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Thread: Deluxe Reverb RI suddenly blowing fuses, ideas?

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    Forum Member 1Duffy1's Avatar
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    Deluxe Reverb RI suddenly blowing fuses, ideas?

    My Fender DRRI, about six months old, bought new, suddenly started blowing fuses yesterday. It blew three fuses.
    We had a heavy electrical storm that knocked out the power two days ago. It could have blown the fuse then but I noticed it yesterday. The power outage did not blow any fuses in the house or damage any other equipment.
    I have been leaving the DRRI "on" in my studio a lot, for extended hours without switching to standby.
    Could this indicate that the "rectifier tube" has gone bad? The rectifier keeps the current at a regulated, constant level doesn't it? This is the only idea I have.
    Does anyone know which tube is the rectifier tube. There are three tubes at the very right of the cabinet looking at it from the back. Is sit the farthest to the side? Directly next to the side of the cabinet?
    Would a visual check of the rectifier tube show any signs of it being bad?
    When I put a new fuse in the amp the amp works fine and I can play for about four or five minutes before it blows.
    Any ideas?
    Yes it is still under warranty and will go in for repair if I can't locate a simple problem.
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    Forum Member Kap'n's Avatar
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    Re: Deluxe Reverb RI suddenly blowing fuses, ideas?

    If an amp blows a single fuse, it doesn't necessarily mean anything. The little wire inside can get fatigued from vibration.

    If it blows a second one in rapid succession, there is a short circuit in the amp. That's what the fuse is there for, to prevent consequential damage from the primary point of failure.

    Bring it to a tech.
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    Forum Member cdw2000's Avatar
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    Re: Deluxe Reverb RI suddenly blowing fuses, ideas?

    I don't have a DRRI to look at but the product manual says there is a tube layout chart stuck to the inside of the cabinet. The tube labeled "5AR4" is the rectifier tube.

    The rectifier does not regulate the current, it converts the AC to DC (along with the filter capacitors). A fuse blowing is not necessarily an indication that the rectifier tube is bad.

    But first things first, I am assuming the replacement fuses you are using have the same current and voltage rating as the original fuse, correct?

    Given that, here is the trubleshooting tree I would use, assuming you do not have the technical skills to go inside the box (lethal voltages in there):

    Step 1. Are the heaters working in all the tubes? (Turn the amp on and after about 30 secs you should see an orange glow eminating from the interior of each tube). Replace any tube that does not have a working heater.

    Step 2. Check to see if the fuse blows after a time while the amp is in standby. The standby switch is after the rectifier tube, so if it is a bad rectifier tube it could still blow the fuse when the amp is in standby.

    >> If the fuse does blow, go to Step 3.

    >> If the fuse doesn't blow, it is something down-circuit of the standby switch. Go to step 4.

    Step 3. Turn off the amp, replace the fuse, remove the rectifier tube, and turn the amp back on (can leave in standby). Check to see if the fuse still blows.

    >> If the fuse does blow, the culprit could be the power transformer, time to take it in for an authorized repair. <Done>

    >> If the fuse doesn't blow, it is most likely the rectifier. Go ahead and replace it. <Done>

    Step 4. Remove all the tubes, taking careful note of which tube came out of which socket. Turn on the amp and check to see if the fuse blows.

    >> If the fuse does blow, the problem is probably in the internal circuitry. Take it in for an authorized repair. <Done>

    >> If the fuse does not blow, it could be one of the other tubes. Go to Step 5.

    Step 5. With the amp off, re-insert the rectifier tube. Test each tube one at a time (do the 6V6 power tubes together) by inserting it, powering up the amp, taking it out of standby and seeing if the fuse blows.

    >> If the fuse blows, replace the culprit tube (or both power tubes if they are the culprit. <Done>

    >> If the fuse never blows in this step, it could be a borderline over-current issue that will require some more in-depth troubleshooting. Time to take it in for service.


    Hope this helps.
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    Forum Member 1Duffy1's Avatar
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    Re: Deluxe Reverb RI suddenly blowing fuses, ideas?

    Quote Originally Posted by cdw2000 View Post
    I don't have a DRRI to look at but the product manual says there is a tube layout chart stuck to the inside of the cabinet. The tube labeled "5AR4" is the rectifier tube.

    The rectifier does not regulate the current, it converts the AC to DC (along with the filter capacitors). A fuse blowing is not necessarily an indication that the rectifier tube is bad.

    But first things first, I am assuming the replacement fuses you are using have the same current and voltage rating as the original fuse, correct?

    Given that, here is the trubleshooting tree I would use, assuming you do not have the technical skills to go inside the box (lethal voltages in there):

    Step 1. Are the heaters working in all the tubes? (Turn the amp on and after about 30 secs you should see an orange glow eminating from the interior of each tube). Replace any tube that does not have a working heater.

    Step 2. Check to see if the fuse blows after a time while the amp is in standby. The standby switch is after the rectifier tube, so if it is a bad rectifier tube it could still blow the fuse when the amp is in standby.

    >> If the fuse does blow, go to Step 3.

    >> If the fuse doesn't blow, it is something down-circuit of the standby switch. Go to step 4.

    Step 3. Turn off the amp, replace the fuse, remove the rectifier tube, and turn the amp back on (can leave in standby). Check to see if the fuse still blows.

