Lafayette TE-50 Tube Tester Operating Instructions
Contents
1. D O H A D O O O E PEIE EIEIEITIE gt OOOO ooo OHO Oni Oni Oni 2 4 o ETE TUBE 4 5 7 8 9 ye gt TOF cat TC Q 0 erent SCHEMATIC DIAGRAM Waranty The Lafayette equipment you have just purchased has been expertly designed and was care fully tested and inspected before being shipped to you If properly installed and operated in accordance with the instructions furnished it should provide you with the finest results A All parts contained in Lafayette equipment are warranted to be free from defect for 90 days from date of original purchase Exchange replacement or repair will be made to any part of the equipment which proves to be defective within this period without charge to the owner for parts or labor incurred in such repair B After 90 day period is past we can supply any replacement part for Lafayette equip ment at a nominal charge for parts and labor This warranty shall not apply unless the equipment or part is returned for our examination with all transportation charges prepaid to the address below nor shall it apply to equip ment which has been subjected to misuse accident or neglect This registration card must be filled out and mailed within ten days of purchase to place this warranty into effect LAFAYETTE RADIO 7 111 JERICHO TURNPIKE SYOSSET L 1 N Y Printed in Japan2. The load control and or 470 ohm resistor may have been burnt out See note following Note The load control must be set according to the tube chart for quality tests It should never be turned to zero during the quality test otherwise damage to the control and tube will result Tester will not indicate short or filament continuity Trouble is usually caused by an open circuit 0 01 pfd capacitor or defective neon lamp Tube tests good in the tester but will not operate satisfactorily in the radio or TV receiver CAUSE An emission test is only one type of test that can be applied to a tube It indicates the amount of electrons that leave the cathode of the tube Although this test will indicate the condition of the tube in most cases certain other tests may be necessary to fully evaluate a tube s condition Amplification factor mutual conductance and transconductance are some of the factors that may cause a tube to act erratically An emis ion test will not show up these tube characteristics SYMPTOM The meter does not read to full scale on any tube Even new tubes do not bring the meter to full scale CAUSE This condition is normal The circuit has been designed so that a normal good tube will never read full scale on the meter FIL VOLTS amp AC IND NE 2 AWW 100KQ 2 2KQ UAK ANP 4700 PINT PIN2 PIN3 PIN4 PINS PIN6 PIN7 PINS PIN9 PINIO PINI PINI2 TC
3. LAFAYETTE TUBE TESTER MODEL TE 50 OPERATING INSTRUCTIONS LAFAYETTE RADIO ELECTRONICS CORPORATION Printed in Japan ER eee The Lafayette Model TE 50 is a modern and compact Tube Tester designed to provide speedy yet efficient operation The Model TE 50 will test tube types used in Radio Hi Fi Monochrome color TV etc for quality of emission and inter electrode shorts Sockets and circuits have been provided for testing the new Noval and Sub Minar types in addition to the Octal Loctal and 7 pin miniature types as well as new 9 and 12 pin Compactron tubes and Nuvistor tubes The socket for Noval can take a 10 pin tube of this type Before attempting to use the tester we suggest you read the operating instructions contained in this manual in order to acquire a proper understanding of how this unit works DESCRIPTION OF SWITCHES AND CONTROLS TUBE SOCKETS Eight sockets are provided Octal Loctal 9 pin Noval 7 pin miniature 8 pin sub minar 9 and 12 pin Compactron and Nuvistor tubes Be sure to insert the tube in the correct socket in all cases TOP CAP LEAD This lead supplied as the integral part of TE 50 is provided for connection to tubes having a top cap and for insertion into the jack marked T C If the tube under test does not have a top cap take care not to allow the lead to touch any metal part of the tester ELEMENTAL SLIDE SWITCHES These switches are used to connect the various tube elements to th
