[ARC5] Receiver current drain (best operating voltage)

[Kenneth G. Gordon]

>From what I remember, the working voltage of the small can-caps was pretty 
marginal: I think it was something like 300 VDC.

In any case, they are all impregnated with beeswax which over the years, 
has somehow reacted with the metal in the can, or the solder, to form that 
green glop with which we are all familiar. Also, a lot of the beeswax has 
melted and run out, leaving a mess on the bottom plate, and the caps even 
more marginal.

At this late date, it is practically impossible to find a completely good can-
cap, and that triple 0.22 job in the back is always shorted.

Short of running the receivers at very reduced voltage (assuming the caps 
are still good at the lower voltage), about the only solution in my opinion is to 
restuff the caps...but that seems to me to be, somehow, a bit dishonest, not 
to mention hard work, to make the result look "un-restored"

I did some experimenting a few years ago with what was then an NIB 
receiver still in its original shipping box. I found that the best, and most easily 
achieved voltage to run that one on was 180 VDC. This resulted in far less 
heat, greater stability, and no noticeable difference in sensitivity, or audio 
output, but considerably reduced internally generated noise.

I also know of those who run them on 24 VDC, but, when I tried that, the 
audio output level was extremely low, the receivers took "forever" to stabilize, 
sensistivity was down noticeably, and the only advantage I could determine 
was that it allowed some of those very marginal can-caps to somewhat work 
for a bit longer.

To me, 60 VDC and 90 VDC are in the same category.

So, what do you guys do about this if you want to install the receivers in a 
warbird, for instance, in working condition?

BTW, I consider the ARC-5 series to be, without doubt, the finest single-
band receivers ever built.

Ken Gordon W7EKB