This article discusses repair and my calibration procedure of the Precision model 10-12  tube tester.   Serious electrical voltages are present, repairs should only be attempted by a qualified technician. Copyrighted by Bob Putnak, all rights reserved.

Introduction

6 Paco 10-series tube testers from my collection

The Precision Apparatus Company (commonly known as PACO) manufactured some very high quality test equipment.  Among their offerings are the “10-series” of tube testers, such as model 10-12, 10-15, 10-40, 10-54.  The tube test method is the same in all, and the test data is interchangeable.

I have been collecting since 1990, and in my experience model 10-12 was the most popular unit.  I have found many 10-12 over the past 19 years, and serviced many more.    I have only found one different model for my own collection, a model 10-40 that you see in the photo.

Precision Apparatus 10-12 tube tester with custom TubeSound plate current meter upgrade

It is easy to see why model 10-12 was most popular.  Four adjectives come to mind: Attractive, durable, consistent, quality.  Attractive — it has a beautiful furniture-grade hardwood case.  Durable — the entire unit is built-like-a-tank.  Consistent — I have always found these units to produce repeatable test results, year-after-year.  Quality — consistent test results from the “Electronamic” test method add up to a quality piece of test equipment.



Paco A-15 socket adapter

Paco G-140 Socket Adapter

The 10-series is also popular today because it will test a very large variety of tubes.  Model 10-12 has built-in sockets for antique tubes 4-pin, 5-pin, 6-pin, 7-pin large, and acorn.  It also has sockets for octal, loctal, 7-pin miniature, and 9-pin miniature.  Socket adapters (models A-15 and G-140) were later available, which adds the ability to test 10-pin miniature, nuvistor (5 & 7 pin), novar, and compactron tubes.  Therefore, if you have the socket adapter panel, you can effectively cover the entire range of tubes from antique 4-pin through modern 12-pin compactron.

The tester also has a NOISE JACK for connecting a set of headphones to audibly evaluate “tube noise.”

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This article discusses repair and calibration of the Signal Corp I-177  tube tester.   Serious electrical voltages are present, repairs should only be attempted by a qualified technician. Copyrighted by Bob Putnak, all rights reserved.

Introduction

Signal Corp I-177 tube tester

Model I-177 is a very old US Military dynamic mutual conductance tube tester that was used during World War II years.  The War Department Technical Manual is dated August 1944, and the tester calibrated in this article is dated April 1945. The unit is extremely well-built.  Due to its age and high signal voltage, the tester is only suited to test the “antique tubes” and military tubes of its era, and does not even have a 9-pin miniature socket. Although a socket adapter panel does exist to accommodate testing “newer” tubes, the tester is not suited for that task and can easily damage small signal tubes.  That said, the I-177 does an excellent job of testing the tubes of its era.


Repair

The fundamentals for starting the I-177 project: all knobs and the meter itself are indexed at zero, check all resistors and potentiometers for accuracy and replace where necessary , replace the 0.1 mfd capacitor, clean all sockets/switches/leaf-switches/pots/rheostat with Deoxit to the extent possible. I would specifically note that the I-177 has 7 carbon resistors.  Expect that most (if not all) of these carbon resistors will have increased in resistance and will need replaced.  The remaining resistors are either wirewound or precision types, and while they should be tested, it is unlikely that any would be defective.  Inspect all wiring (AC power cord, and also each wire connection at every tube socket pin).  Remove both bulbs (#81 fuse bulb and neon shorts lamp), clean bulb connections and sockets, reinstall.  The #81 fuse bulb must be only a #81 bulb (no substitutes).

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BK 607 tube tester

B&K 607 case

This article discusses the solid-state B&K 607 / 667  tube testers.  Both models use the same tube setup data book, and therefore both models are functionally equivalent.    Model 607 will be example shown in this article.  Electrical voltages are present, repairs should only be attempted by a qualified technician. Copyrighted, all rights reserved.

This series was B&K’s clone of the Sencore Mighty Mite TC162.  While the circuits are not 100% identical, they are close enough to be considered functionally identical.  The B&K 607 weighs slightly less than 6-lbs (without setup book or manual), and size dimensions are: 34 cm L x 24.5 cm W x 11 cm D.  The case folds open and easily accommodates a full size 8.5 x 11 inch setup chart and service manual as shown in the photo above.

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HP Officejet R-series

As a fan of vintage tube equipment, it should come as no surprise that I prefer older quality computer equipment.  In this article, I explain how to repair “Scanner System Failure” problems in a vintage HP Officejet R-series multifunction scanner-printer.  Model R40xi is shown in the photos, but all models (R40, R40xi, R60, R60xi, R80, R80xi) repair the same.  In fact, many similar HP multifunction units of this era are repaired in similar manner.

First, let me explain why I feel that these vintage HP units are worth repairing.  Why fix an “old parallel-port printer” when new models are so cheap?  Like most things in life, you really do get what you pay for, and if HP paid me to take their new models (with the assumption that I actually had to use them), I would not be interested.

During the Lew Platt years, HP was making top quality products.  This period of quality was from the early 1990s (Laserjet 4-series and beyond) through the Officejet R-series of 1999.   The hardware during this time was built-like-a-tank, and when compared to today, the ink supplies were reasonable (although they certainly seemed expensive at the time).

