Precision Electronamic Tube Master 10-12 Tube Tester


	Precision "Tube Master" Series 10 -12 1947 Precision Apparatus Company Inc., 70 - 31 84th. Street Glendale 27, Long Island, New York, USA


	Over the years I've owned a number of dynamic tube testers. Some of them worked better then others but, overall, they all worked fairly well. The one model that has always stood out and has always been a personal favorite of mine is the Precision 10-12. This is a well-designed tube tester that was first introduced in 1947 and was the foundation model for the Precision 10-15, 10-20, 10-22, and the10-54 models. The wooden case, a throwback to the 1930s, looks great on the 10-12 but it wasn't very durable for field usage. Over the years, I've seen many 10-12s whose cases were heavily scratched, stained, chipped, and looking battlefield worn from many field service trips. To find a 10-12 with a case in excellent condition is rare and a good example will usually sell for around $150 on Ebay. One feature makes the Precision 10-12 stand out is the range of tubes that the 10-12 can test. Precision didn't try to outdate the 10-12 by limiting the number of tubes that it could test but, instead, constantly updated the tube data right up into the early 1960s. During the 1960s, Coletronics Service Inc., began manufacturing a number of adapters under the brand names of Precision, Eico and Coletronics which would test later developed tube types such as the 10 pin Decal, the 10 pin Miniature, the five pin and the 7 pin Nuvistor, the Novar and the Compactron. These adapters extended the 10-12s range of tubes, that it could test, and Coletronics published tube data publications for the 10-12 in the form of booklets and supplements on up to 1978. Today the 10-12 can test tubes issued from 1920 on up to 1978, a feat few tube testers can boast. My Precision 10-12 can test more tubes then my Hickok 529C, Hickok 6000 with CA-4 adapter, Precise 111 and my Triplett 3444 mutual conductance tube testers even with all their supplemental data and tube adapters. Only my Hickok AN/USM-118B cardmatic tube tester might have a wider range. I bought my Precision 10-12 from MAI/Prime Parts, a locally owned electronics retail and surplus store located in Indianapolis, Indiana. I bought it for the specific reason of using it as a field tube tester whenever I attend hamfests, antique radio swap meets, etc. I'm confident that any tube I come across, my 10-12 will be able to test it. I buy and sell a lot of tubes and I've found out that I need to use two tube testers, one to help me buy my tubes and one to help me sell my tubes. I use my 10-12 to test tubes that I plan to purchase because I only need to know if those tubes are good or bad, I don't need to fully analyze them. When I sell tubes, which is usually through ebay, I test them either on my Hickok 539C or on my Triplett 3444 mutual conductance tube testers and post the test results on my auctions. I'ts my understanding that perspective tube buyers tend to buy, with more confidence, tubes that have been tested on a high quality, mutual conductance, tube tester rather then on a simpler dynamic tube tester.


	Tube and Rectifier Line Up: 5Y3-GT.....Rectifier


	Power Source: AC...117 Volts


	Dimensions: Height...7-3/4 inches Width...18-3/16 inches Depth...7-3/4 inches


	Operating Instructions for Precision Electronamic Tube Master Series 10-12 & 10-15 This owners manual covers the introduction and summery of features, functions and description of controls, switches, levers, etc.,operating instructions, ballast information, qualitative paper condenser tests, battery testing instructions, service notes, general notes and information, principles of "Electronamic" tube testing and schematic diagram. This manual contains 17 pages, excluding front and back covers. The front cover is copyrighted 1950 and the inner pages are copyrighted 1952. Measures 8.5 x 11 inches.


	Supplementary Tube Chart (Special Tube Classifications) Series 10-12, 10-15, 10-20, 10-22, and 10-54 Tube and Test Masters This supplement covers tubes that are deemed as obsolete, infrequently encountered, and having special / limited applications. Over the years Precision published several versions of this supplement, each with it's own code number that corresponded with the most current roll chart at the time. Example: a supplement with a code of (AB) was meant to be matched up with roll chart MRC-(A2B) or a supplement with a code of (EF) was meant to match up with roll chart MRC-(E2F). Measures 8.5 x 11 inches.


	Supplementary Tube Data Form - MRC (GK) This booklet covers infrequently encountered tubes types, obsolete tube types, tubes manufactured for special or limited applications, Western Electric tubes and forign tubes. Some of the tubes listed require a socket adaptor for testing. This booklet is good for use with Precision models 10-12, 10-15, 10-20, 10-22, and 10-54. Measures 7.5 x 5.5 inches.


	Addendum to MRC Supplement The Addendum is an additional data supplement to be attached to the MRC supplement booklet (GK). It consists of 6 pages, 5 pages covering the additional American and foreign tubes and 1 page consisting of a a list of the American equivalents of foreign tubes that are listed on this and various past supplements. This supplement is dated 3-61. Measures 7.5 x 5.5 inches.


