Topics

capacitor testers OT

John Griessen
 

On 3/13/20 12:57 PM, Bert Haskins wrote:
I also have a 70+ year old Heath "magic eye" capacitor tester that I use for leakage tests.

I bought this when I was fifteen for use in repairing guitar amps.

It is still quit useful today.
I have a GR cap bridge with magic eye. I think mine needs some repair. I gave it a quick test when I got it
and seemed broken. What is that magic eye tube displaying on a cap tester? How does it differ from a meter
moved by a null detector amp?

Bob Albert
 

It's just a null detector.  That must be a very old model; I don't recall  GR using an eye tube.
Bob

On Friday, March 13, 2020, 08:49:58 PM PDT, John Griessen <@jgriessen> wrote:

On 3/13/20 12:57 PM, Bert Haskins wrote:
> I also have a 70+ year old Heath "magic eye" capacitor tester that I use for leakage tests.
>
> I bought this when I was fifteen for use in repairing guitar amps.
>
> It is still quit useful today.

I have a GR cap bridge with magic eye.  I think mine needs some repair.  I gave it a quick test when I got it
and seemed broken.  What is that magic eye tube displaying on a cap tester?  How does it differ from a meter
moved by a null detector amp?

John Griessen
 

On 3/13/20 11:18 PM, Bob Albert via Groups.Io wrote:
It's just a null detector.  That must be a very old model; I don't recall  GR using an eye tube.
Like this: https://cibolo.com/forsale/box_LG25-C1.jpg
type 1611-B

Bob Albert
 

Wow that's beautiful!  I see it uses a 6E5 tube.  It covers a wide range.  Does yours work?  Is the eye tube bright?  What is the capacitance resolution on the lowest range?
Bob

On Friday, March 13, 2020, 09:44:09 PM PDT, John Griessen <@jgriessen> wrote:

On 3/13/20 11:18 PM, Bob Albert via Groups.Io wrote:
  It's just a null detector.  That must be a very old model; I don't recall  GR using an eye tube.
Like this:    https://cibolo.com/forsale/box_LG25-C1.jpg
type 1611-B

Carl Hallberg
 

Hi all,
Be careful using a magic eye cap tester.  The older capacitor testers were made in an age when the voltage ratings where higher then our present solid state circuit capacitors.  Very easy to ruin a capacitor.
As far as the newer e.s.r. testers, I destroyed mine because of a charge on the capacitor.  I did read the previous comment on a tester that discharges the cap before testing.  Guess I need one of those, but I did build one using two back to back diodes to prevent this.  Can't add the diodes to newer testers because would be part of the D.U.T. (device under test).
Carl Hallberg (W9CJH)

On Saturday, March 14, 2020, 12:57:49 AM CDT, Bob Albert via Groups.Io <bob91343=yahoo.com@groups.io> wrote:





Wow that's beautiful!  I see it uses a 6E5 tube.  It covers a wide range.  Does yours work?  Is the eye tube bright?  What is the capacitance resolution on the lowest range?
Bob
    On Friday, March 13, 2020, 09:44:09 PM PDT, John Griessen <@jgriessen> wrote:

On 3/13/20 11:18 PM, Bob Albert via Groups.Io wrote:
  It's just a null detector.  That must be a very old model; I don't recall  GR using an eye tube.
Like this:    https://cibolo.com/forsale/box_LG25-C1.jpg
type 1611-B

greenboxmaven
 

The Sprauge "Telohmike" condenser tester is one of the best ever made for condensers in tube circuit voltages. The general design was used by Heathkit and Eico, as well as at least one miltary version. They are very good for re-forming electrolytic condensers, you can easily monitor capacitance, leakage and ESR as the reforming proceeds. It's strange how Sprauge made an excellent instrument, but some of the worst condensers of all time. You don't need anything but your eyes to find a bad "Bumble Bee" or "Black Beauty" condenser, if it's there, it's bad. I know a few might still be good, but it's not worth risking a power transformer, scarce tube, or other components.

Bruce Gentry, KA2IVY

On 3/13/20 11:49 PM, John Griessen wrote:
On 3/13/20 12:57 PM, Bert Haskins wrote:
I also have a 70+ year old Heath "magic eye" capacitor tester that I
use for leakage tests.

I bought this when I was fifteen for use in repairing guitar amps.

It is still quit useful today.
I have a GR cap bridge with magic eye. I think mine needs some repair. I gave it a quick test when I got it
and seemed broken. What is that magic eye tube displaying on a cap tester? How does it differ from a meter
moved by a null detector amp?


John Griessen
 

On 3/14/20 12:57 AM, Bob Albert via Groups.Io wrote:
Wow that's beautiful!  I see it uses a 6E5 tube.  It covers a wide range.  Does yours work?
It is needing some repair -- partly working.

Is the eye tube bright?
Sure, bright green.

What is the capacitance resolution on the lowest range?

Don't know until fixed. (Could be a while..)

Bert Haskins
 

On 3/14/2020 7:37 AM, greenboxmaven via Groups.Io wrote:
The Sprauge "Telohmike" condenser tester is one of the best ever made for condensers  in tube circuit voltages. The general design was used by Heathkit and Eico, as well as at least one miltary version. They are very good for re-forming electrolytic condensers, you can easily monitor capacitance, leakage and ESR as the reforming proceeds. It's strange how Sprauge made an excellent instrument, but some of the worst condensers of all time. You don't need anything but your eyes to find a bad "Bumble Bee" or "Black Beauty" condenser, if it's there, it's bad. I know a few might still be good, but it's not worth risking a power transformer, scarce tube, or other components.

       Bruce Gentry, KA2IVY


On 3/13/20 11:49 PM, John Griessen wrote:
On 3/13/20 12:57 PM, Bert Haskins wrote:
I also have a 70+ year old Heath "magic eye" capacitor tester that
I use for leakage tests.

I bought this when I was fifteen for use in repairing guitar amps.

It is still quit useful today.
I have a GR cap bridge with magic eye.  I think mine needs some repair.  I gave it a quick test when I got it
and seemed broken.  What is that magic eye tube displaying on a cap tester?  How does it differ from a meter
moved by a null detector amp?



As a prime example of a really stupid design, when Heath copied the design of the Sprauge they skipped the line fuse..

When the filter cap shorted it was the end of the power transformer.

Three guesses how I found this out.

I've been searching for years for a replacement transformer for my first one.

Needless to say I put a fuse in my second one.


-- Bert