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  • September 15, 2016 at 9:16 pm in reply to: Electro Harmonix Bad Stone repair #122046
    Jimmyz91164
    Member

    HALLELUJAH !
    Finally after looking at this broken phase shifter it LIVES AGAIN !
    My guessing game ended thankfully sooner than expected.
    After changing out the following components in order.
    F2n5088 (appeared cracked/chipped)
    CD4009AE RCA chip
    100uf cap
    10uf cap
    1 uf cap
    1n914 diode with 1n 1n4148
    Last but not least fresh out of the mail box the LM324N.
    The 470 uf cap still needs to be changed,it is on the way but it sounds great as is.
    Been many years since hearing one of these again and glad it is now inline with my system.
    The missing link to my life…haha.
    Thanks for the help and schematic.
    Very happy today,back to jammin` !

    September 15, 2016 at 5:56 pm in reply to: Electro Harmonix Bad Stone repair #122045
    Jimmyz91164
    Member

    Sorry to post all this,but again tested the battery ground and battery connection and there is no continuity.I may have made an error on that.
    However,with meter to ground connection from battery to the input jack,should I not have continuity to chassis?
    It seems that the grounds are all connected from the input/output,switch…etc.
    Not sure why the meter does not show any continuity.
    Found all but the 470uf cap replacements here and swapped what I had out and tried it again,nothing.
    Still clean sound with FS off and slightly less sound with ON position with a more bass or muffled tone.
    When I turn the Feedback knob full,I hear a slight change in tone.
    While the amp is plugged in and the battery power is removed or applied,it makes almost a brief phase shift noise.
    All I got for now.
    Going to note the pin voltages now from all IC chips.

    September 15, 2016 at 2:24 pm in reply to: Electro Harmonix Bad Stone repair #122044
    Jimmyz91164
    Member

    With the multimeter ground connected to the battery ground,I am seeing full battery voltage on every pin on one of the op amps.I get full batt voltage off the chassis too.
    There is a dead short to ground somewhere.
    Hope everything is not toasted.
    Rechecking wiring and just do not see anything mis wired.
    Going to really look this over today one trace at a time.

    September 15, 2016 at 1:45 pm in reply to: Electro Harmonix Bad Stone repair #122043
    Jimmyz91164
    Member

    Ordered 20PCS JRC4558D 4558D DIP8 OPAMP OP AMPS CHIP IC ,think you mean these?
    Also have a ST Microelectronics LM324N Quad Opamp on the way.
    Yes,I would like original,dirt and all to be honest.
    I got this thing for free and had it a long time.Now my focus is to get it up and running finally.
    So just ordered the parts just to have them here.
    Saves me weeks of waiting.
    Now,still puzzled why I get continuity between the voltage connection and chassis.
    I believe the wiring is ok after searching every photo online available.
    Let me see about the op amp voltages and will write them down.

    September 15, 2016 at 1:38 pm in reply to: Electro Harmonix Bad Stone repair #122042
    Jimmyz91164
    Member

    #3 new photo

    September 15, 2016 at 1:38 pm in reply to: Electro Harmonix Bad Stone repair #122041
    Jimmyz91164
    Member

    #2 new photo

    September 15, 2016 at 1:27 pm in reply to: Electro Harmonix Bad Stone repair #122039
    Jimmyz91164
    Member

    My photos are crappy.If you need better ,let me know,going to see if I can improve on those.
    It will not allow me to send hi res.

    September 15, 2016 at 1:17 pm in reply to: Electro Harmonix Bad Stone repair #122038
    Jimmyz91164
    Member

    [img]Here is another view.[/img]

    September 15, 2016 at 1:15 pm in reply to: Electro Harmonix Bad Stone repair #122037
    Jimmyz91164
    Member

    [img]Thought I had uploaded a photo but do not see it.
    I will take a fresh photo now and see if it will upload.
    Just removed the power wire from the adapter jack and checked continuity directly from the main connection on PCB to ground and I have continuity.
    That is not good already.[/img]

    September 15, 2016 at 12:43 pm in reply to: Electro Harmonix Bad Stone repair #122034
    Jimmyz91164
    Member

    Just put the meter on to test some voltages and found something odd.
    I clip my ground to the battery ground that is soldered to the input jack and get 9v+ off the main chassis.
    Now that is wrong !
    When I got this box,it had wires pulled off the PCB and such.I used photos online to put them back.
    Something needs to be figured out on this.

    September 15, 2016 at 12:16 pm in reply to: Electro Harmonix Bad Stone repair #122033
    Jimmyz91164
    Member

    Your right,I hate diagnosing circuits as I am not so good at that sort of thing.
    Although I do build new circuits with success you would think I would be better than I am.
    I saw the parts were inexpensive and felt why not have them around anyhow since they will eventually be impossible to find soon.
    Also had a plan to possibly build an entire new circuit from scratch,PCB and all.I may even draw up my own diagram using Eagle software and order a PCB.
    Today I will check the electrolytic`s,they are old and usually an automatic replacement.
    Testing components need to be removed from the circuit,swapping with new seems easier since they are already removed.I have no diagram for this model or parts specs.Have to go through everything by color code or markings as you know.I found one schematic that resembles this circuit and need to go through it carefully and trace everything.
    Thanks for the reply

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