Need repair for Mark V Circuit Board

Discussion in 'Scientology Technology' started by Tom of Helatrobus, Dec 9, 2008.

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  1. Tom of Helatrobus

    Tom of Helatrobus Patron Meritorious

    I just got a Mark V a few days ago and noticed the battery needed to be replaced. In a stroke of brilliance I decided I would use Nickel Metal Hydride Cell instead of Nickel Cadmium Cells. To make a long story short, I disintegrated a resistor on the circuit board while the battery was recharging. I smelled it burn up when I was flipping some of the switches while the meter was plugged into a 120V outlet. I didn't know what it was at first. But once the batteries were charged and needle was unresponsive to any switch save "test" and "sensitivity," then I knew I had a problem.

    I posted two photos of the circuit board. In the circled area are two points where the resistor once was. The close up shows two arrows pointing to two holes that should be bridged by a resistor.

    If anyone knows what resistor I need to solder back in there, it would be most helpful.


  2. Thrak

    Thrak Gold Meritorious Patron

    You should probably keep looking. There never was anything installed there. There would be solder and the resistor would still be there. Just black.
  3. Tom of Helatrobus

    Tom of Helatrobus Patron Meritorious

    Thanks for the reply Thrak,

    I was looking at this video on youtube - e-meter autopsy

    and after looking at it in high quality, came to the same conclusion that you did - there was no resistor there to begin with. So I took the circuit board away from the meter and started checking the resistors one by one with an ohm meter. I found three that were completely non responsive. I guess that must be my problem.

    Maybe I should replace all the resistors while I'm at it. There are only 17 on the board. I just want to be sure to get the right sized resistors. I'm learning a lot about electronics with this little project. My understanding is that that resistors are color coded.

    Anyhow, I'll keep at it. I should have the best damn Mark V on the planet by the time I get done.
  4. Thrak

    Thrak Gold Meritorious Patron

    Yes the color represent ohms resistance and tolerance. Radio shack should have them and you probably already know you can find resistor guides that explain the colors and what numbers they represent. Also radio shack has some good little electronics books too.
  5. ULRC/S

    ULRC/S Patron with Honors

    There never was anything between those two points you have marked in the photos. As a electronis tech of (now 45 years) I can tell you that nothing was ever soldered into those two ultra clean holes.

    My question relates to the new battery. No problem in using a Nickel Hydrid, I do that, but where/how did you get one with the required tap after one cell?

    If you have just fitted a standard 9 volt "block" cell without a tap, the meter will simply not work. There should have been three wires to the old cell, one to each end and one to the "tap".

    Regards, Allen
  6. Panda Termint

    Panda Termint Cabal Of One

    Allen's your man, Tom. He knows this stuff very well.
    I'm guessing that Cyril Holman (the former Mark V whizz-kid) is long gone?
    I still have 3 working Mark Vs (at least, they were fine last time I charged them) including my original SH Meter.
  7. ULRC/S

    ULRC/S Patron with Honors

    I was trained in e-meter repair by Cyril Holman. After I was busted off the Super post for (twice!) sending a student home early - who the Execs wanted to work all through the night for a Thurday 2PM completion , I ended up my contract days in the e-meter repair room and learnt all the tricks.

    Which was handy, becuase after I left the CoS, I designed and build a modern e-meter, and must have made and sold nearly 100 of them in Oz and the USA.

    Regards, Allen
  8. Dulloldfart

    Dulloldfart Squirrel Extraordinaire

    I think you could get away with posting a link here, or at least giving a name or something so it could be Googled. Was that the GSR meter, or something else?

  9. Terril park

    Terril park Sponsor

    Below the most comprehensive site on meters. If you look at the C-Meter site
    you will find that Ralph Hilton has instructions to build your own meter. He
    could give you technical advice also.
  10. ULRC/S

    ULRC/S Patron with Honors

    I stopped building meters about 15 years ago when I moved to Europe. I therefor doubt if my meter has ever appeared on the web, although I gave the design to the Russian Ron's Org network and al least one team is building them, or at least something similar.

    We called it a clearing biofeedback meter. No clock, no TA counter, but very clear reads at all TA positions.

    Regards, Allen
  11. Dulloldfart

    Dulloldfart Squirrel Extraordinaire

    Thanks very much Allen.

  12. Panda Termint

    Panda Termint Cabal Of One

    Yes, Allen, I remember it well. :coolwink:
  13. Tom of Helatrobus

    Tom of Helatrobus Patron Meritorious

    And since I couldn't find ANY image of a mark v circuit board on the web... here's one now.


    The switch on the left is the sensitivity booster and the switch on the right is the test-set-transit knob. There is a resistor and a capacitor(? - I'm not sure what a capacitor is, but this thing only allows current to flow one way) out of view, hiding under the switch on the right side.

    I didn't see any visible damage, but my ohm meter shows three of the resistors are not conducting any current.

    Please Mr. ULRC/S, on inspection of many of the resistors, I found that the current that went through differed when I switched the positive and negative sensors of the ohm meter on either side of the resistor. Is this a natural property of resistors, or does this mean the resistor needs to be replaced?

    For example: on the resistor fourth from the left on the bottom. When the ohm meter probe was on the top of the resistor the reading was 2500 ohms and then the negative probe was on the top of the same resistor, the reading was 1800 ohms. Does this resistor need to be replaced?

