Help I think my Plexi died!

banditguitarist1

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so today I had my plexi on with my THD Hot plate same Ohm value as the amp and I had it on standby just warming up for awhile. Well I had to go out so I shut it off and while getting ready I noticed a strange burning smell which was coming from the amp when I tried to turn i tback on nothing no sound no light.

I took out the fuse and found it blow and now the amp is not turning on at all, no light, no sound no nothing please help me out what could it be? Just the fuse or did I lose the whole 9.
 

analogsystem

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with no fuse it won't even power up.

Replace the fuse and turn the amp on with the volume turned way down. If you are lucky the fuse blew in time to save the amp. I don't know much about those THD hotplates but I remember hearing lots of storries about people frying their amps with the old Marshall Powerbrakes. I stay away from attenuators and just play loud.
 

axepilot

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Just how do you set a THD Hot Plate to a "ohm setting"? They are set to a specific impedance from the factory.

A burning smell is not good..................tech time.
 

Paragon

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Yeah.. if there was that usual electrical burning smell, then sounds like something fried inside taking the fuse out. You can always take a look and see if there is anything burned on the board inside... or take it to a tech.
 

axepilot

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Fuse blowing due to transients - replace the fuse and check from there.

Fuse blowing with the fried electronics smell - tech time.
 

banditguitarist1

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Thanks guys, I am probably going to take it to 30th Street Vintage guitars. When I say same ohm setting i mean the same impedance 8ohms. The fuse did blow, where can I get a replacement fuse? Right now the amp does not turn on at all. Hopefully this isn't the 2nd time I've blown up my plexi...
 

Paragon

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Without a new fuse, no power is getting to the amp. You need to get the same fuse as specified for the amp (Amp rating and blow speed). If you smelled something like that electronics burned smell, then you should have it checked out since you are probably going to just blow any fuse you put in there.
 

Blind Lemon

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The fuse blew because the amp circuitry was pulling more amperage than it was designed to handle... ie: something shorted out inside, that smell means something, it got too hot. Don't waste your money on fuses until you find out what burnt up.:shock:

BL
 

SiriusAbbott

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The fuse blew because the amp circuitry was pulling more amperage than it was designed to handle... ie: something shorted out inside, that smell means something, it got too hot. Don't waste your money on fuses until you find out what burnt up.:shock:

BL
And you can take Blind Lemons advice to the bank,the man built the best sounding amp I have ever played through....so I bought it :thumb:
 

Blind Lemon

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SA whats happen'. Aint heard from you in a while. Take a look a this one............:thumb:

Still have it at the house if you want to plug in..............
 

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SiriusAbbott

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SA whats happen'. Aint heard from you in a while. Take a look a this one............:thumb:

Still have it at the house if you want to plug in..............

BL....what in the hell is up with all those extra knobs on that rocket? :shock:
oh crap,now I am gonna have to buy another one :naughty: :)



sorry I havent been in touch lately,been busy with county problems(sewer/drain issues) and trying to stay alive in a very very sluggish economy :rolleyes: also moved youngest daughter back in with me so she can have her baby in a calmer environment......imagine that,a rock and roll guitarists house a "calmer environment" :laugh2:
 

banditguitarist1

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Thank you for the advice Blind Lemon, I'm going to take it to 30th Street Vintage Guitars sometime soon and have them sort it out. I fear I might sell this after this repair because this is the 2nd time it has blown up on me...I am really attached to that amp since it was my dream amp for so long (come on who doesnt look at Page and Hendrix and Clapton with there plexi's and long for one) but its been a nonstop trainwreck and not in a good way.

IF and thats a big IF, sell it what do you think is a good more solid replacement that still has that plexi tone? I've always lusted after a bluesbreaker or a JTM45 something with that same old school "Brown Sound". Thanks again for all your help guys when it happened today I was so heartbroken and couldn't figure out what happened I switched it from standby to off and that was it!

Now I guess its time for the techs to handle her, and thank god I got my Rockerverb:dude:
 

SiriusAbbott

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Thank you for the advice Blind Lemon, I'm going to take it to 30th Street Vintage Guitars sometime soon and have them sort it out. I fear I might sell this after this repair because this is the 2nd time it has blown up on me...I am really attached to that amp since it was my dream amp for so long (come on who doesnt look at Page and Hendrix and Clapton with there plexi's and long for one) but its been a nonstop trainwreck and not in a good way.

IF and thats a big IF, sell it what do you think is a good more solid replacement that still has that plexi tone? I've always lusted after a bluesbreaker or a JTM45 something with that same old school "Brown Sound". Thanks again for all your help guys when it happened today I was so heartbroken and couldn't figure out what happened I switched it from standby to off and that was it!

