Problems with SWR SM-400-S

Discussion in 'Amps and Cabs [BG]' started by Cantstandsya, Aug 19, 2001.

  1. Cantstandsya


    Jul 27, 2001
    Fontana, CA
    My SM-400S shutdown on me the other night after about an hour of playing. When I turned it back on the next day it was fine for about five minutes then completely shutdown again. It wont turn back on now at all. Anyone experience similar problems?
  2. tcbglitch

    tcbglitch Guest

    May 26, 2001
    I have a used one and a week ago at practice it just shut off. Now it won't even turn on anyone more. Haven't taken it to the shop to get it looked at yet. Once I get it fixed, I'm selling it. I need some new gear that has a warranty.
  3. LowfreqB


    Nov 10, 2000
    United States
    Here’s what to do. Call SWR in Sunland CA. Tell them about it, then arrange for a walk in appointment. I see by your profile that you live in the neighborhood of 30-45 minutes from SWR. Take the 210 freeway west, exit La Tuna Canyon and turn left. Follow that road till you hit glenoaks blvd. turn right, and it should be on the right hand side of the street.

    On most occasions they might tell you to take your amp to the "amp doctor" in Hollywood. That works great if you don’t mind waiting for 6-8 weeks. Your problem sounds like something they should take a look at.

    Wait I just thought of this, you might have blown a power fuse. SWR amps are hybrid and the power section still uses fuses. Look into that.

    9130 Glenoaks Blvd.
    Sun Valley, CA 91352
    Phone: (818) 253-4797
    Fax: (818) 253-4799

    They helped me out when my BASS 350 went sick.
  4. Cantstandsya


    Jul 27, 2001
    Fontana, CA
    Actually I live about an hour and a half drive(That's with no traffic)from SWR. Unfortunately, I was just there last Tuesday to get some speakers reconed. Very cool guys but I am not looking forward to driving there again.I think you may be right about the power fuse. I looked inside and there is a fuse near the power transformer that looks blown. It has some kind of plastic or something around it though and I don't want to mess with it. Fortunately I have a good friend who is an electronics guy at Alesis. He fixed my Ampeg B2R when it when out and only charged me thirty bucks.
  5. There's an 8 amp fuse inside the box.
    It is soldiered in place and needs to be unsoldiered and re-soldiered by in place. When mine blew and I replaced it myself, but you should how to use an iron. Works fine now.

    The first power fuse excessable from the rear, a 7 amp slo-blo, the inner fuse is a 8 amp fast blo.
  6. LowfreqB


    Nov 10, 2000
    United States
    For some reason I was thinking Glendora, which is off the 210 instead of Rancho which is further east. Yeah your right that is a drive. Its just cheaper then putting your amp in the mail. Head out to the beach that day, that could make it worth it.:cool:
  7. Cantstandsya


    Jul 27, 2001
    Fontana, CA
    Thanks for the info man. I'll definitely make a day of it next time i drive out there.
  8. Rock City

    Rock City

    Apr 8, 2001
    I don't think you blew a fuse! If you did it wouldn't have come back on the following day!!!!!!!! I had an SM-400s(HATED that amp!) and mine was shutting down when driven hard for 10-15 min. It turns out that SWR had FORGOTTEN to plug the fan into the circuit board!! You might want to take a look inside and see if this is the case.
    BE VERY CAREFUL!!!!!!!
  9. BWB

    BWB Supporting Member

    Aug 30, 2000
    Knoxville TN
    Note about servicing amplifiers (or anything else

    A blown fuse is an INDICATOR of a problem - not a
    problem itself. Don't continue to replace fuses
    (or worse) defeat the fuse circuitry by shorting it out. Have the amp looked at before the damage goes from bad to worse. Fuses are there to protect your equipment from further damage should a fault in the system arise.

  10. LowfreqB


    Nov 10, 2000
    United States
    Scott, as in Scott Rabe?
  11. I have two and they have been reliable since new. That's ten years I'd say. I have them each in a calzone rack case and one fell out of the back of a parked SUV onto the corner of the case onto cobble stone streets that are about two hundred years old. It worked fine but a few months later it wouldn't turn on. $50 later it was fixed and it was just something little, a pwr supply connection. Things happen and I can say all my SWR gear is reliable and sounds good and predictable every where.
  12. Had a weird almost blown speaker distortion on low notes in one of my sm-400s and a weird phasey sound from my baby blue II during a recording session. Guess what? New preamp tubes and they are sweet clear and full! If you buy a used one consider this.
  13. tcbglitch

    tcbglitch Guest

    May 26, 2001
    I had the same problem, as I stated earlier in the thread. My SM-400S wouldn't turn on at all. I went to radioshack and replaced a slow blow fuse in it and now if works fine. Only cost $2 to fix. How about that!? Didn't have to take it across town and pay $50 to have someone look at it. Not bad. Check your fuses, if one may be blown, go ahead and replace it. A quick and cheap fix. :cool:
  14. pkr2

    pkr2 Guest

    Apr 28, 2000
    coastal N.C.
    A good tip to keep in mind when replacing a blown fuse:

    Look at the glass part of the fuse before replacing it. If the glass is not blackened it's probably safe to replace it. If the glass is covered with black on the inside it usually indicates a dead short and replacing and consequently blowing the new fuse can wipe out parts that may have survived the original blow.

    If the blown fuse has clean glass, chances are good that a thermal failure is the prob and a simple replacement will get you up and running. In that case check the EQ settings for clipping.

    NEVER replace a fuse the second time it blows without finding the source of the problem.

    For the techy guys: after replacing a blown fuse, put a regular 40 watt lightbulb in series with the power cord. Turn the amp on and if the bulb glows at normal brightness, STOP. Carry the amp to a tech or dig deeper for the problem.

    If the bulb glows at about half brightness or less everything is probably normal.

    The bulb will limit the current to a safe level rather than eating more parts up.

    BE CAREFUL, there are voltages in that sucker that can easily be lethal.

    A good idea is to only work with one hand. If you get a shock, the voltage doesn't pass from one hand, through the chest and out the other hand.

    DavesnothereCA likes this.