MARK V E-METER
Battery Change and Calibration
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Courtesy of
Tommy Thomson
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CONTENTS
Layout
Printed Circuit Board (PCB) Tips
Tinning the battery connecting points
TESTING THE BATTERY
Using the E-Meter to test the new battery
CALIBRATION
Identifying the trimmer resistors
Adjustments: (internal settings)
Final testing and reassembling the meter
External event checks and adjustments
Preparing the meter for transit or storage
INTRODUCTION
The batteries of all E-Meters fail after extended use. Replacement thereof usually means that the meter must subsequently be recalibrated.
It may also be found that a meter requires recalibration although its battery is still functioning satisfactorily.
This not intended to comprehensively address these subjects or for that matter repairing the meter but merely to guide one in performing a battery change and calibration.
Scientologists on the Church of Scientology lines are recommended to have their meters silver certificated along the usual lines.
An E-Meter is a measuring device having internal circuitry intended to reflect input from an external source in such a manner that the meter will indicate any change coming from the external source in a standard manner.
As with all electronic measuring devices their internal circuitry require periodic calibration to ensure that they function correctly.
Recalibration becomes necessary due to usage (wear) or component deteriorization, the latter is usually ascribed to oxidization (corrosion). Another opportunity to recalibrate occurs when the battery fails and must be replaced.
Component function and frailties
Variable resistors
Variable resistors, also called potentiometers (pots for short), as well as trimmer resistors, function on the bases that their resistance can be adjusted within given limits. For example: A variable resistor may be so designed as to be able to be adjusted from say 10 ohms to 50 ohms. Their design parameters may vary considerably depending on the function they have to serve.
Figure 1a
Figure
1a depicts two types of variable resistors. One has the resistance material laid
out as a straight strip and the other in a circular configuration. Both have a
fixed contact point and a movable contact point.
The resistance will increase as the movable contact point is moved closer to the fixed contact point. This is because less semi-conductive material is made available, hence less free electrons are made available resulting in a decrease of flow of electricity, that is, more resistance is introduced into the circuit.
If a variable resistor has not been moved for some time the surface where it is not making contact tends to deteriorate. This means that when the variable resistor needs to be readjusted from its current point of contact, it may be found that it had become unstable due to disuse. Oxidization (corrosion) or dirt has contaminated the resistor’s contact surface. In many instances the contact surface can be cleaned by merely moving the movable contact point from its lower to upper limit a couple of times.
Its surface may also become worn from use and will therefore not stabilize with cleaning .If this is the case the variable resistor must be replaced.
The Tone Arm, Sensitivity knob, Trim knob and internal trimmer resistors are all variable resistors.
Tone Arm
Figure 1b
As
the movable contact point in figure 1b is moved from 0.5 to 6.5 in a clockwise
direction, more and more resistance is introduced into the circuit.
A theoretical infinite quantity of resistance will be introduced at the point marked infinity (beyond 6.5).
Viewed from the infinity mark towards 0.5 a theoretical infinite conductivity, zero resistance, increasing to a measurable resistance at 0.5 is introduced into the circuit.
As infinities, plus or minus, cannot be achieved in practice the meter must be so designed as to reflect an infinity of resistance upon an open circuit, that is when there is nothing but air across the contact points.
This means that the tone arm must be calibrated to correctly reflect “infinity” in the area between 6.5 and 0.5.
Because most auditing is done in the area 2.0 to 3.0 these points on the tone arm scale must be calibrated to represent the most standard reflection of external events when the tone arm is positioned in this area.
It is furthermore imperative to realize that any trimmer resistor that is used to confirm a setting of another variable resistor must be accurate before commencing tests aimed at confirming the accuracy of the variable resistor in question. For example: If a position on the Tone Arm is to be checked and the accurate placing of the Tone Arm on this position, say tone arm position 2, is dependant upon the adjustment of another variable resistor, say the Trim knob and the accuracy of the trim knob is can be calibrated. Then calibrating the Trim knob must be done before attempting to place the Tone Arm on its position 2. In similar fashion the tone arm may require calibration before using its setting to perform the calibration of a function dependant upon the accurate placement of the tone arm.
The needle balance
Figure 1c
As
with all electro mechanical devices the needle must be calibrated to deflect
from a standard point. This point is the set line shown in figure 1c.
If, upon testing the “balance” of the needle, it is found to stray beyond the limits of the set area, recalibration is indicated.
Summary
We therefore have three critical internal calibration settings to perform. These are:
Note that when the needle balance is calibrated it is done with the tone arm set to 2 (the female position).
