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Viewing 9 posts - 1 through 9 (of 9 total)
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  • September 9, 2018 at 1:50 pm in reply to: Vintage Zipper Envelope Filter #124296
    Camarada78
    Participant

    Hi. Thanks a lot for the help. I discovered the problem: either me or the other repair guy around here connected the DC PS ground cable to the “ground reference” (the “0v of the symetric supply”) making the pedal not work with the DC PS , only with battery.

    Thanks a lot for the help. Your insights were important.

    Have a good day!

    August 23, 2018 at 9:53 pm in reply to: Vintage Zipper Envelope Filter #124226
    Camarada78
    Participant

    Quick update.

    I manage to make the pedal work as intended, but it only works on 9v battery, not on DC power supply.

    I need to make it to work on DC PS.

    1. the DC is working and sending 9v to the diode (D6).
    2. I get 8.8v on the emitter and nothing after that.

    August 22, 2018 at 9:44 pm in reply to: Vintage Zipper Envelope Filter #124221
    Camarada78
    Participant

    Hello again Scruffie,

    So long no see.

    After almost two years of studying other things and abbandoning that pedal, i’m back at it again (a matter of honour).

    so, the pedal is now dead both in battery and power supply. I did not touch it since those days. Anyway.

    thanks for the help btw.

    weird things:

    1. I get 9v on 2n5088 collector, but not on the emitter. I changed the transistor, the problem remained.
    2. Therefore i get no power after the transistor. no matter what i do, i tested another two npns and the same.
    3. changed the capacitor (c15) and nothing.

    Should i bypass this transistor, remove the battery and feed the DC signal straight to the voltage divider (r29)?

    March 30, 2017 at 6:31 pm in reply to: Vintage Zipper Envelope Filter #122735
    Camarada78
    Participant

    Hello again scruffie.

    I’ve managed to make the pedal work again, but now it only works with batteries, not with the DC power supply.

    I’m trying to rebuild this pedal on Proteus using your schematic, but some points are a little confusing.

    Can’t understand the power section to proper translate it to Proteus. Where it is written AC adaptor, should i put an AC 9V power source?

    July 8, 2016 at 2:13 am in reply to: Vintage Zipper Envelope Filter #121713
    Camarada78
    Participant

    My friend. Thanks again for the help. I’m learning a lot about this pedal.

    It is still dead.

    there is no voltage after the C15 (Capacitor 0.1uF). I tested it and it is reading right, 0.107uF as it should.

    But there is no voltage after it anywhere in the circuit.

    No voltage is getting to any IC as it did before.

    It is very weird.

    July 6, 2016 at 5:45 pm in reply to: Vintage Zipper Envelope Filter #121711
    Camarada78
    Participant
    Quote:
    Have the voltages changed? On the 324 you should be seeing roughly the same voltage on pins 8 & 9 as you are on pin 10 (it’s a buffer for the reference voltage which should be half supply, pin 10 where the voltage reference enters is a little low but that could just be down to tolerances or value drift) hence why I suggested that cap and the 324 its self.

    On your voltages where you list ‘nothing’ on the ICs that’s where the bias voltage should be seen so something is causing an issue there.

    Here’s my redraw of the factory schematic for reference;
    EHXZipperSchem.gif

    Thanks for the schematics. I have the old one (hand written).

    Now the pedal is completely dead and I dont know why. After I changed the CI and 100uF cap it – as i said – remained with the same problem as before (i could hear the oscilator filter but it was not affecting the guitar sound). But now is dead. No voltage in any CI.

    I’m going to check the caps or check every resistor to see if any has broken and opened the circuit.

    July 5, 2016 at 8:47 pm in reply to: Vintage Zipper Envelope Filter #121708
    Camarada78
    Participant
    Quote:
    By the looks of it (and assuming the PCB pin outs match up to the schematic) either the 324 is dead or the 100uF cap coming off pin 8 has gone bad and become a short.

    So give the cap a test for continuity and then i’d swap out the 324 if that’s not the case. You could also check for continuity between the 324 pins and the PCB, the traces on the old EHX boards do have a habit of breaking.

    Hi, thanks for the help. Changed the 324 and the 100uF cap and the problem remained the same: intermitent sound, like if the oscilation was working, but it is not affecting the guitar sound, so i only receive the “empty” output sign of the pedal itself, without the guitar sound.

    the bypass works btw.

    June 28, 2016 at 9:22 pm in reply to: Vintage Zipper Envelope Filter #121690
    Camarada78
    Participant

    Thanks, i’ll test and give feedback. My guess would be the caps. The ICs are so old it is impossible to read if they are the correct ones, but i guess they were never changed, same as in the circuit.

    June 24, 2016 at 7:42 pm in reply to: Vintage Zipper Envelope Filter #121657
    Camarada78
    Participant

    IC 1 (14 pins)

    1 = 7.05 8 = nothing
    2 = 6.95 9 = nothing
    3 = nothing 10 = 3.61
    4 = 8.29 11 = 0.71
    5 = 0.07 12 = nothing
    6 = 7.01 13 = 6.53
    7 = 7.01 14 = 7.03

    IC 2 (8 pins)

    1 = 2.45 5 = nothing
    2 = 2.55 6 = starts and 2.20 and drops to 1.39 and stabilize
    3 = 1.33 7 = 7.52
    4 = 0.71 8 = 8.29

    IC 3 (8 pins)

    1 = 2.57 5 = nothing
    2 = 2.59 6 = starts and 2.31 and drops to 1.40 and stabilize
    3 = nothing 7 = 6.52
    4 = 0.71 8 = 8.29

    FETs

    T1 = 6.95
    T2 = 0.15
    T3 = 0.11

    those were the readings. triple checked.

    Thanks for your help!

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Viewing 9 posts - 1 through 9 (of 9 total)