Methods of Valve Testing

OSRAM VALVES

Type Range
ValveFil.Selector Degree
B212.0616.5
B212.07 (2nd P.)16.5
DHD12.58TA
do.do.1DAMax
do.do.5DAMax
DHX12.516
DL12.51
DPT12.518.75
DS12.518.5
DSB12.516.75
GU14.0111
H22.018
H2102.0121
HL22.018.25
HL2102.0111
L212.019.5
L2102.0116
LP22.01
LS6A5.01
MH44.015.5
MH414.014.25
MH4/K/M4.016.5
MHD44.08TA6.5
do.do.1DAMax
do.do.5DAMax
MHL44.017.5
MPT44.015.75
MPT44.06 (7 Pin)7.5
MPT4/K4.017.5
MS44.017.5
MS4B4.01
MSP44.06
MU124.016.5
do.do.2 (2nd P.)6.5
MU144.016.5
do.do.2 (2nd P.)6.5
MS4B/K/M4.016.5
P22.019.25
P2152.0113.5
PT22.018.75
PT42.01
PT164.01
PT254.01
PX44.018.75
PX254.01
S212.0111.5
S222.017
S232.0112
U104.0111
do.do.2 (2nd P.)11
U124.0110
do.do.2 (2nd P.)10
U144.0111
do.do.2 (2nd P.)11
VDS12.5113.5
VDSB12.51
VMP44.06 / Type Range
ValveFil. Selector Degree
VMS44.01
VMS4B4.01
VMS4/K/M4.017.5
VP212.06
VS212.018.25
TA – Triode Anode
DA – Diode Anode

METHODS OF VALVE TESTING

Just what constitutes the best method of testing a valve to determine its general condition, has been the subject of much discussion among radio engineers.

Opinions at one time were divided between the relative efficiency of the four existing methods viz: The true mutual conductance,the power output, the grid shift and the emission test.

An avalanche of new valves settled the controversy by bringing the emission tester into general favor as a commercial valve tester because, it was the only system which could be adapted to incorporate all the following points.

1. Ability to cope with the hundreds of existing valves as well as future releases.

2. Simplicity and quickness of operation.

3. Reasonably low selling prices.

4. Practical accuracy.

The true mutual conductance tester, whilst the most accurate, is purely a laboratory instrument requiring as many controls and meters as there are elements in a valve. Therefore it can be regarded as impracticable for commercial purposes.

The limitation of the so-called "grid shift" and power output systems, combined with the fact that a well designed emission tester may be the more accurate, has brought the latter into universal use. It will be realised that the only thing likely to happen to a radio valve in service, (apart from leakage between elements) is a depreciation of the emitting qualities of the cathode element. So why not test a tube for its emission current?

This has been confirmed by our own and overseas laboratory comparisons.

When the emission type valve test was first developed, the mistake was made of applying a high voltage to the valve through a voltage dropping resistor. Consequently the voltage applied to the valve (tested as a diode) depended on the current drain. This meant that a poor valve which had a low emission, was tested at a higher potential than a good one and that true differences of merit could not be arrived at. Then again there arose the danger of harming a poorish valve through excessive voltage being applied to the grid and injuring the cathode coating.

In the "Palec" valve tester, a constant low voltage is applied and the current drain limited to well below saturation point.

This low voltage is not sufficient to ionize the gas if present in a valve and produce extra emission. Consequently the “Palec” valve tester is a true emission tester and shows the true condition of the cathode independent of whether gas is present or not.

With regard to a gas test, it must be remembered that the percentage of gassy valves is low among new valves, as the manufacturers are usually careful that no such valves leave the factory.

The percentage of valves which become gassy with use is extremely low, less than ¼ % actually.

Before a valve becomes gassy, it must usually, be seriously overloaded. This overloading causes a drop in the emission capabilities of the cathode. This condition is detected by our tester.

Thus, the tester does, in almost every case, class a gassy tube as poor on account of it usually showing poor emission under the test applied.