In order to check whether the meter reflects external inputs correctly it is checked with external fixed resistors: 5000 ohms for a female clear and 12500 ohms for a male clear.
LAYOUT
Slide 1
Screwdrivers: to remove fixing screws and a small screwdriver with which to adjust the trimmers
Light soldering iron and solder wire, preferably of the resin core kind that does not contain an acid
based cleansing agent.
Wire Cutter.
Insulation tape.
Suitable adhesive (double sided tape or contact adhesive) to secure the new battery into position.
Short length of single core 0,4mm or 0,5mm tinned wire.
6 x AA rechargeable batteries. (1.5V each).
Volt meter (optional)
Sharp knife
Clean and “tin*” all points and wires to be soldered.
*Tinning is the process of pre-soldering a contact point or wire to allow a) an improved contact of the soldered connection and b) to minimize the time needed for the solder to flow and adhere when soldering the leads into position.
Use an appropriate soldering iron. Too light a soldering iron may need to be held on the solder point for a longer time to allow the surface to heat up to the required temperature for the solder to adhere, thereby overheating and possibly damaging the component or wire insulating material.
Use resin core solder wire instead of acid based cleaning solvents during soldering because acid based solvents cause a minute “battery” to develop due to chemical reactions with the metal surfaces. Acid contribute to corrosion.
PRINTED CIRCUIT BOARD (PCB) TIPS
A PCB has components mounted on one side and is soldered on the other side.
The sides are referred to as the front (or component) side and the back or (solder) side.
Component identification markings may be paint printed on either the components themselves, the front or back of the PCB or both sides. Some component markings consist of engraved copper plating (same material as the tracks on the back side of the PCB).
On some old PCB’s no markings were put on either the PCB or the trimmer resistors.
The American Mark V can be distinguished from the British Mark V E-Meter by its blue colored face plate. The British Mark V has a white face plate.
For the slides included in this document an American Mark V was used.
Note that although these meters, as well as different models that were released over the years, all operate on the same basic principles. This document can therefore be used as a general guide line for all Mark Vs.
The American Mark V has a side panel that must be removed to access the circuitry.
(The British Mark V can be opened by removing the screws fixing the face plate to the meter box.)
Remove the side panel fixing screws as shown in slides 2 and 3. The screws may be covered with wood-putty which must be removed before access can be gained to the screws. The fixing screws are located on the sides and back panel.
Slide 2 Slide 3
Loosen the side panel and slide the PCB out as shown in slides 4 and 5 so that you have the circuitry available as shown in slide 6.
Slide 4 Slide 5
Slide 6
This particular meter has previously had a battery change as can be seen in slide 7 (original clip for the round battery) and slide 9 (previously changed battery). Slide 8 shows an original round battery.
Slide 7
The battery leads would run from this
mounting position to the PCB.
Note that the color of the battery leads
may differ from those depicted.
Slide 8
Slide 9 shows a battery built up from 6 standard, rechargeable AA batteries. It is equipped with battery holders, the black plastic holders at both ends of the battery. It is not recommended to use battery holders because the interconnection points of the cells maintain contact under pressure from the springs of the battery holders and may cause the cell to over heat if the springs lose tension resulting in poor contact. The batteries (cells) can be interconnected as described under New battery layout.
Slide 9
Cut the battery leads on the battery’s side taking note which wire goes where and the color of the wire.
The color coding of the battery leads are usually red, for the positive terminal, and black for the negative terminal of the assembly. On a single cell the positive terminal is marked with a + sign. The body of the cell (bottom end) is the negative terminal, as shown in figure 4. In this document a single AA battery will forthwith be referred to as a cell of the battery assembly.
Figure 2a
Figure 3 shows the circuit layout of the battery assembly. The cells are connected in series; that is the positive terminal of each cell is wired to the negative terminal of the next cell so as to add the voltage of each cell to that of the next resulting in an assembled battery capable of delivering 9 volts. (6 x 1.5V = 9V). As can be seen from fig. 3, a third lead is wired to the negative terminal of the sixth cell for internal comparative purposes. The coloring of the leads are not important provided that the leads are wired to the correct points on the battery as well as the PCB.
Figure 2b Figure 2c
Lay the cells on insulation tape, to hold them together, and arrange them in such a manner that their positive and negative terminals alternate as shown in slide 10 and detailed in figure 2b. Figures. 2b and 2c also shows an electrical diagram (bottom of View A), the proposed cell interconnecting straps (the dark lines interconnecting the cells in View A and where the assembled battery connecting leads are connected Figure 2c (View B).
