Search results

  1. fer1991

    Sc20h treble resistor

    Thanks for the explanation, it was the R103 the one that was changed in my amp many times, so now I can trust the value, thanks!
  2. fer1991

    Sc20h treble resistor

    Hello everyone! I’m on vacation and thought about spending some time with my amp. I’m not good at reading schematics, but as far as I can understand there’s a resistor and a capacitor attached to the treble pot in the 2203 schematics, a 33k resistor and a 470p capacitor. Since my sc20h has been...
    • fer1991
    • Thread
    • 2203 800 jcm jcm800 sc20h studio treble
    • Replies: 2
    • Forum: The Workbench
  3. fer1991

    sc20h STBY switch

    Hello everyone! I hope everyone it's fine. Last weekend I disassembled my sc20h for several reasons but the thing is, I don't know how to properly rewire the standby switch. As you can see, I'm not clever enough to look for pictures since I've got three black wires going to the switch. The...
  4. fer1991

    sc20h power

    Thanks again! I got intrigued by the resistor changed in the eq section. I also think that the volume drop isn't an issue, but if the R103 changes the eq shape that would intrigue me again.
  5. fer1991

    sc20h power

    @PelliX Sorry for the delay, I have some personal things going on and I didn't have the time to do the test. I went looking for the multimeter's cables and they didn't have them in stock, so I guess I'm leaving it as things came from the factory, since now I feel everything should be correct...
  6. fer1991

    sc20h power

    That's exactly right, doctors make the worst patients! We do have forums nowadays, but the more connected we are, the more "figure that out for yourself " we end up finding sometimes, so, you've made some guy happy on the other side of the globe, I can now play just knowing that everything it's...
  7. fer1991

    sc20h power

    Sir, you have been patient and teachfull to me, really, thank you very much. I hope they were a couple of beers, you truly deserve them. Around the week I'll seek for better clipping or alligator cables to take the measurements. If I understood well I think it should be taken with the positive...
  8. fer1991

    sc20h power

    I didin't get it, how should I set the multimeter and exactly where should I put the positive's and negative's tips/wires to measure??
  9. fer1991

    sc20h power

    So, we've got the polarity corrected at our cables, the female does have the lead in the right side. So, polarity has never been an issue?
  10. fer1991

    sc20h power

    I feel comfortable doing this kind of tests and I have a multimeter, but I'm not certain about how it should be done. I don't know exactly where I have to take the measures and what should they read
  11. fer1991

    sc20h power

    Looking again at your photo and my videos, Marshall uses blue and brown for Live and Neutral, that's how they reach the fuses. Wouldn't a polarity change be swapping only the white/blue - red/brown above/below order? - white/fuse/blue - red/fuse/brown What I mean is don't know why he swapped...
  12. fer1991

    sc20h power

    Well.. I checked at home, and we use the Live wire at the left side of the female plug. I even detected one extension cable that was wired opossited (as Australia does), and that's way I always had some ground noise when using the guitar and using the phone while connected to the wall in that...
  13. fer1991

    sc20h power

    Yes, you're right, on top of all of that, I live in Argentina where we had type C connectors, and now type I. So every socket is wired differently. Yes.. every socket should be installed by a professional.. but that's not reality. So you are right, I just can not know witch's live and witch's...
  14. fer1991

    sc20h power

    Thanks for the photo, that's the way I put the wires. Since brown and red are a pair, and so white and blue, wouldn't it make more sense to put the leads in front of the fuses?? So I guess he took the red as a lead cable instead of the brown?? (Hi and Low works fine, and it worked with the...
  15. fer1991

    sc20h power

    To be honest, I really don't know how transformers work and I don't know what every cable it's supposed to do, so I'm gonna leave it as it came from the factory. The only things I could try to guess with this is that the blue and brown cables look like they were positive and negative, they leave...
  16. fer1991

    sc20h power

    Since I'm no expert in schematics or Photoshop, I'll try this way. They changed the order from the 4 wires coming from the power supply, this way. (I wrote the original wire on the sides)
  17. fer1991

    sc20h power

    When I read somewhere about a "fix" or "upgrade" I wrote Marshall uk and got answered by the official service in my country. They were far away from where I live but took the amplifier to them. When I got it back, I saw the poorly work done, and since I could do a better job I put everything as...
  18. fer1991

    sc20h power

    Hi everyone, I've got an oldy thing to discuss today. In the past I've taken my sc20h to the service to fix the fx loop (I'm leaving here a post where I talk about it) with very very bad experience with the service. the link...
  19. fer1991

    Anyone get the SC20 loop fix implemented?

    @Kutt Hey Kutt, thanks for this images, because I thought that at first. I inmediately blamed the quality job, and since they wouldn't show me that information (they shared the values but I just had to trust them) I had my doubts about tryin it again. But, not for me yet. These amps here are...
  20. fer1991

    Anyone get the SC20 loop fix implemented?

    Hi, sorry for the delay, I did indeed took the amplifier to the service. Things went south when the service was just horribly. Really poorly job done when they changed three resistors for these values: R36 220k, R38 27k, R103 470k. The job was so poorly done that I just researched for the...

Latest posts



Top