4. d N positions as specified on the tube chart All other elemental switches should be set to the K position 6 Insert the tube into its correct socket Allow at least 30 seconds for it to warm up 7 With the exception of those previously set to F and N move each elemental slide switch one at a time to the P position Tap the tube and observe the LEAK IND lamp moving each switch to the P position and then returning it to K i WARNING AT NO TIME MUST THERE BE MORE THAN ONE SWITCH IN THE P POSITION A steady glow in the Leakage Indicator lamp when any one of the switches is set to P indicates a short A slight glow may be disregarded when testing certain audio tubes such as the 6L6 50L6 etc These tubes have a high inherent leakage This however does not affect their normal operation In all other cases no glow is desirable but a slight glow may be considered passable Note A steady glow on any of the elements listed in the filament continuity column does not indicate a shorted tube This indicates filament continuity 8 Remove the tube from the socket HOW TO TEST A TUBE FOR QUALITY Do not conduct this test until you have checked the tube for shorts and leakage If you have already done so and the tube appears normal with respect to shorts or leakage proceed as indicated below Do not change any of the control settings previously made for the tube under test unless instruc
5. der test The switch should always be set before inserting a tube Never change the setting after a tube is inserted POWER SWITCH This switch turns the unit on and additionally serves to adjust it to various AC line voltages The HI position is for line voltages between 115 and 125 volts The LO position is for line voltages between 105 and 115 volts When in doubt as to the voltage of an AC power line set switch to HI Like all emission type testers the Model TE 55 provides a means of making two basic tests 1 Tests for shorts and leakages 2 Test for quality of emission Tests for shorts and leakages should be carried out first and then followed by the quality test It is advisable to do so because if a shorted tube were tested for quality first it could cause serious damage to the meter Proceeding with the tests in the order recommended will prevent this happening HOW TO TEST A TUBE FOR SHORTS OR LEAKAGES 1 Insert line cord into AC power outlet If the AC line voltage is between 115 and 125 volts set POWER switch to Hi if between 105 and 115 volts set to Lo When in doubt set to Hi Note If an asterisk appears before a tube listing in the chart always set the switch to the Lo position Set the Leakage Quality switch to LEAK 4 Set the FIL VOLTS switch to the position specified on the tube chart for the tube to be tested Set the appropriate elemental slide switches to the F an
6. eir respective test circuits The switches are numbered from 1 to 12 and correspond with the RMA basing of the tube The letters F N P and K provide the following functions F Filament When any element is switched to this position the voltage selected by the filament voltage switch is applied between this element and all other elements left in the K position N Neutral When any element is switched to this position it is isolated from all other elements in the tube It can be used for example to isolate a tapped filament from all other elements during a tube test e gee P Plate This position inserts the meter into the circuit during quality tests and the indicator lamp during the short test of an element More than one element should never be placed in the P position K Cathode Switches not used in the actual test are left in this position and act as part of the cathode or return circuit LEAKAGE QUALITY SWITCH This switch determines the type of test performed by the TE 50 When placed in the QUAL position the quality or emission of the tube under test is indicated on the meter The SPEC position applies a higher test voltage to the tube and is used only when the letter S appears after an element in the P column of the chart In the LEAK position inter element shorts and leakage are indicated by the leakage indicator lamp LEAKAGE INDICATOR Used in conjunction with the leakage quality switch it
7. lows TUBE FIL VOLTS F N P LOAD FIL CONT 6CB6 D 3 1 30 3 4 Set the Leakage Quality switch to LEAK Set FIL VOLTS to D Set LOAD control to 30 Set the 3 elemental switch to F All other should be set to K Insert the tube into the 7 pin socket which is the correct one for the 6CB6 Allow at least 30 seconds for the tube to warm up onan 9 One at a time move each elemental slide switch except number 3 to the P position Tap the tube and observe the leakage indicator lamp A steady glow when the switches are moved to P indicates a short Be sure to return each switch to K as you proceed NOW TEST FOR QUALITY 1 Set Leakage Quality switch to QUAL 2 With the 3 elemental slide switch at F set the 1 switch to P Make sure all other switches are at K 3 Read the quality of the tube directly on the Replace Good portion of the scale Note Tubes listed in the tube chart more than once are multi purpose tubes and are equivalent to several tubes in a single glass envelope It is necessary therefore to test these tubes according to each listing just as you would several different tubes IN CASE OF DIFFICULTY As a helpful guide to the user of this tube tester we have compiled a list of problems commonly encountered during the use and operation of the unit SYMPTOM The Tube Tester burns out the filaments on some tubes CAUSE The knob on the filament s
