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cap tester repair

Discussion in 'Troubleshooting and Repair' started by pete g, Jan 8, 2019.

  1. pete g

    pete g

    79
    2
    Sep 14, 2010
    it measures 1.8meg
     
  2. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,174
    2,690
    Jan 21, 2010
    Hmmmm... That's not wildly high, but it may be worth replacing. I doubt that it is causing the current problem, so it's not something I'd do right now (unless you have a replacement 1.5M resistor on hand).

    Try the tests that Edd is suggesting. I'll take a deeper look at the schematic. There may be other components that could cause this bias problem.
     
  3. pete g

    pete g

    79
    2
    Sep 14, 2010
    HI EDD, I just realized what the diagram is. will be using it. thanxs.
     
  4. pete g

    pete g

    79
    2
    Sep 14, 2010
     
  5. 73's de Edd

    73's de Edd

    2,644
    1,074
    Aug 21, 2015
    MINOR SCHEMATIC LABELLING ERRATA . . .

    WHERE ?
    On the large UNITIZED schematics, right center half, on the BRIDGE-DISCHARGE-LEAKAGE SWITCH and its section A on the left.

    WHAT ?
    The RED inset info of the switches closures in LEAKAGE mode is erroneously showing a #3 to # 5 contact connectivity closure, while one sees that it is actually #4 to # 5.

    WHY ?
    You tell me . . . . . . senility onset ?


    Dear Abby:
    My mommy is mean and very short-tempered. I think she is going through her mental
    pause.
     
  6. pete g

    pete g

    79
    2
    Sep 14, 2010
    yes, I see it. love your jokes.
     
  7. pete g

    pete g

    79
    2
    Sep 14, 2010
    checking out wiring, per your diagram. making good progress.
     
    (*steve*) likes this.
  8. pete g

    pete g

    79
    2
    Sep 14, 2010
    slight diversion. an iguana has taken up residence in my garage. trying to figure a way to get rid of him. I dont't think I want to touch him. ugh! anyway, hve checked wiring as per edd's excellent diagram. no errors found. one quesrion. with the type switch in mini and the volt sw ser at 25v b-d-l in leakage, if I read between pin 8 6bn8 and pin 7 of type sw should I read the 1.5m (r6)?
     
  9. pete g

    pete g

    79
    2
    Sep 14, 2010
    edd, have checked r8 meas 245k. c4 and c11 checked both for leakage at 100v and value, o.k. r12 checked good, also.
     
  10. 73's de Edd

    73's de Edd

    2,644
    1,074
    Aug 21, 2015
    Sir Pete g . . . . . ..

    if I read between pin 8 6bn8 and pin 7 of type sw should I read the 1.5m (r6)?


    The voltage designating aspect of the eye tube is related to the left half of the schematic and the PURPLE mark up portions, with one variance, in the respect of there also being a complete loop around with one of the PURPLE arrow path over to the right side.

    There is the series arranged voltage divider trio of the R6 on top which goes down and ties into R35 and then R34 goes on down and grounds.
    The resistance reading across R6 can vary in accordance as to how TYPE SWITCH section A is set.

    If it is in PAPER MICA TEST the switch should not be closing any connections related to those three resistors.

    If you then switch to MIN'LYTIC, look and see if your top lead of R6 (same as #8 of the 6BN8 ) is then going into the PURPLE arrow loop going to the right, then going extreme right and down and into and out of the terminals #6 to #10 of the B-D-L switch.
    Then it continues to the left until it goes up and ties into #9 of the TYPE SWITCH Section A which connects to #7 and passes over and right up the PURPLE arrow path to effectively short out R6. ( Confirm this)

    If you switch to ELECTROLYTIC expect the 47K resistor being shunted across R6. (Confirm this)

    So you would want to test R6's resistance value by being in the PAPER MICA position and you could further double check by switching the B-D-L switch to BRIDGE or DISCHARGE position to switch open that otherwise closed PURPLE loop around.
    Or, an utter finality would be floating the top or bottom lead of R5 out of circuit for measuring.

