I am frequently asked by B&K and Hickok owners to explain how to replace a #83 tube with a solid state version. This question is popular because #83 tubes are scare and expensive. Other benefits are increased reliability (no tube to wear down), less heat generated inside the tester case, and less load on the power transformer. So, if you want to Do-It-Yourself, I will explain how these replacements are made.

I will preface this tutorial with a few caveats: First, this procedure is easier to implement with B&K testers than Hickok testers. Hickok factored in the load that the real #83 tube has on the power transformer, and sometimes you cannot properly set the line without circuit modification. Keep this in mind if you plan to try it with your Hickok — you may be getting in over your head. Hence, substitution may be more effort than it is worth, especially when some Hickok buyers do not want the modification and would have to undo the circuit mods that were made. This leads to the second caveat: not everyone feels that the solid-state substitution works ‘excellent’ in Hickok’s. In fact, some “purists” will not even use a Hickok with a solid-state #83 replacement. They cite the fact that silicon diodes have less voltage drop than a tube rectifier, and feel that the tube test results will not be “pure.”

Personally, I always use a solid-state replacement for B&K testers. For Hickok, I prefer to use a real #83 tube only because circuit modifications are sometimes necessary, which makes going back to a real #83 difficult for the tube tester owner or future buyer. That said, I have no disapproval with using a solid-state #83 in a Hickok, and have found that any tube “test score” differences are trivial. In my opinion, the people who argue about small test score variations are really over-thinking the purpose of testing a tube — the end-result is NOT a test score, but to ascertain whether the tube will work satisfactory in your circuit. Common sense and practicality are important.

Here it goes…

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This article explains how I installed/updated Windows Vista® drivers for a D-Link® DWL-G122 Rev B USB network adapter. This article is informational-only and not intended as advice. Improper driver installation can cause your PC to crash, lockup, or fail to boot. Proceed at your own risk, and no ‘tech support’ is provided.

The article is only relevant to Revision B (known as B1) of this adapter (the DWL-G122 was available in 4 different revisions). The Rev B1 version was very popular because it had native Linux driver support, and also worked well with Windows XP. I have personally used the adapter under Linux (Suse® and Ubuntu®), XP, and Vista®. Unfortunately, D-Link has done a poor job of releasing new drivers for this adapter. To date, D-Link had only released one beta driver package for Vista 32 (Vista X86), and nothing for Vista 64. The Vista 32 beta driver is no longer available for download, either. Luckily, Rev B1 contains a Ralink® RT2500USB chipset, and Ralink has continuously updated the Windows drivers for this adapter. The latest driver package (as of this writing) is dated 11-11-2008, and contains drivers for Vista 32-bit, Vista 64-bit, XP 32/64.

Installing these drivers for D-Link DWL-G122 Rev B1 cannot be done conventionally, but the process is reasonably easy for any seasoned PC technician. To maintain a “clean” PC, I will extract the drivers in a Virtual Machine. This step is optional.

These are the steps that I performed to update the driver for Vista 32 (complete with screenshots):

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This article will discuss repair and calibration of the NRI Professional model 70 tube tester. High voltages are present, repairs should only be attempted by a qualified technician. Copyrighted, all rights reserved.

NRI 70 beautiful hardwood case

Introduction

The high-quality craftsmanship of the NRI Professional model 70 tube tester is readily apparent. It has a beautiful hardwood case (appears to be oak or birch) with finger-joint construction. Eight rubber feet protect your desktop in both the working position and the standup position. Internally, the tester uses a large beefy transformer and quality Pace meter movement. The tester has very small size, measuring only 10.75 x 10.75 x 6.25 inches (27cm x 27cm x 16cm) and weighs a hefty 10.4 lbs (4.7 kg). Most of the weight is due to the large transformer and hardwood case.

