty
(and not just the risk) of spoiling the originality of the radio.

I am of the opinion the originality of the radio has been compromised when
the caps (and other parts) go bad and do not perform up to original
engineering intent. Like a Fender Stratocaster or Les Paul with an old leaky
bubble bee cap that sounds nice, mellow, fuzzy...(insert description). It
did not sound that way from the factory either. This old bubble bee is a
whole new sound. Pleasing and desirable, perhaps, but not original.

And there is the engineering part of me that says if it is not operating
with in spec it is broke.

But this is a whole other philosophical discussion.

Just my opinion,
Paul P.