	Manufacturer's Description and Highlighted Features The Series 10-12 and 10-15 "Electronamic Tube-Masters are modern push button, master-lever type operated Vacuum tube and battery testers, incorporating the Electronamic Master tube testing circuit, designed by Precision engineers to indicate the overall performance merit of a vacuum tube in only one direct meter reading. See "PRINCIPLES OF ELECTRONAMIC TUBE TESTING" which details this "Precision feature at rear of this manual. The MASTER ELEMENT LEVER SELECTOR system incorporated in all ELECTRONAMIC "TUBE-MASTERS" provides the ultimate in testing flexibility and positive insurance against NON OBSOLESCENCE. THE PRECISION "TUBE MASTER" incorporates: 12 individual element selection circuits, all latest type tube sockets, master control socket for tubes yet to be designed, and other carefully engineered PRECISION features. These farsighted features guarantee years of successful and trouble-free vacuum tube testing performance. SUMMARY OF FEATURES: 1. A "PRECISION" DESIGNED AND ENGINEERED TESTING CIRCUIT; (the "ELECTRONAMIC" circuit) which instantaneously subjects a tube to wide range operating conditions, simultaneous with the application of individual, predetermined element voltages. 2. ACCOMMODATES ALL MODERN TUBE TYPES AND FILAMENT VOLTAGES .75 to 117 volts, including .75, 10, 18.9, 35, 45, 50, 70, 85 and 117 volts. TESTS NOVAL BUTTON 9 PIN TUBES, SUBMINIATURE TYPES, DOUBLE CAP U.H.F. TYPES, LOKTALS, BANTAM JUNIORS (Miniature Hearing Aid and Pocket Radio Tubes), SINGLE ENDED (T,V, and F.M. Amplifiers) REGULAR OCTALS (MG, G and METALS), SPRAY-SHIELD and GLASS TYPES, MINIATURE 7 PIN TYPES and ACORN TUBES. 3. QUALITATIVE TUBE MERIT readings directly indicated on a single three colored ENGLISH READING SCALE supplemented by a linear scale for tube matching and qualitative comparison purposes. 4. QUALITATIVE DIRECT READING DRY BATTERY TESTS: Tests all popular dry batteries, from 1.5 to 135 volts, under specific predetermined approved loads. 5. DOUBLE WINDOW, BRASS GEAR-OPERATED ROLLER TUBE CHART provides speedy, easy reading tube references. New charts furnished periodically, upon request, as $ no-charge PRECISION SERVICE to all registered owners. 6. DUAL FREE-POINT FILAMENT TERMINAL SELECTION locates terminals of ALL filaments (single, double, center-tapped) regardless of rotating pin position common to many modern FM and television tubes. 7, VISIBLE FILAMENT CONTINUITY TESTS; rapidly performed by the PRECISION NUMBERED PUSH BUTTON SYSTEM; shows up open filaments for all types of tubes regardless of filament base connections. In addition, this PRECISION feature immediately reveals the open section of tapped filaments. 8. MASTER ELEMENT LEVER OPERATED SELECTOR SYSTEM: This highly important PRECISION feature COMPLETELY ELIMINATES ALL POSSIBILITIES OF INFLEXIBILITY due to unusual multiple tube basing terminations of new tubes and tubes yet to be developed. Maximum speed in the use of the lever system is accomplished by the unique fool-proof MASTER LEVER RETURN MECHANISM which allows for instantaneous return of ALL levers to "Normal" position before testing a tube. Individual time-consuming return of each lever is thereby completely eliminated. In addition, simplified tube analysis is made possible by the standard element numbering system employed. 9. SPECIFIC INDIVIDUAL LOADS AND VOLTAGES (control grid, screen, plate, etc.) applied to each respective element of tube under test. 10. METER READS IN PLATE CIRCUIT ONLY. Indications, therefore, are entirely dependent upon control action and condition of ALL intervening elements. 11. OPEN ELEMENTS: Shows up tubes with open elements. The exclusive "ELECTRONAMIC" TUBE MASTER TEST NECESSITATES ALL ELEMENTS INTACT for proper reading. 12. TESTS diodes, triodes, rectifiers, tetrodes, pentodes, multi-purpose tubes, gaseous types such as OY4, OZ3 and OZ4 and remote control gaseous types such as OA4 and 2A4, regardless of varying filaments or other element positions. 13. MULTI-SECTION TUBES: Individual tests for each section of multi-section tubes including visible tests of the fluorescent screen, winking effect on cathode ray indicator tubes and FM/AM alignment ray indicator tubes. No shifting of tubes is necessary to obtain all tests. 14. HOT CATHODE LEAKAGE TEST: Sensitive neon method quickly shows up poor cathode structure in accord with leakage specifications of leading tube manufacturers. 15. DUAL SENSITIVITY HOT INTER-ELEMENT SHORT TESTS made ingeniously simple through the use of PRECISION Automatic Interlocking Push-Buttons, and lens-protected magnified neon lamp. Double sensitivity is made available through the flip of a switch to permit special application tube selection to more rigid standards. 16. NOISE TEST pin jacks incorporated for earphone or amplifier connection. Each element can be separately noise tested through use of free-point Automatic Interlocking PUSH-BUTTON SYSTEM. 17. BALLAST TEST: The regular tube test sockets accommodate all ballast unit tests for open and loose elements and leakage between sections of multi-section ballasts; made possible through the PRECISION rapid-action Push-Button system. 18. PILOT LIGHT TESTS for all miniature screw base and bayonet type lamps. 19. ACCURACY of the tube test circuit is closely maintained by the use of individual calibrating controls, adjusted and sealed at the factory against laboratory standards, and through use of individual, 3% bridge-calibrated wire wound shunts. 20. LARCH EASY-TA-READ D'Arsonval double-jeweled Meter, accurately balanced and factory-calibrated to within 4 2.0 percent. 21. TUBE SELECTION REFERENCES plainly marked on panel in large easy-to-read characters, eliminating memorization or guesswork. 22. PILOT LIGHT ON-OFF INDICATOR. 23. PANEL MOUNTED FUSE EXTRACTOR POST. 24. MICRO-LINE ADJUSTMENT, read directly on meter, provided by use of continuously variable, heavy duty line voltage control. 25. TELEPHONE-CABLED PLASTIC INSULATED WIRING EMPLOYED THROUGHOUT. Critical circuits individually shielded and by-passed for most accurate tests of very high mutual conductance TV and FM amplifiers. 26. PAPER CONDENSER LEAKER TESTS. SENSITIVE NEON METHOD. 27. TEST CIRCUITS COMPLETELY ISOLATED FROM POWER LINE.