The NRI 70 has eight built-in sockets consisting of 4-pin, 5-pin, 6-pin, 7-pin large, 7-pin miniature, octal, loctal, and 9-pin miniature. All sockets use standard wiring (1-to-1, 2-to-2, etc.), and the control lever numbers correspond to their RTMA pin numbers (Lever 1 controls socket pin 1, Lever 2 control socket pin 2, etc.) Read the rest of this entry »

I recently found a February 1940 Jackson tube tester modernization bulletin. This bulletin explains the modernization options available for Jackson tube tester models 627, 627-C, 630, 633, 634, 634-C, 634-D, 635, 637, 680. It also includes the wiring diagram to install a Loctal socket into models 627, 630, 633, 635, 680.

Very interesting bulletin for anyone collecting or repairing vintage Jackson tube testers. I have scanned this 4-page document into a PDF for your benefit.

[ Download the Jackson 1940 Modernization Bulletin PDF ]

To summarize the bulletin:

• Models 634 and 637 sold in 1940 were already modernized at the factory
• Models 634 and 637 sold in their first year (1939) can be easily modernized by the owner (see my article on Jackson 634 for modernization data to install 9-pin miniature socket into these models).
• Models 627, 630, 633, 635, and 680 could be sent back to the Jackson factory and modernized for $5.00 (model 633) or $6.50 (models 627, 630, and 635, which dated from 1938), or $12.50 (model 680). All five of these models had to modernized at the factory because they required installation of a supplementary high-voltage filament transformer, among other parts.
• Models 427-A, 435-A, 535, and 580 were too obsolete to be modernized because “no provision for the high voltage filament types can be made. Miniature types cannot be tested.” Jackson noted that these models were “as much as five years old”, which dates them between 1935 and 1940. Jackson recommended upgrading to the new 1940 models of 634 and 637.

If you are only interested in the Loctal socket modernization wiring diagram, see the accompanying thumbnail photo (click photo to enlarge).

Loctal socket modernization

Going through my parts inventory, I found two nice Sencore Mighty Mite meters.

• Meter for TC-130 Mighty Mite III
• Meter for TC-136 Mighty Mite IV

Each is good condition, tested in-circuit and known to work good.

Price is $74 each plus Priority Mail (less than $5 to most USA destinations).

Email if interested. Again, these are meters – not the entire tester. If you need a replacement meter, this is your opportunity.

Discolored getter flashing (brown or black marks) does not mean that a tube was used. This fiction is believed by both uninformed buyers and seasoned tube jockeys. This myth seems credible because some new tubes have perfect shiny mirror getter flashing; therefore the assumption is that brown or black stains in the getter flashing must indicate a used tube. The myth says that the more brown/black discoloration, the “more used” the tube is. Wrong.

Excerpt from Electronics Magazine

The purpose of the tube getter and flashing is to remove gas inside the tube envelope during manufacture. This discoloration myth can be quickly debunked by reading the article in Electronics magazine, October 1950, entitled “Getter Materials For Electron Tubes”. The article explains that if the getter is vaporized very slowly during the manufacturing process, “the first barium atoms evaporated will absorb the gas present so that the remaining getter is deposited in a very high vacuum, exhibiting a shiny mirror.” If the getter was flashed very rapidly during manufacturing, then “the getter mirror will be discolored due to the dispersion of the barium.” The article then explains that the discoloration “does not mean that the getter is contaminated, but merely that the deposit is finely divided and therefore absorbs light.”

Several photos of NOS tubes below demonstrate this myth.  Likewise, I provide photos to demonstrate how the flashing looks when a tube is actually used. Let us proceed…

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(Copyrighted, all rights reserved.)  This article discusses repair and calibration information for a number of vintage capacitor testers that all use the same fundamental test circuit.   The article currently covers the EICO 950-series, PACO C-20, Knight KG-670, Heathkit C-2 and C-3, etc.  (More models will be added on an ongoing basis as I find the time. ) All of these models are almost identical in functionality and circuitry.

These units are known as a Resistance-Capacitance Bridge, an R/C tester, but are most commonly used as a capacitor tester. Extreme caution must be followed with any vintage capacitor tester because very high voltages are present during repair and while operating. They should only be used by knowledgeable technicians.