A.C MODEL

INSTRUCTIONS FOR USE

The operation of completely testing a valve on the PATON “PALEC” A.C. Model Valve Tester should be carried out in the following order:-

No. 1-ADJUST LINE VOLTAGE.

Switch on power and press red button atleft bottom marked “LINE CHECK” The Meter Needle should swing right over the designated line on Dial. Should the needle be above or below this point, adjust to same by means of the top left rotary switch, marked “LINE ADJUST.” It is important to constantly check the line voltage. This test is made before plugging in valve.

No. 2 - Select correct filament voltage as shown on chart.

No. 3 - Plug in valve.

No. 4 - Test for inter-element shorts and leaks: While the valve is heating, throw “ELEMENT SHORTS” toggle switch to “ON” and rotate the selector switch from point round the full semi-circle.

A shorted element or leakage even as high as 500,000 Ohms will cause the Neon electrodes to give off a distinct and definite glow. (This can he demonstrated by connecting a half meg pig tail resistor between two of the valve pins and noting the intensity of this glow). When the valve is fully heated a very faint glimmer may be noticed when on the Cathode position, but this could denote a resistance leakage of some millions of Ohms and can safely be disregarded.

If the valve passes the above test proceed as follows:

No. 5 - ThrowElement Shorts toggle to “OFF”

No. 6 - Turn Selector Switch to the point as shown on chart.

No. 7 - Adjust Range Degree control also as per chart.

No. 8 - Press green button marked “MERIT TEST” and the meter will show directly the condition of the valve.

In the cases of Cathode type Valves allow plenty of time for the Valve to become fully heated. This will he shown when the Meter needle stops creeping and remains stationary.

N B.-The Meter Dial is calibrated to show the percentage efficiency of a Valve.

A variation of 10% or so may he noted in new Valves. This is quite normal.

DIODEPLATES - A comparative test can he made on the Diode Plates by turning Range Control to Maximum positi6n (unless otherwise stated) and Selector Switch to the respective point shown on chart, marked DA.

The readings of both plates should be noted between the forty per cent and sixty per cent margin on Meter Dial, and should be approximately the same.

To Identify the Shorting or Leaking Elements.

The points of the Selector Switch correspond to the various elements of a Valve and are numbered according to 1935 standard practice, with the exception that the valve cap is numbered 8.

No.2 is the plate position of all American Valves, while No. 5 is the general Cathode position.

Filament pins 3 and 4 are not represented on switch, being unnecessary. A glow at any one point denotes a short to filament, while a glow at any two points shows the short to be between the two elements indicated.

MULLARD’S VALVES

Type Range
ValveFil. Selector Degree
ACO444.011 12.75
ACO644.0114.5
ACI044.0110
D0264.0111
DU24.0110.0
do.do.8 (2nd P.)10
DW34.01
do.do.2 (2nd P.)
DW44.0110.0
do.do.2 (2nd P.)
DW157.519.5
DW157.52 (2nd P.)9.5
FC44.066.5
IW34.01
do.do.2 (2nd P.)
MM4V4.016.5
Pen. 4VA4.066.5
PM1A2.0118.5
PM1DG2.0118
PM1HF2.01
PM1HL2.0117.5
PM1LF2.01
PM122.01
PM12A2.018.25
PM12M2.018.5
PM12V2.0114.25
PM144.0118.5
PM166.3120.0
PM22.01
PM2A2.018.25
PM2B2.018.0
do.do.68.0
PM2DX2.0113.0
PM34.0112
PM44.0114.5
PM4DX4.019.5
PM5V6.01
PM5X6.0115
PM66.0112.5
PM22A2.018
PM244.0112.5
PM24A4.0110.5
PM24B4.018.25
PM24M4.0110.5
PM266.0111.5
PM2022.0110.5
PM2522.21
PM2566.01
PM2BA2.019.5
do.do.6 (2nd P.)9.5
SP22.067
SP44.065.5
S4V4.0112.5
S4VA4.014.5
S4VB4.01
TDD22.08TA12.25
do.2.01DAMax / Type Range
ValveFil. Selector Degree
do.do.6DAMax
TDD44.08TA9
do.do.5DA11
do.do.7DA11
VM4V4.06
VP22.066.25
VP44.065.5
104V4.016.5
164V4.019.25
244V4.015.75
354V4.016
904V4.015.5
TA – Triode Anode
DA – Diode Anode