    Actually, if there was any way you could just give me a list of the capacitors I need, then I would be like "WOW - you are totally cool!"


    Tom (of Denver really)
  14. Royal Prince Xenu

    Royal Prince Xenu Trust the Psi Corps.

    As my meter hasn't sustained any internal damage, I'm unlikely to take it apart far enough to reveal the information that you're seeking.That huge yellow cylinder to the right of the photo is a capacitor. A one-way electron flow device is a diode, usually black with a silver stripe around one end (sometimes glass with a red stripe). Yes, capacitors may require replacement due to aging, but if you smelled something burning very quickly, I would suspect one of the transistors (those things wearing metal baseball hats). The numbers printed on the top should enable a tech to identify modern day equivalents fairly easily

    As it really is such a simple circuit, go out and practice removing and replacing components from an old tape deck or something, and once proficient, you should be able to do a 100% change of all components on the board fairly quickly and cheaply. The critical data needed is the test points for adjusting the trimpots--they're the adjustable blue things at the top of the photo. DON'T make any adjustment to them without that data. Because 99% of electronics are manufactured highly inaccurately (that's what tolerance means, how inaccurate), trimpots and trimcaps are used to compensate for variations in the circuit (that is what silver-certing would mostly be doing, is re-adjusting for the age of the components in the unit). If you replace a diode, the stripe must be placed at the same end! If you replace any or all of the Transistors, each of their three leads must be placed in the correct whole or the magic smoke will escape very quickly. That may mean that the modern replacement has to do some serious contortionism with its leads to comply with the origiinal layout.

    Also be warned that NiMH does not retain a charge for long periods like NiCds so you will be recharging your meter far more often. They hold a bigger immediate charge, but shelf life can be lousy. I'm fitting a standard 6 * AA carrier to the back of my Mark V, soldering the tap wire to the appropriate contact, and then I can switch batteries into a normal charger. Also, if you have cocked up the tap connection, it is one cell back from the positive end. When I've done my battery conversion, I'll post some photos to help others.

    Reminder: NiCds are TOXIC waste and should not be sent to land fill.

    If you have a Radio Shack catalog, reading resistor codes etc. should be included in the data pages at the back.

    I don't know about u.s. standards, but safety says that you should not use the meter while it is plugged in to the mains (even through a plug pack).

    I hope this is educational rather than something that scares you off your project. Just make sure all your mistakes are on a practice board, learning to get the solder out of the hole without lifting the copper tracks, and how to handle it when the solder runs and bridges two tracks etc..
    Last edited: Dec 11, 2008
  15. ULRC/S

    ULRC/S Patron with Honors

    You seem to be ignoring my point about the battery needing a 3 wire connection.

    Unless that is done, correctly, the meter flat out will not work.

    I have never had a resistor that needed changing in a Mk5 or 6, nor a capacitor, at least not that then made it work. Your measurements tell me nothing, as one cannot accurately measure resistors or capacitors in circuit. They have to be removed and tested on their own to do that.

    Answer the question about the battery connection, best show it in a photo, then we can proceed. I just doubt that you have it as it should be.

    Regards, Allen
  16. Tom of Helatrobus

    Tom of Helatrobus Patron Meritorious

    The resistor which was hiden from view in the earlier image


    The new battery pack I put together. Six AA cells in a series. Positive goes to positive and negative goes to negative and there is a white ground wire that runs from the negative side of the first battery in the series to the sensitivity switch.

    I got the eight cell holder because radio shack was out of the six cell holders, but I by passed the two cells with wire so the series can be complete. I should probably cover that with tape.


    When I put together the Nickel Metal Hydride Battery that I discussed earlier, I created it by soldering connections directly to the cells. (I have since disassembled it) The meter clearly did not like it and made a disturbing buzz while charging the battery. I think that's what fried the resistors or something relating to that.
  17. Royal Prince Xenu

    Royal Prince Xenu Trust the Psi Corps.

    At a glance, it looks like you mostly got the battery bit right, just make sure that the TAP wire is a TAP wire, not a ground wire, or you are shorting out your battery cells.
  18. Royal Prince Xenu

    Royal Prince Xenu Trust the Psi Corps.

    Emma Chissett for a set of plans, and where do you source analog meter movements of sufficient size?
  19. Dulloldfart

    Dulloldfart Squirrel Extraordinaire

  20. Tom of Helatrobus

    Tom of Helatrobus Patron Meritorious


    The battery does work and and the meter does have power. My ohm meter shows over 7 volts. When I switch the neter on "test" the needle hits against the right side. It is just that the meter will not behave as it should. When I unplug the cord that goes to the cans and set the TA at 2, sensativity to 1 and turn the "test-set-transit knob" to "set" the needle does not move it just sits on the left side and no amount of calibration or trim will move it.

    Royal Prince Xenu,

    Thanks for the information on electronics - I really need it! I did smell something burning before everything went haywire and I didn't really consider it could be on of the transistors (a transistor you say?). Is there a way I could check for that on with a multi meter? On the e-meter autopsy video, the speaker says that those transistor things are not in use any more and made with germanium. I guess I should look it up. I might as well replace those as well. If I go down the route of replacing things.


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