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My amp's power cable was tripped on...
Old 5 days ago
  #1
Gear Head
 

My amp's power cable was tripped on...

My amp's power cable was tripped on way back when and out of panic I rushed to plug it back in while everything was still on. I heard what sound like surge of electricity and the amp powered down shortly after. It has never turned on since. It's not a particularly expensive amp and has little priority to me as of right now, but out of curiosity to maybe one day find a fix, what could have possibly happened to it based off of my description? Not sure if its like a transformer blew or something. IIRC, there may have been a faint burnt smell. I wasn't sure where to post this or what topic would be best suited for it, so if you have a better subforum or topic, let me know.

Thanks!
Old 5 days ago
  #2
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MarkF48's Avatar
May not help, but what is the make and model of the amp?
Old 5 days ago
  #3
Gear Head
 

Its a B-52 AT100.
Old 3 days ago
  #4
Gear Addict
 
ToddP's Avatar
 

Is the fuse ok?
Old 3 days ago
  #5
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DCtoDaylight's Avatar
 

It's possible that the tripping yanked or jerked the cord in some way that damaged its internal insulation or stressed the connection points inside the amp, such that you have a short between the two sides of the incoming AC. Checking the fuse is a good idea. If it's blown you could try replacing it; if it immediately blows again you'll have a good start on the troubleshooting process.
Old 3 days ago
  #6
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MarkF48's Avatar
Quote:
the amp powered down shortly after
To what extent did it 'power down'? Pilot lamp on front not lit, tubes not lit/glowing, and/or no sound.

Voltages in the amp could kill you if you don't know what your doing
Even with the amp unplugged, the capacitors in the amp can hold a charge for a long while and could give a shock that may not kill you, but can hurt pretty bad.


- If the pilot lamp is not lit and there is no sound, check fuse F1 in the diagram below (highlighted in red).
- If the pilot lamp is lit and the tubes seem to being glowing (heaters/filaments), but no sound....
......a)check 'Standby' switch is not in 'Standby'
......b)check fuses F1A, F2 and F3 (highlighted in red).

There is a 'thermistor' (RT1 C60-11) located after fuse F1 in the AC supply side circuit. The thermistor limits surges into the amp. When cold the resistance is high and limits an 'inrush' of current as the amps powers up. As the thermistor heats up due to current flowing through it, its resistance goes down to allow full current to the amp. If the thermistor was still hot when the amp got repowered, it may have allowed a surge. Thermistors occasionally do fail.
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My amp's power cable was tripped on...-amp-problem.jpg  
Old 2 days ago
  #7
Gear Head
 

The amp powered down to absolutely no response. No pilot light, no tubes, no sound.
Would a fusing blowing cause an electric burn smell?
Old 2 days ago
  #8
Lives for gear
 

A burning smell means something is damaged. If you don't know your way around high-voltage gear, have a tech check it out. It could be as simple as a blown cathode resistor, which in some amps acts as a B+ backup fuse... or not. Remember, the power supply caps in tube amps can hold a big charge for a long time, and getting zapped can really hurt. That said, if you open it up, you might be able to see scorching or melted components that would provide some clues.
Old 2 days ago
  #9
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MarkF48's Avatar
Burnt smell could be a fried thermistor which took a hit. Since the pilot light and tubes aren't lighting, either or both the fuse F1 and/or thermistor are open so the AC supply isn't getting to the power transformer. The power transformer has a possibility of being toast also. Image below shows the thermistor in the green box. Try an new fuse in the holder on the back of the chassis. Be sure to use the exact replacement voltage and amps. Read what is on the old fuse.

Here's a read about a dead B52 AT100..... B-52 AT-100, won't power on... please help!
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My amp's power cable was tripped on...-at100.jpg  
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