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  • #38142
    Ben Ji
    Participant

    Regarding Q5 2N4125, i have tested a few from the bag i have (x10) i didn’t touch the one on the board.
    I used the FNIRSI LCR-P1 which provides:
    – DC current gain -> hfe,
    – base-emitter voltage drop -> Ube,
    – Ic/Ie, collector-emit-ter reverse cutoff current -> Ice

    Here are the values for 3 FET i took from this bag (new), i’m not sure these value matches the datasheet. What do you think? It is difficult to say because there are so many values.

    #38143
    Ben Ji
    Participant

    the speed pot affects voltage on Pin2 up or down a bit if i turn it clockwise or counterclockwise but does not oscillate ‘alone”. Pin6 voltage does not change when i turn the speed pot

    #38145
    Billy
    Moderator

    Does pin 6 voltage still oscillate regardless of the speed pot

    It should if pin 2 oscillates

    Try reflowing C8 solder joints

    I’ve got a phase 90 circuit somewhere I’ll try to find it and confirm voltages etc unfortunately I had to empty my workshop to get some work done to my house recently so hopefully I’ll find it easily enough

    #38150
    Ben Ji
    Participant
    • Pin6 clearly does not oscillate
    • I tried reflew C8 solder joints

    What do you think about the JFET values i gave ? does it look good to you?

    #38151
    Billy
    Moderator

    Those look like pnp transistors not jfets

    #38152
    Ben Ji
    Participant

    i agree.. i need to source proper ones. this pedal will not work with this PNP. thanks!

    #38153
    Billy
    Moderator

    It should work OK with any pnp transistor and your matched set of jfets if the LFO isn’t oscillating that’s your problem I’d check all components in that section

    I’ve had solder joints that looked perfect but where dry inside not often but you never know

     

    #38171
    Ben Ji
    Participant

    OK i’ll try to reflow a few of these around and let you know how it goes. thanks a lot

    #38225
    Ben Ji
    Participant

    i reflew around C8 , R22/24/25 + IC3 socket. no progress

    #38233
    Billy
    Moderator

    Check you’ve got a good connection to G2 I’d personally have wired it direct to the DC jack

    Remove IC3 from its socket and let us know the voltages on the socket

    #38239
    Ben Ji
    Participant

    <span style=”-webkit-tap-highlight-color: rgba(0, 0, 0, 0);”>g2 is very well grounded i have verified it is connected to the jack and from the jack i go to another ground.</span>

    with no IC3 we have

    L2: 2,5/2,3v
    L3: 3,7/3,8v
    L6: 2,8v
    L7: 8,9v

    all other Lugs are 0v

    #38240
    Ben Ji
    Participant

    is  this what you call oscillate ? this is Lug 6 after i replaced IC3 with a more trustworthy supplier. did not test the pedal yet but i can tell you i never had this on this Lug

Viewing 12 posts - 18 through 29 (of 29 total)
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