    If doing that R6 resistance reading myself . . . to preclude any potential soldering heat shifting of R6's value into a change, I would lift / clip / unsolder either joining " PURPLE " wire, on either of the sides that feeds into R6.
    That keeps excess soldering heat far- far away from R6.

    73's de Edd . . . . .
    . . . . . . . . . . . .


    Text message found, left on mobile phone . . .
    370HSSV 0773H
    ? ? ? ? ? ? ? ? ? ?

    (HEY . . . .you're looking at it upside down, dummy !)

     
    Last edited: Jan 16, 2019
  11. pete g

    pete g

    79
    2
    Sep 14, 2010
    o,k, thank you, edd.
     
  12. pete g

    pete g

    79
    2
    Sep 14, 2010
    steve, I don't understand what this is? do I need to do something?
     
  13. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,174
    2,690
    Jan 21, 2010
    You replied to yourself.

    I originally suggested that you check all the wiring to ensure there wasn't a construction error, however you assured us that it was once working correctly.
     
  14. pete g

    pete g

    79
    2
    Sep 14, 2010
    well, its been awhile since I messed with this thing. to the best of my recollection it worked o.k. but, you know I started to check the line that feeds the grid of bn8, and noticed a lot of noise with some big spikes. as far as the wiring I checked , and can"t find errors. can the noise on the grid, be the problem? I do have an old sencore sc61 scope that I used to scope that line. I disconnected the lines on pin 6 & 10 on the bdl switch and the noise is still there.
     
    Last edited: Jan 16, 2019
  15. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,174
    2,690
    Jan 21, 2010
    I reviewed an article recently that spoke of the experience of those who worked for Heathkit "fixing" problems caused by people's kit construction.

    The observation was that, very frequently, problems were resolved simply by fixing poor soldering -- dry joints being a common issue.

    Another observation was that almost every kit had at least one wiring error (wrong component, something connected to the wrong point, etc).

    If you're seeing noise, I would certainly be checking for poor solder joints. This is especially true if the noise can be affected by mechanical action.
     
    Last edited: Jan 17, 2019
  16. pete g

    pete g

    79
    2
    Sep 14, 2010
    well then, i'll resolder all the joints.
     
  17. pete g

    pete g

    79
    2
    Sep 14, 2010
    I resoldered all connections. I hung a 22ufd cap on the line that feeds the bn8 grid. that got rid of the noise and also enabled me to calibrate the min lytic position. the mica,etc. position still is a problem. somrtimes it will calibrate, but then open again? that's it for now.EDD I confirmed both items you suggested. (r6 being shorted,etc.)
     
  18. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,174
    2,690
    Jan 21, 2010
    I wonder what condition the switch contacts are in after so many years?

    I don't suppose you have any contact cleaner?

    I watched a YouTube video of someone building a Heathkit project. They discovered that quite a bit of work was needed to get some of the switched working. The same issue might also apply to the trimpots.

    Does the resistance across the trimpots vary smoothly as you adjust them? Do the switches read read a very low and consistent resistance?
     
  19. pete g

    pete g

    79
    2
    Sep 14, 2010
    yes I used deoxit on the pots followed by a lubricant. I did find a wiring error going to the trimpots, which I corrected. what happens now is in the mini-lytic and mica,etc., the eye closes when I adjust those two pots when calibrating but then start fluttering open and close. what resistance should I read from pin 15 of bdl switch and pin 2 and 5 to ground of the type switch? what confuses me is that with the voltages so far off the problem should be be obvious. switch contacts good.
     
    Last edited: Jan 19, 2019
  20. pete g

    pete g

    79
    2
    Sep 14, 2010
    hi steve and edd. I just wanted to thank you for all your help. i'am going to shelve this project for now. your help was much appreciated.pg
     
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