Douzahn You are commenting using your WordPress. I was blown away by how well kept it was, and went there to pick it up and manuual amazed to see the amount of electronic instruments he had — collections all the way from They say nobody usually comes for those stuffs anymore. In addition, manula files are archived, so you need WinZip or WinRar to open that files. So I started fixing it. It can kill you. Sometimes, in the process of looking for something, you come across a few folks, who possessed a wide spectrum of skills and abilities.
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It also can check a capacitor under its actual operating voltage, a feature that makes it very handy for restoring vintage tube radios and TVs. After cleaning the controls and replacing a few capacitors, it works like a champ. Below is a photo of the device in action. The "orange drop" type cap is mounted in test terminals at the right.
The Range selector is set to the appropriate capacitance range. The green "magic eye" indicator is seen at the upper right. As you turn the big middle pointer back and forth, the magic eye will be closed for most incorrect values in the chosen range.
At lower left is the Voltage control. As the capacitor charges up, you will see the crescent close momentarily and then reopen when the cap reaches full charge. If the crescent remains closed all the way when you reach the rated voltage, the cap is too leaky to use.
Testing a capacitor under voltage is what makes this bridge so valuable. A modern multimeter may test capacitance, but the voltage that it applies is miniscule compared to what the capacitor will experience in a tube radio or TV.
Old caps might look fine using a modern multimeter, yet leak badly at operating voltage. Only a checker of this type can provide a meaningful real-world test.
Before testing a capacitor in a radio or TV, you must disconnect one of its leads. The left side of the panel has a second set of terminals labeled Comparator. When you turn the Range control to Comparator, you can connect a component of known value to these terminals and then compare the value of a component connected to the right terminals.
One case where you might do this is where precision is important. In the left terminals you would connect a component with exactly the right value. In the right terminals you would test all of the replacements in your parts bin and select the one whose value is closest. Refurbishing the B Like any s tube device, the B should be restored before use. This typically means cleaning its controls with DeOxit and replacing its paper and electrolytic capacitors.
EICO products were available either as a kit or pre-assembled from the factory. In the previous photo, I had already replaced some of the old paper capacitors with new yellow ones. The next photo shows two old electrolytics that will also need replacement. The big tan one 8 mfd has an unusually high voltage rating: volts. As you can learn in my capacitor replacement article, wiring two identical capacitors in series results in half the capacitance and double the voltage rating.
This creates an mfd cap with a volt rating, more than adequate. In the next photo, I have removed both electrolytics for replacement. One end has been snipped free, and I stretched out the cap to reach the other end. The big pointer is held to its shaft with a setscrew.
If, after recapping, your pointer appears to be off by the same amount across the scale, just loosen the screw and adjust it. Apart from tube failure, not much else can go wrong with this simple device. If higher precision is desired, you can try the Comparator function as noted earlier. If you need very high precision, then you should not be using a service-grade tester in the first place. The failure rate for old paper and electrolytic capacitors is so high that testing them is a waste of time.
As the saying goes, I generally test old papers and electrolytics by listening for that satisfying Clang! Furthermore, micas and ceramics are often found in tuned circuits where precision is crucial. My recapping article has much more to say about identifying and replacing old caps. Even mica caps can fail, however, and as time goes by, I seem to be finding more and more of them that need replacement.
With the EICO or a comparable tester, I can check suspect micas individually, under their rated operating voltage. Like other vintage test equipment, the B was not manufactured to modern safety standards. To avoid shocks when testing components in an old radio or TV, you should use an isolation transformer and take other common-sense precautions.
It also can check a capacitor under its actual operating voltage, a feature that makes it very handy for restoring vintage tube radios and TVs. After cleaning the controls and replacing a few capacitors, it works like a champ. Below is a photo of the device in action. The "orange drop" type cap is mounted in test terminals at the right. The Range selector is set to the appropriate capacitance range. The green "magic eye" indicator is seen at the upper right.
EICO MODEL 950B MANUAL PDF
Meztisho Skip to main content. Notify me of new comments via email. If you want to join us and get repairing help please sign in or sign up by completing a simple electrical test or write your question to the Message board without registration. This unit was working when I received it.