"Scott W. Harvey" wrote in message
...

[snip]


I have tested brand new electrolytics and have found them to be as
much as 50% off rated capacity. Small coupling and bypass caps, though
are usually right on the money if they're good.

-Scott



That's interesting. I've checked some new electrolytics with my old
Heathkit cap checker, and they are almost always within 20% or so of the
indicated value. I'll check more later and see if it still holds true.

Frank Dresser

A tolerance of +100% -50% was more or less standard on old electrolytic
caps. Today, +50% -10% is customary, but some are still wider than that.

"Frank Dresser" wrote in message
...

"Scott W. Harvey" wrote in message
...

[snip]


I have tested brand new electrolytics and have found them to be as
much as 50% off rated capacity. Small coupling and bypass caps, though
are usually right on the money if they're good.

-Scott



That's interesting. I've checked some new electrolytics with my old
Heathkit cap checker, and they are almost always within 20% or so of the
indicated value. I'll check more later and see if it still holds true.

Frank Dresser

A tolerance of +100% -50% was more or less standard on old electrolytic
caps. Today, +50% -10% is customary, but some are still wider than that.

"Frank Dresser" wrote in message
...

"Scott W. Harvey" wrote in message
...

[snip]


I have tested brand new electrolytics and have found them to be as
much as 50% off rated capacity. Small coupling and bypass caps, though
are usually right on the money if they're good.

-Scott



That's interesting. I've checked some new electrolytics with my old
Heathkit cap checker, and they are almost always within 20% or so of the
indicated value. I'll check more later and see if it still holds true.

Frank Dresser

Frank Dresser wrote:
"Scott W. Harvey" wrote in message


I have tested brand new electrolytics and have found them to be as
much as 50% off rated capacity. Small coupling and bypass caps, though
are usually right on the money if they're good.

That's interesting. I've checked some new electrolytics with my old
Heathkit cap checker, and they are almost always within 20% or so of the
indicated value. I'll check more later and see if it still holds true.

Electrolytics are usually rated for -10%, +50% tolerances, and most of
them will measure higher than the package says. Check the data sheet
on the caps.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Frank Dresser wrote:
"Scott W. Harvey" wrote in message


I have tested brand new electrolytics and have found them to be as
much as 50% off rated capacity. Small coupling and bypass caps, though
are usually right on the money if they're good.

That's interesting. I've checked some new electrolytics with my old
Heathkit cap checker, and they are almost always within 20% or so of the
indicated value. I'll check more later and see if it still holds true.

Electrolytics are usually rated for -10%, +50% tolerances, and most of
them will measure higher than the package says. Check the data sheet
on the caps.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

In article , "BFoelsch"
writes:

For testing boatanchor-era caps, I would strongly suggest that you get one
of the same-era capacitor bridges that let you test with real voltage
applied. I like the Heath, but I have also used the Sprague and I am sure
many others are just as good.

I use the venerable Eico 950A bridge and leakage tester. You can dial up any
voltage up to around 500 and observe leakage on the magic eye tube; for
'lytics, a neon bulb in series is subbed for the eye tube. Once you charge the
cap up to rated voltage, the eye or bulb should show nothing.

Great for reforming lytics too. And the bridge is pretty accurate for
measurements.

But still, before cutting one end loose to check it, I find it worthwhile to
check grid and screen voltages in a radio to see if a cap is really leaking
enough to throw things off. --Mike K.

Oscar loves trash, but hates Spam! Delete him to reply to me.

In article , "BFoelsch"
writes:

For testing boatanchor-era caps, I would strongly suggest that you get one
of the same-era capacitor bridges that let you test with real voltage
applied. I like the Heath, but I have also used the Sprague and I am sure
many others are just as good.

I use the venerable Eico 950A bridge and leakage tester. You can dial up any
voltage up to around 500 and observe leakage on the magic eye tube; for
'lytics, a neon bulb in series is subbed for the eye tube. Once you charge the
cap up to rated voltage, the eye or bulb should show nothing.

Great for reforming lytics too. And the bridge is pretty accurate for
measurements.

But still, before cutting one end loose to check it, I find it worthwhile to
check grid and screen voltages in a radio to see if a cap is really leaking
enough to throw things off. --Mike K.

Oscar loves trash, but hates Spam! Delete him to reply to me.

BFoelsch wrote:
A tolerance of +100% -50% was more or less standard on old electrolytic
caps. Today, +50% -10% is customary, but some are still wider than that.

You've got to look long and hard to find any with that loose a spec
anymore. I just paged thru the Mouser catalog and a quick glance sez
everything offered is +/-20% except for the old Vishay/Sprague TVA-Atoms
and Littl-Lytics.

-Bill

BFoelsch wrote:
A tolerance of +100% -50% was more or less standard on old electrolytic
caps. Today, +50% -10% is customary, but some are still wider than that.

You've got to look long and hard to find any with that loose a spec
anymore. I just paged thru the Mouser catalog and a quick glance sez
everything offered is +/-20% except for the old Vishay/Sprague TVA-Atoms
and Littl-Lytics.

-Bill

"Frank Dresser" wrote in message
...


Here's the results, checked on a Heathkit IT-28:

BC HP 68ufd 200V
68-62-60

BC HP 47ufd 200V
43-44-46-44-44-43-45-45

BC HP 33ufd 200V
33-30-29-31-31-30-33-32

Xicon 47ufd 160V(Marked +/- 20%)
44-43-43-46-43-44-48

Xicon 33ufd 160V(Marked +/- 20%)
32-34-34-34-34-32-33-32

Panasonic 47ufd 450V
45-46-43

Ducati 100ufd 25V (about 30 years old)
98-100-100-98-105-95-105-102-110-100-110

Planet Liticap 40ufd 450V (used pull, maybe 40 years old)
38

Frank Dresser