Now I guess its time for the techs to handle her, and thank god I got my Rockerverb:dude:

dude,take it from a diehard Marshall fanatic....one word......."boutique" :dude:
Take BL for example,I called my old amp guy and asked him about a custom build,turns out he was winding his business down due to health issues,but he knew a guy,and would call me back.
He calls me a day or two later and says drop by the shop,his associate has an amp that I should test drive.
I arrive at the appointed time,walked in and met BL,and was promptly introduced to the Peckerhead Rockit 30 :wow:
I literally hit a few chords,had a personal "holy shit" moment.....and said...."how much?"
My live rig is a tri-amp set-up,a heavily modified Marshall JCM900 combo running a Marshall 4X12,an Ampeg VL-1003 running 2 Marshall 4X12s and my Peckerhead Rockit 30 running a Zinky 2X12...my Peckerhead Rockit 30 is mainly my solo amp :dude:

in my 33 years of playing its as close as I have come to the ultimate tone.
 

Blind Lemon

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What happened to it last time and which model is it? If you love it don't be so fast to get rid of it.

BL
 

Liam

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Thank you for the advice Blind Lemon, I'm going to take it to 30th Street Vintage Guitars sometime soon and have them sort it out. I fear I might sell this after this repair because this is the 2nd time it has blown up on me...I am really attached to that amp since it was my dream amp for so long (come on who doesnt look at Page and Hendrix and Clapton with there plexi's and long for one) but its been a nonstop trainwreck and not in a good way.

Something weird with this. Plexi's are bomb proof, they just don't go wrong. Quite how one can blow up while on standby I'm still trying to figure out. Who normally services it for you? Who did the work on it last time it blew up? They might have screwed up in some way.

You need to get it to someone that knows what they are doing with Marshalls and get it fully serviced and checked over. If it's done properly you will have no further trouble with it.

Liam
 

banditguitarist1

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Something weird with this. Plexi's are bomb proof, they just don't go wrong. Quite how one can blow up while on standby I'm still trying to figure out. Who normally services it for you? Who did the work on it last time it blew up? They might have screwed up in some way.

You need to get it to someone that knows what they are doing with Marshalls and get it fully serviced and checked over. If it's done properly you will have no further trouble with it.

Liam

Its normally serviced by 30th Street Vintage Guitars in Manhatten, they also did the previous repairs however that was a good three years ago and it hasn't really had any major work done since then. It runs full out anytime I use it and I limit the volume with a hot plate.

The last time it blew up was due to a power surge that occurred at a friends house that blew the fuse which then caused the cheap chinese tubes that the previous owner installed to blow and basically the whole thing fried.
 

Liam

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Maybe you misunderstood what they told you last time. If the fuse blows, then the amp can't "fry". Once the fuse has blown the amp is effectively switched off.

I've worked on amps where cheap tubes have "run away" with themselves before, but that normally just takes out the HT fuse, sometimes the screen grid resistors. Occasionally if you're really unlucky the output transformer, but never the entire amplifier. I'm quite surprised you had such a catastrophic failure last time.

If the amp had done what you said in anything other than standby mode, I would have said it was a power tube failure. But as it has done it in standby, I can't see what it can be other than the mains transformer.

Let them know you're running it flat out all the time when you get them to look at it. They might want to bias it a little cooler. If you're driving it really hard for more than about 10 hours a week you probably need to change output tubes every year. Sounds like you've been very unlucky with this amp, they are normally reliable.

Liam
 

banditguitarist1

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Maybe you misunderstood what they told you last time. If the fuse blows, then the amp can't "fry". Once the fuse has blown the amp is effectively switched off.

I've worked on amps where cheap tubes have "run away" with themselves before, but that normally just takes out the HT fuse, sometimes the screen grid resistors. Occasionally if you're really unlucky the output transformer, but never the entire amplifier. I'm quite surprised you had such a catastrophic failure last time.

If the amp had done what you said in anything other than standby mode, I would have said it was a power tube failure. But as it has done it in standby, I can't see what it can be other than the mains transformer.

Let them know you're running it flat out all the time when you get them to look at it. They might want to bias it a little cooler. If you're driving it really hard for more than about 10 hours a week you probably need to change output tubes every year. Sounds like you've been very unlucky with this amp, they are normally reliable.

Liam

Thanks for the help Liam, I'm really interested to hear what actually went wrong when I take it down there. However I need to get paid first:laugh2: and then Im bring my 67 Mustang and the plexi in for some work.

Hopefully its not a horrible problem, I don't really use the plexi alot either which is the weird part I usually run my orange and when I'm playing something classic like Zeppelin or Free I use my plexi so its weird as it gets light use. Hopefully it will get repaired and be alright if its still got issues then I guess I'm going to have to move on even though I'd rather not.
 

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