[TenTec] Fragile Radios

[Steve Berg]

Thanks for the tip.  I'll look into replacing the electrolytics in the 
rig.  I have replaced many of the old paper caps over the years.  One of 
the more interesting examples of this was an old Hallicrafters TO keyer 
where the speed tracked the ambient humidity level.  I replaced all the 
black beauty caps, and it has worked great ever since.  It has taken me 
a while to appreciate the Omni V. For many years I have run an Argonaut 
II and it is much easier to use.  Works rather well, too.  But, I am 
assured by some that the Omni has a much better receiver and I have put 
the trusty Argo to work as the IF rig in my VHF setup.  I'll start 
replacing caps and see where that takes the radio.  Then, I can put the 
Autek filter back on the Drake 2B or the Gonset G-76.

Steve WA9JML

Dr. Gerald N. Johnson wrote:
> On Wed, 2007-09-12 at 23:20 -0500, Steve Berg wrote:
>> I have a really nice Omni V and have never been able to make much use of 
>> the audio filter in the rig. Instead, I use a Autek external filter to 
>> good effect.  Does anyone here know if this could be a problem with 
>> older electrolytic caps? Since I plan to use this rig for many more 
>> years, would it be advisable to recap it like Joe has suggested?  I also 
>> have done this many times with my older boat anchor radios.
>>
>> Steve WA9JML
>>
> Some varieties of miniature electrolytics have a high power factor when
> new and fresh. Many were not well made. There was once a period when
> nearly every computer mother board had bad capacitors because some
> Chinese lowest price maker didn't make the right and they couldn't stand
> rated operating voltage or even a fraction of it. But tended to short
> and eject their guts.
> 
> I've been testing miniature electrolytics for several years with a
> modified Heathkit capacitor tester that has power factor on two of the
> capacitance ranges. I've found no used miniature electrolytics with good
> power factor and the most commonly available new ones not better. The
> low ESR and high temperature range capacitors measure significantly
> better.
> 
> I'm of the opinion that in time, if not now, many solid state vintage
> radios need every miniature electrolytic replaced, just like we replace
> molded oiled paper capacitors for their inherent leakage. And like those
> oiled papers, I don't think its worth the bother to test them, just
> replace them. Even the low ESR parts aren't expensive.
>