EICO 950A

PACO C-20 tester

Knight KG-670

Heathkit C-3 (dark color scheme)

Heathkit C-3 (light color scheme)

These models use a balanced bridge that measures capacitance from 10mmf up to 5000mf and resistance from 0.5 Ω up to 500-MΩ. During component value testing, the magic eye tube serves as the null-indicator. When the bridge is far from balanced, the target area of the magic eye tube glows completely closed green, and in fact overlaps. As the pointer dial approaches balance point, first the overlapping disappears and eventually the entire target area of the eye tube is completely open (dark). The bridge is balanced when the maximum dark area is indicated, and you can then read the value of your component on the faceplate scale.

Most models use the magic eye tube for both Leakage testing and component value testing.  With the Eico 950A, leakage of Paper/Mica caps is indicated by the #1629 magic eye tube, but electrolytic leakage is indicated by the Neon bulb.

Any technician who repairs vintage tube equipment (such as tube amps, antique radios, vintage jukeboxes) will find that a quality capacitor tester is a useful test instrument.

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This article discusses repair and calibration of the older tube-based Sencore Mighty Mite tube testers that use the 12AU7A tube inside, such as model TC130, TC136, and TC142. I will also discuss the most common problem that causes “faulty” Grid Leakage detection. High voltages are present, repairs should only be attempted by a qualified technician. Copyrighted, all rights reserved.

TC130 Mighty Mite

TC130 Mighty Mite case

Introduction

Sencore Mighty Mite testers employ a Cathode Emission test circuit, with short detection and industry-best 100-Megohm leakage detection. The leakage detection circuitry is really the reason that every technician should own a Mighty Mite as part of his/her tube testing arsenal.

All Mighty Mites are designed to test newer tubes. You will not find any antique sockets (such as 4-pin, 5-pin, 6-pin, 8-pin large, etc.) Socket configuration consists of Octal, 7-pin miniature, 9-pin miniature, Nuvistor, novar, Loctal, and Compactron.

Each model has a roman numeral designation: TC130 = Mighty Mite III. TC136 = Mighty Mite IV. TC142 = Mighty Mite V. There are no practical differences among them.

The older Sencore Mighty Mite tube testers have tube circuitry inside, whereas newer Mighty Mites (such as TC154 and TC162) are transistorized. Otherwise, their functionality is comparable. Some units have a CRT picture tube wire harness with socket attached. This harness is very bulky, so common sense would suggest to remove it. It serves no practical purpose and only clutters up the case. Some models have a few pin straighteners on the front panel.

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Early this year I found this vintage Colin B. Kennedy Corp radio. Model 62LS lowboy console with model 54A shortwave unit. I recently finished rebuilding this radio. It is available for purchase (local pickup preferred, but crating and shipping can be arranged but will be quite expensive). It would make a beautiful addition to any old home or turn-of-the-century mansion. This beautiful antique radio is more than a radio — it is a beautiful piece of furniture as well. Colin B. Kennedy Corp marketed themselves as the “The Royalty of Radio”, and the high quality craftsmanship is readily apparent.

Colin B. Kennedy Corp model 62LS lowboy console radio with model 54A shortwave unit.

This is actually the second Kennedy console radio in my collection.

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This article will discuss repair and calibration of the Heathkit TC-2 tube checker. High voltages are present, repairs should only be attempted by a qualified technician. Copyrighted, all rights reserved.

A new SS9 socket saver has also been installed, and new Top Cap assembly has been installed.

(Heathkit TC-2 testing Arcturus Blue #127 detector tube)

Introduction

The Heathkit TC-2 was a self-assembled tube tester kit offered by the Heath Company. It was popular among servicemen because they could buy a “name-brand” tester and save money by building the kit themselves. Since the TC-2 is the same test circuit as the Eico 625, Triplett 3413, and Knight 600 series, which was the subject of my last repair-and-calibration article here on my website, I will not reiterate what was discussed in that article.  Everything discussed in the Knight article is pertinent to the TC2.  Likewise, if you need a manual, schematic, or test data for TC2, the Knight 600 documentation will serve you fine (assuming you can mentally adjust for the trivial naming differences).  Hence, this article will focus on the very minor differences between the TC-2 and the Knight 600. (Click HERE to read the previous article.)

Differences

The following minor differences exist between these models, and they need to be addressed when rebuilding and calibrating the TC-2:

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