Slide 10
View A and view B below depend on which side is considered to form a view from the top of the assembly. The cells must be arranged as sown in Figures 2a and 2b.
Although it does not matter how we number the cells it would be wise to use a standardized numbering system by assuming that view A represents Fig 2c (View A) and when the assembly is turned upside down view B represents Fig 2c (View B).
Figure 2d
When
holding the assembled cells as shown in Fig 2d (View A), and counting from the
top down cells 1 to 3 will be on the left and cells 4 to 6 on the right hand
side, counting from the bottom. The cells must be interconnected as shown with the dark lines. Thus
the negative terminal of cell 1 must be connected to the positive terminal of
cell 2; the pos of cell 6 to the neg. of cell 5 and the neg. of cell 3 to the
pos. of cell 4. When turning the assembly over (View B) the interconnections will be
between the pos of cell 5 and the neg. of cell 4; and the neg. of cell 2 and the
pos of cell 3. This will ensure that all of the cells are connected in series
thereby resulting in a final voltage of about +9V depending on the type of cells
being used. AA marked cells are usually rated at 1.5V per cell and some AAA
rated cells are rated at 1.2V per cell.
Tinning the battery interconnecting points
Before making the soldered connections it is wise to prepare the points where we want to connect the wire jumpers. This can be done by adding a drop of solder to each point where we will be soldering a jumper or finally the battery leads.
Slide 11
After the six connecting points are tinned on one side of the assembly, it is turned over and the remaining six points tinned.
Slide 12
Cut a length of about 10 cm of 0.4mm or 0.5m, solid core, tinned bare wire. Un-tinned wire or badly corroded wire must first be tinned. Stranded wire is not recommended unless the strands are properly soldered together to form a single strand. Add the cell interconnections laying the bare wire across the points to be connected and soldering them into position. Trim any excess wire with a wire cutter. Use the layout shown in Fig. 2d. above.
Cleaning the leads
Slide 13
If the copper of the battery leads (the black, red and white wires) are corroded it is wise to clean them by scraping the corrosion off with a sharp knife taking care not to break or cut the copper strands. In some cases it may be necessary and advisable to replace excessively corroded leads by unsoldering them from their connecting points on the PCB and replacing them. Allow sufficient length of the battery leads for them to reach from the battery to the PCB with the battery mounted in an out of the way of the meter components. If the color of corroded leads is not a bright shiny copper and is dark and discolored the leads will not tin properly and cause poor electrical contact. This is most noticeable with the negative leads. After cleaning the leads they must be tinned before being soldered onto the cells.
Tinning the leads
Slide 14
Soldering the battery leads
The red, white and black battery leads are soldered into position as shown in slide 15 and in accordance with Fig. 2c and 2d. The black lead goes to the negative of cell 6. The red lead goes to the positive terminal of cell 1 and the white lead to the negative terminal of cell 1 (Fig. 2c).
Slide 15
TESTING THE BATTERY
Testing with volt meter (optional if a volt meter is available)
The polarities of the battery can be tested with a volt meter to ensure that they are correct and also that all of the connections are properly soldered. Check to see that the voltage between the negative (white) and the red lead reads 1.5V and the voltage between the negative (black lead) and the red lead reads 9V. (See slide 16).
Reassemble the meter and check that everything can be accommodated in the meter box. Do not insert the fixing screws at this time.
After inserting and connecting the battery it can also be tested by switching the Test-Set-Transit knob to Test and switching the meter on by turning the Sensitivity knob On-Off switch to On, on the E-Meter. The needle should swing hard over to the right. (See slide 17).
Test with a volt meter Test using the E-Meter
Slide 16 Slide 17
CALIBRATION
Identifying the trimmer resistors
Slide 18 shows the trimmer resistors. Note that they are mounted onto the front side of the PCB. Their markings are brought onto the back side of the PCB as can be seen in slide 19. Therefore the left-hand trimmer resistor is M, the middle one B and the right-hand one I. B = Balance, M = Male and I = Infinity.
Slide 18
Note that for your meter the positioning and markings may be different. If there are markings they will appear apposite the trimmer resistor in question. If there are no markings, set the meter up for the appropriate adjustment and turn each trimmer resistor until the one is found for the adjustment being performed taking note of its position on the PCB. Identify and mark the trimmer resistors M, B, and I for current and future use .
Slide 19
To adjust the trimmer resistor, insert a screwdriver (preferably non-metallic) into the slot in the center of the resistor and turn it to the left or to the right.