PHILIPS’ VALVES

Type Range
ValveFil. Selector Degree
A2092.0117
A4094.0114.5
A4154.0110.5
A4254.0112.75
A4354.01
A4424.0118.5
A6095.0113.5

A6155.0110.25

A6305.0112

A6355.0120.5

A6425.0113.25

ABC14.0v8TA11

do.do.7DAMax

do.do.6DAMax

AC24.0v86.5

AF24.0v65.5

AF34.0v87.5

AF74.0v87.5

AK14.066

AK24.077.5

AL24.088.0

AL34.075.25

AZ34.026.0

do.do.6 (2nd P.)6.0

B2172.0117

B2402.018

do.do.6 (2nd P.)8

B2422.01

B2552.0112.25

B2622.018.75

B4034.0119

B4054.0113.5

B4064.0118

B4094.0110

B4434.0113

B6055.0117

C234N2.019.25

C4434.0114.25

C6035.0115

C6435.0115

CB112.51

do.do.8 (2nd P.)

CBC112.58TA13.0

do.do.6DAMax

CBC1do.7DAMax

CC112.586.75

CF112.587.25

CF212.587

CK112.577.5

CL225.086

CL430.086.0

CY230.02 5.25

do.do.2 (2nd P.)5.25

D2432.5111.5

E4064.0110.5

E4094.016.5

E4244.016

E4384.01

/ Type Range
ValveFil. Selector Degree
E4424.019.5
E442S4.0111.5
E443H4.0110
E443N4.0113.5
E4444.065.5
do.do.1DAMax
E4454.019.5
E4464.065.5
E4474.065.5
E452T4.014.75
E4544.08TA8.25
do.4.01DAMax
do.do.6DAMax
E4554.015
E4634.067.25
EBC16.38TA8.5
do.do.7DAMax
do.do.6DAMax
EBF16.38TA18.0
do.do.1DAMax
do.do.6DAMax
EB46.31DA8.5
do.do.6DA8.5
E460N4.0713.0
EF66.387.25
EF56.387.25
EK26.379.0
EL56.375.5
EL26.386.75
EL36.375.25
EZ26.328.25
do.do.68.25
EZ36.326.0
do.do.66.0
EZ46.325.0
do.do.65.0
F4434.04.0112.5
F443N4.0111.5
KBC12.08TA12.5
do.do.1DAMax
do.do.6DAMax
KC32.076.75
KDD12.0610
do.do.1 (2nd P.)10
KF12.066.75
KF22.067.25
KF32.0814.0
KF42.0812.5
KK22.0715.0
KL42.0710.0
5064.0111
do.do.2 (2nd P.)11
15614.018
do.do.2 (2nd P.)8
18674.019
do.do.2 (2nd P.)9
TA -- Triode Anode
DA – Diode Anode

D.C. MODEL

FOR TESTING BATTERY TYPE VALVES

INSTRUCTIONS FOR OPERATION

No. 1-Adjust filament voltage switch to correct voltage stud, (See chart)

No. 2-Plug in valve and test for shorts by throwing bottom right-hand switch to. the “Shorts and Ohms” position. Rotate selector switch, watching the meter needle for any deflection. If a leakage is shown the degree of same can be read on Ohmmeter Scale. The needle going over the full scale indicates a direct short circuit between two or more elements. (See Par., To identify the shorting of leakage of elements)

No. 3-Adjust “B.” battery voltage by throwing bottom right-hand switch to “B. bat. check position. Adjust to full scale by means of bottom left knob marked “B. bat. adj.”