8. provides a steady glow when an inter element short or leakage is present in a tube A flash of the indicator when switches are moved should be disregarded This is due to wiring and tube inter element capacity METER The quality emission of the tube under test is indicated on the meter There are three calibrated portions of the scale 1 The Replace Good portion provides a broad indication of quality The green good section indicates sufficient emission to assure quality performance the white section denotes border line emission and the red replace section indicates below normal emission 2 The 0 100 calibration provides a more precise means of determining quality of emission and may be used to compare the relative emission of similar tubes 3 Tbe HV Diodes OK calibration is for use in testing diodes only Many diodes cspecially high voltage rectifiers have a high internal resistance which reduces the emission reading As a result tubes of this type may produce an emission reading of as low as 20 and still be per a fectly good Examples of the types of diodes falling into this category are the 1AX2 1B3 1V2 1X2 1Z2 2V2 2V3 and 3A3 LOAD CONTROL This control determines the amount of loading placed upon the tube under test The smaller the number the greater the current drawn from the tube under test FILAMENT VOLTAGE SELECTOR This selects the correct operating potential for the filament of the tube un
9. ted to do so 1 Set the Leakage Quality switch to QUAL If the letter S appears after the element listed in the P column set switch to SPEC Disregard the glow of the indicator lamp in this position Set the elemental slide switches to the F N and P positions as specified on the tube chart All other elemental switches should be set to the K position Set the LOAD control to the position specified on the tube chart Insert the tube into its correct socket Allow at least 30 seconds for it to warm up Read the quality of the tube directly on the meter If the meter pointer does not move at all the trouble may be due to an open filament To verify make the checks described in the following section HOW TO TEST FOR FILAMENT CONTINUITY Proceed as in the test for shorts or leakages Set either of the elemental slide switches listed in the filament continuity column to P with the other at K the indicator lamp will glow if the filament is good No glow indicates an open filament EXAMPLE OF A TYPICAL TUBE TEST TYPE 6CB6 FIRST TEST FOR SHORTS AND LEAKAGE l 2 Insert line cord into AC outlet Place the POWER switch to the appropriate setting depending on the AC line voltage If in doubt use Hi Since no asterisk appears with this tube listing the switch may be left in the Hi position if necessary Yocate data for 6CB6 on tube chart This reads as fol
10. witch may have become loose and shifted position thus applying incorrect voltage to filaments of tube under test Make sure the fully counter clockwise setting of the switch is aligned with letter A SYMPTOM The tester tests 12 volt tubes as bad even though they are known to be good CAUSE SYMPTOM CAUSE SYMPTOM CAUSE SYMPTOM CAUSE SYMPTOM CAUSE SYMPTOM CAUSE SYMPTOM Same as previous symptom Knob on filament switch may have shifted Tester indicates short on good tubes when any one of the elemental switches is moved to the P position A shorted 0 01 fd capacitor will cause a false short indication on all positions Tester indicates short on some tubes but not on others All tubes are known to be good Due to incorrect operation The element listed in the P column of the tube chart is placed in the P position for quality tests only It should te returned to the K position before proceeding with the short test Never place more than one switch in the P position at any one time Tester indicates short when one of the switches is set to P This occurs on all tubes tested Tubes are not shorted The elemental switch which causes the indicator to light is the one listed under the Fil Cont column of the tube chart This indicates filament continuity and not a short Tester shows all tubes to be good even though they are weak
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