Controls
The infinity setting is done with the tone arm set at its maximum 6.5+.
With the leads plug plugged in but not connected to any external resistors, check that the infinity setting is correct by setting the tone arm to 6.5 (the maximum that it will travel in a clock-wise direction) and observing that the needle is on the set line (See fig. 1).
If not, use the infinity (I) trimmer resistor to bring the needle onto the set line.
Controls
Use the Trim knob to bring the needle to the set line (see fig.1, under LAYOUT above) and slide 20.
Slide 20
Checking the needle balance
Turn the sensitivity knob from 32 to 1 and back. The needle must not appreciably move from the set line and certainly not beyond the set area. If it does, adjust trimmer resistor B to limit the deviation.
Periodically test the adjustment results by removing the screwdriver from the trimmer resistor (especially if it’s a metal screwdriver) and turning the sensitivity knob from 32 to 1 to 32.
If the needle response remain erratic see Component function and frailties above.
Once the needle does not move from the set line upon testing, the needle balance is properly calibrated.
Controls
The male (12500 ohms) calibration resistor for this meter is mounted at the bottom of the inside of the meter box lid and the female calibration resistor (5000 ohms) at the top. (See slide 21).
Slide 21
Connect the alligator clips to the male calibration resistor and plug the leads plug in. In slide 22 the alligator clips are shown in the top left hand corner and the leads plug in the right hand bottom corner.
Slide 22
If the needle is not on the set line, use the male trimmer resistor to bring it onto the set line.
Once this is done the male setting has been calibrated.
After completing the male calibration, unplug the leads plug, set the tone arm to 2 (being careful to put it exactly where you had it when calibrating the needle balance) and confirm that the needle still is on the set line.
If the needle balance has drifted slightly when repositioning the tone arm from 3 to 2, it could be contributed to not having the tone arm exactly on the same position as when the needle balance was initially set.
[The Mark Super VII and Quantum E-Meters are equipped with a digital tone arm display that allows setting the tone arm to within 100ths of a TA division, thus allowing the setting of the tone arm to exactly 2.00 or 3.00 for calibration purposes].
Final testing and reassembling the meter
Before reassembling the meter recheck the infinity setting, needle balance and male setting to ensure that none of these had drifted while calibrating any of the other settings.
If all is within limits reassemble the meter making sure that none of the parts are placed under stress. If necessary the new battery may be secured into position with contact adhesive or double sided tape to prevent it from being knocked about during transit of the meter.
Standard meter setup (external event checking)
1. Take the lid off the E-Meter.
2. Put the lid onto the far edge of the E-Meter and secure into position with catches.
3. Turn the Sensitivity Booster to 32.
4. Turn the Sensitivity knob to 32.
5. Take the following steps to check the meter for charge:
a. Turn the Tone Arm all the way counterclockwise.
b. While watching the needle, turn the Set-Transit-Test knob to Test. (If the needle bounced smartly off the right-hand pin and then rested against it, carry on with the next step. If not, charge the meter per the owner's manual and then repeat step 5.)
6. Turn the Set-Transit-Test knob to Set.
7. Turn the Tone Arm to 2.0.
8. Adjust the Trim knob until the needle is at the Set line on the needle dial.
9. Take the following steps to check the condition of the leads:
a. Inspect the leads at each end for any obvious signs of damage.
b. String the electrode leads between the E-Meter and the lid, from the left of the meter to the right, and plug the jack plug in completely.
(For left-handed meters: String the electrode lead between the E-Meter and the lid, from the right of the meter to the left, and plug in the jack plug completely.)
c. Firmly attach the alligator clips to the 5,000-ohm resistor.
d. Wiggle the leads near the clips and then near the jack while observing the needle. (The needle should not move. If the needle moves, replace the leads and repeat step 9.)
e. Unclip the 5,000-ohm resistor.
10. Clip the leads onto the electrodes.
11. Place the electrodes, not touching each other, in a position on the table for the preclear to pick up.
12. Check for correct functioning of the Tone Arm counter by moving the Tone Arm downward and observing the counter.
13. Set the Tone Arm counter at 0.
14. Set up a shield to obscure the meter Tone Arm and worksheets from the preclear's view.
[Ref. EM-4: The Book of E-Meter Drills 1997 Edition].
Preparing the meter for transit or storage
1. Turn the Tone Arm fully anti-clockwise.
2. Turn the Sensitivity knob On-Off switch fully anti-clockwise to switch the meter off.
3. Switch the Test-Set-Transit knob to Transit.
END