No. 4-Turn selector and range switches to positions as shown on chart.

No. 5-Press button marked “Merit test” and read the condition of the valve directly on the good-bad ,scale.

EXTERNAL VOLTAGE READJNG.

The D.C. Model incorporates three ranges of external volts for checking all types of batteries. Throw bottom right-hand switch to “External Volts” and plug test leads into Wands Sockets at top of panel, selecting the required range.

EXTERNAL OHMS.

A means of checking resistors or condensers for leakage is available by turning bottom right-hand switch to “Short and Ohms” position. into sockets marked Ext. Ohms. Read resistance value on ohm meter scale.

AMERICAN VALVES

Type Range
ValveFil. Selector Degree
01A 5.0 1 18
1A4 2.0 8 21.0
1A62.0622
1B4 2.0 8 21.0
1B5 2.05 17.3
1C4 2.0 8 11.5
1C6 2.0 6 18
1D4 2.0 1 9.5
1F4 2.0 1 12.5
1F6 2.08TA21.0
1F6 2.0 6DAMax
1F6 2.0 5DA Max
1V 6.3 2 6
2A3 2.5 1 9
2A5 2.5 6 11
2A6 2.5 8TA9
2A6 2.5 1DAMax
2A6 2.5 6DAMax
2A7 2.5 6 8.75
2B7 2.5 8TA 17
2B7 2.5 7DAMax
2B7 2.5 6DAMax
5W4 5.0 53.5
5Z3 5.0 27
do.do1 (2nd P.)
5Z4 5.0 26.0
5Z4 5.0 1 (2nd P.) 6.0
6A4 6.3 1 9.75
6A66.3 1
do. do 6 (2nd P.)
6A7 6.3 6 8.75
6A8 6.3 1 9.5
6B76.38TA16
do.do.7DAMax
do.do.6DAMax
6C56.31 9.75
6C66.389
6D56.31
6D66.3810
6F56.387.0
6F66.3112.5
6F76.3817.5
do.do8 (2nd p.)
6H66.316.5
do.do.2 (2nd P.)6.5
6J76.3810.5
6K76.3811.5
6L66.317.25
6L76.387.5
6N76.3110.0
6N76.36 (2nd P.)10.0
6Q76.38TA10.0
6Q76.31DAMax
6Q76.36DAMax
6R76.38TA11.0
6R76.31DAMax
6R76.36DAMax

6X56.317.25

/ Type Range
ValveFil. Selector Degree
107.5118
12A5.0111.5
12Z312.525
152.585
192.0114.75
do.do.6 (2nd P.)14.75
203.31
24A2.5810
25A625.019.5
25S2.0517.25
25Z525.025
do.do.5 (2nd P.)5
25Z625.016.0
261.5116
272.5112.5
302.0116.5
312.0123
322.0819
332.0113
342.0817
352.5810
366.3810
376.3110
386.3811
396.388
40
416.3610
426.3610
4325.067.75
446.388
452.5115
462.5113
472.5111
4830.06
492.0117.5
507.5121
532.519.5
do.do.6 (2nd P.)9.5
552.48TA17
do.do.1DAMax
do.do.6DAMax
562.5111.5
572.589
582.589
592.5711.5
71A5.0116.5
756.38TA8.5
do.do.1DAMax
do.do.6DAMax
766.3111
776.319.5
786.3810.5
796.318.75
do.do.8 (2nd P.)8.75
805.0211
do.do.1 (2nd P.)11
TA – Triode Anode
DA – Diode Anode

AMERICAN VALVES

Type Range
ValveFil. Selector Degree
817.5211.5
822.5214.5
do.do.1 (2nd P.)14.5
835.0212.0
do.do.1 (2nd P.)12.0
846.326
do.do.1 (2nd P.)6
856.38TA18
do.do.1DAMax
do.do.6DAMax
896.3812 / Type Range
ValveFil. Selector Degree
TA – Triode Anode

DA – Diode Anode