Let us look at the economics: Officejet R-series uses a #45 cartridge, holds 42-mL ink, retail cost $30.  This HP45 can be purchased for $5 on eBay. Modern HP cartridges hold as little as 5-mL ink and cost $15 — which is 4.2 times more expensive using retail price comparisons.  If you consider surplus #45 cartridge prices as your comparison, the cost to operate a new HP printer can be  42-times more expensive.  And if you are an environmentalist (or anyone who hates frivolous waste), ask yourself whether it is environmentally responsible for HP to manufacture an ink cartridge that only holds 5-mL or 10-mL? Certainly not, and those puny cartridges are only sold to pretend that the new cartridge price is cheap, when in fact it holds 4-to-8 times less ink.   That is an insult to your intelligence and an affront to the environment.

In another example, a modern HP toner cartridge (for a current model) costs $99 retail with approx 2,000 page yield.  Surplus HP toner cartridges for the old 4-series, 5-series, or 6-series can be purchased for approx $20-$30 on eBay, and have 3,000+ page yields.  Vintage Laserjets have been known to be run strong with 500,000 page cycles.  Any chance you will get even 50,000 page cycles with a modern unit? Good luck with that.  And how many Nag messages from the new drivers to “buy more ink” would you click on during that time?  Well — no nag messages with old HP units!

So when you analyze the situation, the answer is obvious why I fix these old HP units.  (1) High build quality of the hardware, (2) low cost of use (ie – cheap ink), (3) OS drivers that respect you as a person, without bloat or nag screens to harass extra ink purchases, (4) ink that does not “expire” because some Corporate Executive wanted to sell more ink to pay for his/her 7-or-8 figure CEO salary + stock options + benefits + perks + Golden Parachute retirement package.

Let us compare the “new” models.  By ‘new’ models, I consider any model released in the Carly Fiorina era and beyond to be ‘new’.  The only benefits that I can see in the new models are USB connection (which is easier for most users but otherwise adds no functionality) and much better color printing.  Since I have no problem with parallel ports and only print black-and-white, those issues are not important to me. Otherwise, it is my opinion that the quality of the new hardware is much lower than the older models, the cost of consumables (ink/toner) is outrageously expensive, the computer drivers are bloated and filled with nag messages that harass you to “buy more ink”, and some models “expire” the ink cartridges based upon a random date.   If you feel respected as a customer with that experience, more power to you.   Personally, I am not interested in participating.

With that explanation, let us move on to the repair.  As always, repairs are only suited for experienced electronic technicians with suitable training.  Also, it is useful to take a video of your repair project so that you can reexamine your work if you get stuck during reassembly.

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©2009, All rights reserved.

The article will discuss a cheap and easy way to test panel meters. The meter in your tube tester is an example of a panel meter. Occasionally you see flaky meter operation and suspect that the panel meter may be defective.  Most techs know that it may not be safe to test a panel meter by placing an ohmmeter across its terminals — this attempt can ruin the panel meter (depending on the ohmmeter used) and will not reveal all of the panel meter specs anyway.

Most panel meters in vintage equipment (such as tube testers or capacitor testers) will be milliammeters or microammeters.  The good news is that these panel meters can be tested, although extreme caution must be exercised.  One mistake and you can easily ruin the meter, so “do not try this at home” until you have practiced with a large variety of junk meters and have sufficient experience and confidence in your skills. Even then, “triple check” everything before you proceed.

Simpson 2600 Calibrator

Many people think that you need to have expensive equipment to test panel meters.  It would be nice to own a Simpson 2600 Laboratory-grade Calibrator (which cost $1,620 in 1965 and weighs 132-lbs).  But you can make do with the following basic equipment: a variable power supply, a quality resistor decade box, a quality multimeter with mA and µA capability, and another quality digital multimeter that will accurately test millivolts.  Likewise, you need an understanding of what you are trying to accomplish.   Keep in mind that Ohm’s Law teaches that voltage, resistance, and current are all interrelated, therefore a panel meter that has its faceplate scale in “volts” CAN be tested as an ammeter.

In the following discussion, I will demonstrate testing a panel meter.  You will (1) determine the full-scale spec of the meter (using the printed scale as your reference for full scale), (2) evaluate whether the meter action is smooth and accurate across its entire range, and (3) determine the internal resistance of the meter.

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A common (and totally random) problem with GM vehicles that have the Passlock / Passlock II anti-theft system is that the vehicle will suddenly refuse to start.  The problem is a poorly designed GM Passlock anti-theft system that erroneously enters anti-theft mode and disables the fuel injectors. GM should be forced to recall this Passlock system — it is simply unacceptable to strand motorists because of an incompetent anti-theft system.

The vehicle in this example is a 2002 Chevy Malibu, but this Passlock system was employed in many GM models.  Thousands of motorists have been stranded and left helpless by these GM vehicles that refuse to start for no apparent reason.  The owner of this Malibu was stranded three times over the past two years, incurred 2 towing bills to a Chevy dealership, two “repair” bills from the incompetent Chevy dealer who obviously failed to solve the problem.  Now she was stranded for a 3rd time.  This time she called me.

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This article will discuss Mercury tube testers. The Mercury Electronics Corporation of Mineola NY produced a number of tube testers in the 1960s.  All models are small, portable, and lightweight.  Popular models include 990, 1000 / 2000, 1100, 1100A, 1100C, 1101.  Models and comments will be added as I find time.   Electrical voltages are present; repairs should only be attempted by a qualified technician.

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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 most 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.  This problem is particularly true for the “red-case” Hickok’s.

That said, I have no disapproval with using a solid-state #83 in a Hickok model that lends itself to working well, 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 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

Built by Precision Apparatus Co for NRI, 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 (Precision Apparatus) 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