    >> If the fuse does blow, the culprit could be the power transformer, time to take it in for an authorized repair. <Done>

    >> If the fuse doesn't blow, it is most likely the rectifier. Go ahead and replace it. <Done>

    Step 4. Remove all the tubes, taking careful note of which tube came out of which socket. Turn on the amp and check to see if the fuse blows.

    >> If the fuse does blow, the problem is probably in the internal circuitry. Take it in for an authorized repair. <Done>

    >> If the fuse does not blow, it could be one of the other tubes. Go to Step 5.

    Step 5. With the amp off, re-insert the rectifier tube. Test each tube one at a time (do the 6V6 power tubes together) by inserting it, powering up the amp, taking it out of standby and seeing if the fuse blows.

    >> If the fuse blows, replace the culprit tube (or both power tubes if they are the culprit. <Done>

    >> If the fuse never blows in this step, it could be a borderline over-current issue that will require some more in-depth troubleshooting. Time to take it in for service.


    Hope this helps.
    I am going to try this. I need to get some 2A 250 volt BUS fuses. Any idea who would carry them - auto parts, electrical supply house?
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    Forum Member Kap'n's Avatar
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    Re: Deluxe Reverb RI suddenly blowing fuses, ideas?

    Radio Shark might still carry them.

    Auto fuses are typically a much, much higher current rating, and would be potentially dangerous to use in an amp as they wouldn't blow unless you were undergoing total meltdown..
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    Forum Member Wilko's Avatar
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    Re: Deluxe Reverb RI suddenly blowing fuses, ideas?

    Quote Originally Posted by 1Duffy1 View Post
    I am going to try this. I need to get some 2A 250 volt BUS fuses. Any idea who would carry them - auto parts, electrical supply house?
    Why do you want "2A 250 volt BUS" fuses?

    From the manual:

    FUSE TYPE: 2A, 125V (100-120V versions)
    F1A, 250V (230-240V versions)

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    Forum Member cdw2000's Avatar
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    Re: Deluxe Reverb RI suddenly blowing fuses, ideas?

    I took a look and did not find an appropriate fuse on Radio Shack's website. You could try a good hardware store. They may have them, though they may be pricey.

    On the fuse, current rating is most important. A 2A 250V fuse would be OK to use if you can't find one rated at 125V.
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    Forum Member Don's Avatar
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    Re: Deluxe Reverb RI suddenly blowing fuses, ideas?

    A 250v fuse is fine. Just don't go under the voltage rating and always use the same amperage rating and type. Radio Shack has them listed on their site.

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    Forum Member 1Duffy1's Avatar
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    Re: Deluxe Reverb RI suddenly blowing fuses, ideas?

    I got some fuses as backups. Those 250 volt ones were the same rating as the one in the stock amp from the factory.

    I dropped the amp off yesterday and it is on its way to the authorized Fender amp repair man, who is, incidentally, a professor/technical instructor at Penn State in State College.

    It should be done in around two weeks.

    Also, on another note, I bought a set of the new "Cobalt" strings and put them on my new Fender '72 Telecaster Custom, and they really sound nice in my opinion. Maybe the stock strings were old or just not very good strings, but this guitar really sounds great now - a noticeable difference: more powerful sounding and a great full sound. They are definitely worth checking out. I'll be buying more.

    Thanks for the info on the amp problem and the fuses.

    That DRRI is an awesome amp. I'm using my tweed special edition Hot Rod Deluxe while it is away and it is a great amp too. I'm going to keep it set up.
    "Walk along the river, sweet lulla by, it just keeps on flowing,
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    Forum Member cdw2000's Avatar
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    Re: Deluxe Reverb RI suddenly blowing fuses, ideas?

    Probably for the best. There are limited things that can be done to troubleshoot without opening it up.

    Best to get it fixed under warranty.
    "Time is an illusion, lunchtime doubly so" -- Douglas Adams
    "If something has a 1 in a million chance of occurring, 9 times out of 10 it will happen" -- Terry Pratchett

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    Forum Member Wilko's Avatar
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    Re: Deluxe Reverb RI suddenly blowing fuses, ideas?

    I'd get it fixed.

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    Forum Member 1Duffy1's Avatar
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    Re: Deluxe Reverb RI suddenly blowing fuses, ideas?

    The amp came new from Fender with the 2 amp 250 volt fuse.

    I'll see what the authorized repair guy puts back in.
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    Forum Member Don's Avatar
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    Re: Deluxe Reverb RI suddenly blowing fuses, ideas?

    There's nothing wrong with that amp using a 250 volt fuse. It just has to be at least 125 volts.

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    Forum Member Wilko's Avatar
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    Re: Deluxe Reverb RI suddenly blowing fuses, ideas?


  15. #15
    Forum Member Don's Avatar
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    Re: Deluxe Reverb RI suddenly blowing fuses, ideas?

    125v is the minimum required voltage rating for the fuse. You can use 250v with no problems. Either is the "correct" fuse.

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    Forum Member Cygnus X1's Avatar
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    Re: Deluxe Reverb RI suddenly blowing fuses, ideas?

    It is the current rating that counts, not just the voltage rating.
    125 is a minimum.
    250 will serve the same purpose.
    Observe the "A" rating, and whether it a slo-blo or not.

    As Don noted.

    I use 250V slo-blo fuses exclusively to minimize nuisance triggers.

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