	Socket Adapter A-15 Coletronics Service, Inc. 1744 Rockaway Ave., Hewlett, Long Island, New York, USA This socket adapter was designed for the older model Precision and Eico tube testers so that they would be able to test the newer tubes that were on the market during the 1960s and 1970s. This adapter features tube sockets for 10 pin decal, 10 pin miniature, 5 pin Nuvister, 7 pin Nuvistor, Novar, and Compactron tubes. Coletronics manufactured tube adapters under the brand names of Precision, Eico and Coletronics.


	Roll Chart MARC-(F2B) This 16 page booklet is a reprint of the Precision roll chart. It covers those tubes that were considered to be currently still in use, at the time of the booklet's printing, and could be tested on the 10-12 without the aid of any adapters. This booklet was originally offered in spin bound form and it's measurements are 8.5 x 11 inches.


	Tube Data 4-1-74 This 42 page booklet covers all of the American and foreign tubes that require the use of the Coletronics A-15 tube adapter along with additional tubes that could be tested by the tube tester itself. There are a few special European 8 pin miniature tube listings that require the usage of the Coletronics G-118 magnoval adapter to test them. This booklet was meant to be a supplement to the MRC series Roll Chart booklet and was offered in spin bound form with the measurements of 8.5 x 11 inches.


	New Tube Releases for use with MRC 4-1-74 Data Book Coletronics periodically issued 2 page fliers to update the Tube Data 4-1-74 booklet with the latest tubes. I have three such fliers which are dated 7-15-74, 2-15-75, and 11-1-75 respectively. The latest known update is 2-1-78. Measurements are 8.5 x 11 inches.


	Procedure for use of TV PICTURE ADAPTER CABLE-PTA with "PRECISION" TUBE TESTERS SERIES PTA(3-54) This 2 page manual covers the general operating instructions and test values for using the 12 pin Precision CRT Tube Adapter. This manual covers all of the test settings for Precision models 612, 614, 620, 654, 910, 912, 914, 915, 920, 922, 954, 10-12, 10-15, 10-20, 10-22, and 10-54. Measurements are 8.5 x 11 inches.


	Click here to access the most complete compilation of tube data for the Precision 10-12, complements of Chris's Old Radios web site. The four manuals in pdf form seem to be the most complete assembly of Precision 10-12 series tube data that I know of. I think you'll be amaized at just how many tubes can tested on the 10-12 series tube tester.


	Click here to a web page which shows nice collection of photos representing almost all of the various Precision tube testers that were produced.


	Here is an explanation of Precision's tube data chart codes. It was written by Tom "35Z5" and posted by him on the Antique Radios website forum, February 12, 2008. .................................................................................................................................. Letters are used for month and year, so have a double meaning... First letter is month and last is year, number(usually 2) has no significance... Supplements share same code as roll chart, without the number... L & M are not used for determining year... Examples... B2A would be Feb '61... B2C, Feb '53... H2H, Aug '58, etc... A supplement with code HK is Aug '60, as is H2K roll chart... This system was used on all Precision alpha charts. Month......Year JAN -- A --- '61 FEB -- B --- '52 or '62 MAR -- C ---'53 APR -- D ---'54 MAY -- E ---'55 JUN -- F --- '56 JUL -- G --- '57 AUG -- H --- '58 SEP -- J --- '59 OCT -- K -- '60 NOV -- L ------- DEC -- M ------- Known 1952 DRC chart J2B (Sep '52) Known 1962 DRC chart G2B (Jul '62) The '62 charts will have mostly TV types including many 4v tubes such as 4BZ6, 4CB6, 4DT6, etc...


	This web page was last updated: February 24, 2008